diff --git a/.hlint.yaml b/.hlint.yaml
index bc1b09a86..96ea24647 100644
--- a/.hlint.yaml
+++ b/.hlint.yaml
@@ -48,6 +48,7 @@
 - ignore: {name: Use ., within: [Analysis.Abstract.Graph.graphingModules]}
 
 - ignore: {name: Reduce duplication, within: [Semantic.Util]}
+- ignore: {name: Use newtype instead of data, within: [Semantic.Api.V1.CodeAnalysisPB]}
 
 # Our customized warnings
 
diff --git a/proto/semantic.proto b/proto/semantic/api/v1/code_analysis.proto
similarity index 82%
rename from proto/semantic.proto
rename to proto/semantic/api/v1/code_analysis.proto
index 35954303d..f4aa85167 100644
--- a/proto/semantic.proto
+++ b/proto/semantic/api/v1/code_analysis.proto
@@ -1,13 +1,11 @@
-// This file was generated by proto-gen. Do not edit by hand.
 syntax = "proto3";
 
-package github.semantic;
+package semantic.api.v1;
 
-option java_package = "com.github.semantic.analysis";
-option go_package = "github.com/semantic/analysis/;analysis";
-
-// Semantic's CodeAnalysis service provides endpoints for parsing, analyzing, and comparing source code.
+option java_package = "com.github.semantic.api.v1";
 
+// Semantic's CodeAnalysis service provides endpoints for parsing, analyzing,
+// and comparing source code.
 service CodeAnalysis {
   // Check health & status of the service.
   rpc Ping (PingRequest) returns (PingResponse);
@@ -58,7 +56,7 @@ message TermEdge {
 }
 
 message TermVertex {
-  int64 vertexId = 1;
+  int64 vertex_id = 1;
   string term = 2;
   Span span = 3;
 }
@@ -86,7 +84,7 @@ message TOCSummaryChange {
   string category = 1;
   string term = 2;
   Span span = 3;
-  ChangeType changeType = 4;
+  ChangeType change_type = 4;
 }
 
 message TOCSummaryError {
@@ -119,16 +117,12 @@ message DiffTreeEdge {
 }
 
 message DiffTreeVertex {
-  int64 diffVertexId = 1;
-  DiffTreeTerm diffTerm = 2;
-}
-
-message DiffTreeTerm {
-  oneof sum {
-    DeletedTerm deleted = 1;
-    InsertedTerm inserted = 2;
-    ReplacedTerm replaced = 3;
-    MergedTerm merged = 4;
+  int64 diff_vertex_id = 1;
+  oneof diff_term {
+    DeletedTerm deleted = 2;
+    InsertedTerm inserted = 3;
+    ReplacedTerm replaced = 4;
+    MergedTerm merged = 5;
   }
 }
 
@@ -143,16 +137,16 @@ message InsertedTerm {
 }
 
 message ReplacedTerm {
-  string beforeTerm = 1;
-  Span beforeSpan = 2;
-  string afterTerm = 3;
-  Span afterSpan = 4;
+  string before_term = 1;
+  Span before_span = 2;
+  string after_term = 3;
+  Span after_span = 4;
 }
 
 message MergedTerm {
   string term = 1;
-  Span beforeSpan = 2;
-  Span afterSpan = 3;
+  Span before_span = 2;
+  Span after_span = 3;
 }
 
 enum Language {
diff --git a/semantic.cabal b/semantic.cabal
index a2c767071..9e794ab21 100644
--- a/semantic.cabal
+++ b/semantic.cabal
@@ -183,14 +183,14 @@ library
                      -- High-level flow & operational functionality (logging, stats, etc.)
                      , Semantic.Analysis
                      -- API
-                     , Semantic.API
-                     , Semantic.API.Diffs
-                     , Semantic.API.Helpers
-                     , Semantic.API.LegacyTypes
-                     , Semantic.API.Symbols
-                     , Semantic.API.Terms
-                     , Semantic.API.TOCSummaries
-                     , Semantic.API.Types
+                     , Semantic.Api
+                     , Semantic.Api.Diffs
+                     , Semantic.Api.Helpers
+                     , Semantic.Api.LegacyTypes
+                     , Semantic.Api.Symbols
+                     , Semantic.Api.Terms
+                     , Semantic.Api.TOCSummaries
+                     , Semantic.Api.V1.CodeAnalysisPB
                      , Semantic.AST
                      , Semantic.CLI
                      , Semantic.Config
diff --git a/src/Data/Graph.hs b/src/Data/Graph.hs
index e036a2955..52820b4ea 100644
--- a/src/Data/Graph.hs
+++ b/src/Data/Graph.hs
@@ -24,6 +24,7 @@ import           Control.Effect
 import           Control.Effect.State
 import           Data.Aeson
 import qualified Data.Set as Set
+import Semantic.Api.V1.CodeAnalysisPB
 
 -- | An algebraic graph with 'Ord', 'Semigroup', and 'Monoid' instances.
 newtype Graph vertex = Graph { unGraph :: G.Graph vertex }
@@ -100,6 +101,9 @@ instance Ord vertex => Ord (Graph vertex) where
 class VertexTag vertex where
   uniqueTag :: vertex -> Int
 
+instance VertexTag DiffTreeVertex where uniqueTag = fromIntegral . diffVertexId
+instance VertexTag TermVertex where uniqueTag = fromIntegral . vertexId
+
 instance (Ord vertex, ToJSON vertex, VertexTag vertex) => ToJSON (Graph vertex) where
   toJSON     (Graph graph) = object ["vertices" .= G.vertexList graph,   "edges" .= (Edge <$> G.edgeList graph)]
   toEncoding (Graph graph) = pairs  ("vertices" .= G.vertexList graph <> "edges" .= (Edge <$> G.edgeList graph))
diff --git a/src/Rendering/Graph.hs b/src/Rendering/Graph.hs
index 3096fd6ab..f30a72db5 100644
--- a/src/Rendering/Graph.hs
+++ b/src/Rendering/Graph.hs
@@ -18,8 +18,10 @@ import Data.Patch
 import Data.String (IsString (..))
 import Data.Term
 import Prologue
-import Semantic.API.Helpers
-import Semantic.API.Types
+import Semantic.Api.Helpers
+import Semantic.Api.V1.CodeAnalysisPB
+
+import qualified Data.Text as T
 
 -- TODO: rename as this isn't a render
 renderTreeGraph :: (Ord vertex, Recursive t, ToTreeGraph vertex (Base t)) => t -> Graph vertex
@@ -45,10 +47,10 @@ diffStyle name = (defaultStyle (fromString . show . diffVertexId))
   { graphName = fromString (quote name)
   , vertexAttributes = vertexAttributes }
   where quote a = "\"" <> a <> "\""
-        vertexAttributes (DiffTreeVertex _ (Just (Deleted  (Just DeletedTerm{..}))))  = [ "label" := fromString term,  "color" := "red" ]
-        vertexAttributes (DiffTreeVertex _ (Just (Inserted (Just InsertedTerm{..})))) = [ "label" := fromString term, "color" := "green" ]
+        vertexAttributes (DiffTreeVertex _ (Just (Deleted  (Just DeletedTerm{..}))))  = [ "label" := fromString (T.unpack term),  "color" := "red" ]
+        vertexAttributes (DiffTreeVertex _ (Just (Inserted (Just InsertedTerm{..})))) = [ "label" := fromString (T.unpack term), "color" := "green" ]
         vertexAttributes (DiffTreeVertex _ (Just (Replaced (Just ReplacedTerm{..})))) = [ "label" := "Replacement",               "color" := "orange", "style" := "dashed" ]
-        vertexAttributes (DiffTreeVertex _ (Just (Merged   (Just MergedTerm{..}))))   = [ "label" := fromString term ]
+        vertexAttributes (DiffTreeVertex _ (Just (Merged   (Just MergedTerm{..}))))   = [ "label" := fromString (T.unpack term) ]
         vertexAttributes _ = []
 
 class ToTreeGraph vertex t | t -> vertex where
@@ -70,22 +72,22 @@ instance (ConstructorName syntax, Foldable syntax) =>
     termAlgebra (In ann syntax) = do
       i <- fresh
       parent <- ask
-      let root = vertex (TermVertex i (constructorName syntax) (spanToSpan (locationSpan ann)))
+      let root = vertex (TermVertex (fromIntegral i) (T.pack (constructorName syntax)) (spanToSpan (locationSpan ann)))
       subGraph <- foldl' (\acc x -> overlay <$> acc <*> local (const root) x) (pure mempty) syntax
       pure (parent `connect` root `overlay` subGraph)
 
 instance (ConstructorName syntax, Foldable syntax) =>
   ToTreeGraph DiffTreeVertex (DiffF syntax Location Location) where
   toTreeGraph d = case d of
-    Merge t@(In (a1, a2) syntax)     -> diffAlgebra t  (Merged   (Just (MergedTerm (constructorName syntax) (ann a1) (ann a2))))
-    Patch (Delete t1@(In a1 syntax)) -> diffAlgebra t1 (Deleted  (Just (DeletedTerm (constructorName syntax) (ann a1))))
-    Patch (Insert t2@(In a2 syntax)) -> diffAlgebra t2 (Inserted (Just (InsertedTerm (constructorName syntax) (ann a2))))
+    Merge t@(In (a1, a2) syntax)     -> diffAlgebra t  (Merged   (Just (MergedTerm (T.pack (constructorName syntax)) (ann a1) (ann a2))))
+    Patch (Delete t1@(In a1 syntax)) -> diffAlgebra t1 (Deleted  (Just (DeletedTerm (T.pack (constructorName syntax)) (ann a1))))
+    Patch (Insert t2@(In a2 syntax)) -> diffAlgebra t2 (Inserted (Just (InsertedTerm (T.pack (constructorName syntax)) (ann a2))))
     Patch (Replace t1@(In a1 syntax1) t2@(In a2 syntax2)) -> do
       i <- fresh
       parent <- ask
-      let (beforeName, beforeSpan) = (constructorName syntax1, ann a1)
-      let (afterName,  afterSpan) = (constructorName syntax2, ann a2)
-      let replace = vertex (DiffTreeVertex i (Just (Replaced (Just (ReplacedTerm beforeName beforeSpan afterName afterSpan)))))
+      let (beforeName, beforeSpan) = (T.pack (constructorName syntax1), ann a1)
+      let (afterName,  afterSpan) = (T.pack (constructorName syntax2), ann a2)
+      let replace = vertex (DiffTreeVertex (fromIntegral i) (Just (Replaced (Just (ReplacedTerm beforeName beforeSpan afterName afterSpan)))))
       graph <- local (const replace) (overlay <$> diffAlgebra t1 (Deleted (Just (DeletedTerm beforeName beforeSpan))) <*> diffAlgebra t2 (Inserted (Just (InsertedTerm afterName afterSpan))))
       pure (parent `connect` replace `overlay` graph)
     where
@@ -96,10 +98,10 @@ instance (ConstructorName syntax, Foldable syntax) =>
         , Member (Reader (Graph DiffTreeVertex)) sig
         , Carrier sig m
         , Monad m
-        ) => f (m (Graph DiffTreeVertex)) -> DiffTreeTerm -> m (Graph DiffTreeVertex)
+        ) => f (m (Graph DiffTreeVertex)) -> DiffTreeVertexDiffTerm -> m (Graph DiffTreeVertex)
       diffAlgebra syntax a = do
         i <- fresh
         parent <- ask
-        let root = vertex (DiffTreeVertex i (Just a))
+        let root = vertex (DiffTreeVertex (fromIntegral i) (Just a))
         subGraph <- foldl' (\acc x -> overlay <$> acc <*> local (const root) x) (pure mempty) syntax
         pure (parent `connect` root `overlay` subGraph)
diff --git a/src/Semantic/API.hs b/src/Semantic/API.hs
deleted file mode 100644
index f2659d3db..000000000
--- a/src/Semantic/API.hs
+++ /dev/null
@@ -1,14 +0,0 @@
-module Semantic.API
-  (
-    module DiffsAPI
-  , module SymbolsAPI
-  , module TermsAPI
-  , module TOCSummariesAPI
-  , module Types
-  ) where
-
-import Semantic.API.Diffs as DiffsAPI
-import Semantic.API.Symbols as SymbolsAPI
-import Semantic.API.Terms as TermsAPI
-import Semantic.API.TOCSummaries as TOCSummariesAPI
-import Semantic.API.Types as Types
diff --git a/src/Semantic/API/Types.hs b/src/Semantic/API/Types.hs
deleted file mode 100644
index 06b72e2bd..000000000
--- a/src/Semantic/API/Types.hs
+++ /dev/null
@@ -1,343 +0,0 @@
-{-# LANGUAGE DerivingVia, DeriveAnyClass, DuplicateRecordFields, LambdaCase #-}
-module Semantic.API.Types
-  (
-  -- Parse APIs
-    ParseTreeRequest(..)
-  , Blob(..)
-  , BlobPair(..)
-
-  -- Symbols for jump-to-definition
-  , ParseTreeSymbolResponse(..)
-  , File(..)
-  , Symbol(..)
-
-  -- Diff APIs
-  , DiffTreeRequest(..)
-
-  -- TOC Summaries
-  , DiffTreeTOCResponse(..)
-  , TOCSummaryFile(..)
-  , TOCSummaryChange(..)
-  , TOCSummaryError(..)
-  , ChangeType(..)
-
-  -- Diff tree graphs
-  , DiffTreeGraphResponse(..)
-  , DiffTreeFileGraph(..)
-  , DiffTreeEdge(..)
-  , DiffTreeVertex(..)
-  , DiffTreeTerm(..)
-  , DeletedTerm(..)
-  , InsertedTerm(..)
-  , ReplacedTerm(..)
-  , MergedTerm(..)
-
-  -- Parse tree graphs
-  , ParseTreeGraphResponse(..)
-  , ParseTreeFileGraph(..)
-  , TermVertex(..)
-  , TermEdge(..)
-  , ParseError(..)
-
-  -- Health Check
-  , PingRequest(..)
-  , PingResponse(..)
-
-  -- Common Types
-  , Span(..)
-  , Position(..)
-
-  -- Mime Types
-  , Protobuf
-  ) where
-
-import           Data.Aeson
-import           Data.Bifunctor (first)
-import           Data.ByteString.Lazy.Char8 as BC
-import           Data.Char (toUpper)
-import           Data.Graph (VertexTag (..))
-import           Data.Language
-import           Data.String
-import qualified Data.Text as T
-import           GHC.Generics
-import           Network.HTTP.Media ((//))
-import           Prologue
-import           Proto3.Suite as Proto3
-import           Servant.API
-
--- These types represent the public API of semantic and are used to generate
--- `proto/semantic.proto`.
---
--- Some guidelines:
---
---   * Don't write Message, Named, ToJSON, or FromJSON instances by hand, derive
---     them.
---
---   * For non-primitive types, you'll always want to use Maybe as protobuf
---     fields are always optional.
---
---   * It's usually best to map internal types to these API types so that the
---     API contract can be changed intentionally. This also makes it so that core
---     functionality doesn't have to deal with all the Maybes.
---
---   * Keep field names short and meaningful for external consumers. It's better
---     to skirt Haskell naming conventions in favor of consistency in our proto
---     files.
-
---
--- Parse/Term APIs
---
-
-newtype ParseTreeRequest = ParseTreeRequest { blobs :: [Blob] }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, FromJSON)
-
-data Blob
-  = Blob
-  { content  :: T.Text
-  , path     :: FilePath
-  , language :: Language
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, FromJSON)
-
-data BlobPair
-  = BlobPair
-  { before :: Maybe Blob
-  , after  :: Maybe Blob
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, FromJSON)
-
---
--- Symbols API
---
-newtype ParseTreeSymbolResponse = ParseTreeSymbolResponse { files :: [File] }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data File
-  = File
-  { path     :: T.Text
-  , language :: Language
-  , symbols  :: [Symbol]
-  , errors   :: [ParseError]
-  }
-  deriving stock (Generic, Eq, Show)
-  deriving anyclass (Named, Message, ToJSON)
-
-data Symbol
-  = Symbol
-  { symbol :: T.Text
-  , kind   :: T.Text
-  , line   :: T.Text
-  , span   :: Maybe Span
-  }
-  deriving stock (Generic, Eq, Show)
-  deriving anyclass (Named, Message, ToJSON)
-
---
--- Term Graph API
---
-newtype ParseTreeGraphResponse = ParseTreeGraphResponse { files :: [ParseTreeFileGraph] }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data ParseTreeFileGraph
-  = ParseTreeFileGraph
-  { path     :: T.Text
-  , language :: Language
-  , vertices :: [TermVertex]
-  , edges    :: [TermEdge]
-  , errors   :: [ParseError]
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data TermEdge = TermEdge { source :: Int, target :: Int }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data TermVertex = TermVertex { vertexId :: Int, term :: String, span :: Maybe Span }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-instance VertexTag TermVertex where uniqueTag = vertexId
-
-newtype ParseError = ParseError { error :: String }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
---
--- Diff APIs
---
-
-newtype DiffTreeRequest = DiffTreeRequest { blobs :: [BlobPair] }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, FromJSON)
-
---
--- TOC Summaries API
---
-newtype DiffTreeTOCResponse = DiffTreeTOCResponse { files :: [TOCSummaryFile] }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data TOCSummaryFile = TOCSummaryFile
-  { path :: T.Text
-  , language :: Language
-  , changes :: [TOCSummaryChange]
-  , errors  :: [TOCSummaryError]
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data TOCSummaryChange = TOCSummaryChange
-  { category :: T.Text
-  , term :: T.Text
-  , span :: Maybe Span
-  , changeType :: ChangeType
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data ChangeType
-  = None
-  | Added
-  | Removed
-  | Modified
-  deriving stock (Eq, Ord, Show, Enum, Bounded, Generic)
-  deriving anyclass (Named, MessageField, ToJSON)
-
-instance HasDefault ChangeType where def = None
-
-instance Finite ChangeType where
-  enumerate _ = fmap go [None ..] where
-    go x = (fromString (fmap toUpper (show x)), fromEnum x)
-
-instance Primitive ChangeType where
-  primType _ = primType (Proxy @(Enumerated ChangeType))
-  encodePrimitive f = encodePrimitive f . Enumerated . Right
-  decodePrimitive   = decodePrimitive >>= \case
-    (Enumerated (Right r)) -> pure r
-    other                  -> Prelude.fail ("ChangeType decodeMessageField: unexpected value" <> show other)
-
-data TOCSummaryError = TOCSummaryError
-  { error :: T.Text
-  , span  :: Maybe Span
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
---
--- Diff Tree Graph API
---
-
-newtype DiffTreeGraphResponse = DiffTreeGraphResponse { files :: [DiffTreeFileGraph] }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data DiffTreeFileGraph
-  = DiffTreeFileGraph
-  { path     :: T.Text
-  , language :: Language
-  , vertices :: [DiffTreeVertex]
-  , edges    :: [DiffTreeEdge]
-  , errors   :: [ParseError]
-  }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data DiffTreeEdge = DiffTreeEdge { source :: Int, target :: Int }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data DiffTreeVertex = DiffTreeVertex { diffVertexId :: Int, diffTerm :: Maybe DiffTreeTerm }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-instance VertexTag DiffTreeVertex where uniqueTag = diffVertexId
-
--- NB: Current proto generation only supports sum types with single named fields.
-data DiffTreeTerm
-  = Deleted  { deleted  :: Maybe DeletedTerm }
-  | Inserted { inserted :: Maybe InsertedTerm }
-  | Replaced { replaced :: Maybe ReplacedTerm }
-  | Merged   { merged   :: Maybe MergedTerm }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data DeletedTerm = DeletedTerm { term :: String, span :: Maybe Span }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data InsertedTerm = InsertedTerm { term :: String, span :: Maybe Span }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data ReplacedTerm = ReplacedTerm { beforeTerm :: String, beforeSpan :: Maybe Span, afterTerm :: String, afterSpan :: Maybe Span }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data MergedTerm = MergedTerm { term :: String, beforeSpan :: Maybe Span, afterSpan :: Maybe Span }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-
---
--- Health Check API
---
-
-newtype PingRequest = PingRequest { service :: String }
-  deriving stock (Eq, Show, Generic)
-  deriving anyclass (Message, Named, FromJSON)
-
-data PingResponse
-  = PingResponse
-  { status :: String
-  , hostname :: String
-  , timestamp :: String
-  , sha :: String
-  }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-instance MimeRender PlainText PingResponse where
-  mimeRender _ PingResponse{..} = BC.pack $
-    status <> " - " <> hostname <> " - " <> sha <> " - " <> timestamp <> "\n"
-
-
---
--- Common Types
---
-
-data Position = Position
-  { line   :: Int
-  , column :: Int
-  }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
-data Span = Span
-  { start :: Maybe Position
-  , end   :: Maybe Position
-  }
-  deriving stock (Eq, Ord, Show, Generic)
-  deriving anyclass (Message, Named, ToJSON)
-
---
--- Custom Mime Types
---
--- Servant doesn't come with protobuf support out of the box, but it's
--- very easy to add this as a valid type for decoding and encoding: all
--- you have to do is map proto3-suite's encoding and decoding functions
--- to the MimeRender/MimeUnrender typeclasses.
-
-data Protobuf
-
-instance Accept Protobuf where
-  contentType _ = "application" // "protobuf"
-
-instance Message a => MimeRender Protobuf a where
-  mimeRender _ = Proto3.toLazyByteString
-
-instance Message a => MimeUnrender Protobuf a where
-  mimeUnrender _ = first show . Proto3.fromByteString . BC.toStrict
diff --git a/src/Semantic/Api.hs b/src/Semantic/Api.hs
new file mode 100644
index 000000000..a284654af
--- /dev/null
+++ b/src/Semantic/Api.hs
@@ -0,0 +1,14 @@
+module Semantic.Api
+  (
+    module DiffsAPI
+  , module SymbolsAPI
+  , module TermsAPI
+  , module TOCSummariesAPI
+  , module Types
+  ) where
+
+import Semantic.Api.Diffs as DiffsAPI
+import Semantic.Api.Symbols as SymbolsAPI
+import Semantic.Api.Terms as TermsAPI
+import Semantic.Api.TOCSummaries as TOCSummariesAPI
+import Semantic.Api.V1.CodeAnalysisPB as Types hiding (Language(..))
diff --git a/src/Semantic/API/Diffs.hs b/src/Semantic/Api/Diffs.hs
similarity index 91%
rename from src/Semantic/API/Diffs.hs
rename to src/Semantic/Api/Diffs.hs
index f3f61c41e..4ff363278 100644
--- a/src/Semantic/API/Diffs.hs
+++ b/src/Semantic/Api/Diffs.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE GADTs, ConstraintKinds, TypeOperators, RankNTypes #-}
-module Semantic.API.Diffs
+module Semantic.Api.Diffs
   ( parseDiffBuilder
   , DiffOutputFormat(..)
   , diffGraph
@@ -26,15 +26,16 @@ import           Data.Language
 import           Data.Location
 import           Data.Term
 import qualified Data.Text as T
+import qualified Data.Vector as V
 import           Diffing.Algorithm (Diffable)
 import           Parsing.Parser
 import           Prologue
 import           Rendering.Graph
 import           Rendering.JSON hiding (JSON)
 import qualified Rendering.JSON
-import           Semantic.API.Helpers
-import           Semantic.API.Types hiding (Blob, BlobPair)
-import qualified Semantic.API.Types as API
+import           Semantic.Api.Helpers
+import           Semantic.Api.V1.CodeAnalysisPB hiding (Blob, BlobPair, Language(..))
+import qualified Semantic.Api.V1.CodeAnalysisPB as API
 import           Semantic.Task as Task
 import           Semantic.Telemetry as Stat
 import           Serializing.Format hiding (JSON)
@@ -72,21 +73,21 @@ renderJSONGraph :: (Applicative m, Functor syntax, Foldable syntax, ConstructorN
 renderJSONGraph blobPair = pure . renderJSONAdjDiff blobPair . renderTreeGraph
 
 diffGraph :: (Traversable t, DiffEffects sig m) => t API.BlobPair -> m DiffTreeGraphResponse
-diffGraph blobs = DiffTreeGraphResponse . toList <$> distributeFor (apiBlobPairToBlobPair <$> blobs) go
+diffGraph blobs = DiffTreeGraphResponse . V.fromList . toList <$> distributeFor (apiBlobPairToBlobPair <$> blobs) go
   where
     go :: (DiffEffects sig m) => BlobPair -> m DiffTreeFileGraph
     go blobPair = doDiff blobPair (const pure) render
       `catchError` \(SomeException e) ->
-        pure (DiffTreeFileGraph path lang mempty mempty [ParseError (show e)])
+        pure (DiffTreeFileGraph path lang mempty mempty (V.fromList [ParseError (T.pack (show e))]))
       where
         path = T.pack $ pathForBlobPair blobPair
-        lang = languageForBlobPair blobPair
+        lang = languageToApiLanguage $ languageForBlobPair blobPair
 
         render :: (Foldable syntax, Functor syntax, ConstructorName syntax, Applicative m) => BlobPair -> Diff syntax Location Location -> m DiffTreeFileGraph
         render _ diff =
           let graph = renderTreeGraph diff
               toEdge (Edge (a, b)) = DiffTreeEdge (diffVertexId a) (diffVertexId b)
-          in pure $ DiffTreeFileGraph path lang (vertexList graph) (fmap toEdge (edgeList graph)) mempty
+          in pure $ DiffTreeFileGraph path lang (V.fromList (vertexList graph)) (V.fromList (fmap toEdge (edgeList graph))) mempty
 
 
 sexpDiff :: (DiffEffects sig m) => BlobPair -> m Builder
diff --git a/src/Semantic/API/Helpers.hs b/src/Semantic/Api/Helpers.hs
similarity index 51%
rename from src/Semantic/API/Helpers.hs
rename to src/Semantic/Api/Helpers.hs
index a942fe365..5e86bc458 100644
--- a/src/Semantic/API/Helpers.hs
+++ b/src/Semantic/Api/Helpers.hs
@@ -1,24 +1,27 @@
 {-# LANGUAGE LambdaCase #-}
-module Semantic.API.Helpers
+module Semantic.Api.Helpers
   ( spanToSpan
   , spanToLegacySpan
   , toChangeType
   , apiBlobToBlob
   , apiBlobPairToBlobPair
+  , apiLanguageToLanguage
+  , languageToApiLanguage
   ) where
 
 import           Data.Bifunctor.Join
 import qualified Data.Blob as Data
+import qualified Data.Language as Data
 import           Data.Source (fromText)
 import qualified Data.Span as Data
 import qualified Data.Text as T
 import           Data.These
-import qualified Semantic.API.LegacyTypes as Legacy
-import qualified Semantic.API.Types as API
+import qualified Semantic.Api.LegacyTypes as Legacy
+import qualified Semantic.Api.V1.CodeAnalysisPB as API
 
 spanToSpan :: Data.Span -> Maybe API.Span
 spanToSpan Data.Span{..} = Just $ API.Span (toPos spanStart) (toPos spanEnd)
-  where toPos Data.Pos{..} = Just $ API.Position posLine posColumn
+  where toPos Data.Pos{..} = Just $ API.Position (fromIntegral posLine) (fromIntegral posColumn)
 
 spanToLegacySpan :: Data.Span -> Maybe Legacy.Span
 spanToLegacySpan Data.Span{..} = Just $ Legacy.Span (toPos spanStart) (toPos spanEnd)
@@ -32,7 +35,37 @@ toChangeType = \case
   _ -> API.None
 
 apiBlobToBlob :: API.Blob -> Data.Blob
-apiBlobToBlob API.Blob{..} = Data.Blob (fromText content) path language
+apiBlobToBlob API.Blob{..} = Data.Blob (fromText content) (T.unpack path) (apiLanguageToLanguage language)
+
+apiLanguageToLanguage :: API.Language -> Data.Language
+apiLanguageToLanguage = \case
+  API.Unknown -> Data.Unknown
+  API.Go -> Data.Go
+  API.Haskell -> Data.Haskell
+  API.Java -> Data.Java
+  API.Javascript -> Data.JavaScript
+  API.Json -> Data.JSON
+  API.Jsx -> Data.JSX
+  API.Markdown -> Data.Markdown
+  API.Python -> Data.Python
+  API.Ruby -> Data.Ruby
+  API.Typescript -> Data.TypeScript
+  API.Php -> Data.PHP
+
+languageToApiLanguage :: Data.Language -> API.Language
+languageToApiLanguage = \case
+  Data.Unknown -> API.Unknown
+  Data.Go -> API.Go
+  Data.Haskell -> API.Haskell
+  Data.Java -> API.Java
+  Data.JavaScript -> API.Javascript
+  Data.JSON -> API.Json
+  Data.JSX -> API.Jsx
+  Data.Markdown -> API.Markdown
+  Data.Python -> API.Python
+  Data.Ruby -> API.Ruby
+  Data.TypeScript -> API.Typescript
+  Data.PHP -> API.Php
 
 apiBlobPairToBlobPair :: API.BlobPair -> Data.BlobPair
 apiBlobPairToBlobPair (API.BlobPair (Just before) (Just after)) = Join (These (apiBlobToBlob before) (apiBlobToBlob after))
diff --git a/src/Semantic/API/LegacyTypes.hs b/src/Semantic/Api/LegacyTypes.hs
similarity index 98%
rename from src/Semantic/API/LegacyTypes.hs
rename to src/Semantic/Api/LegacyTypes.hs
index 2bde52f7d..5aebf7cb0 100644
--- a/src/Semantic/API/LegacyTypes.hs
+++ b/src/Semantic/Api/LegacyTypes.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE DerivingVia, DeriveAnyClass, DuplicateRecordFields #-}
-module Semantic.API.LegacyTypes
+module Semantic.Api.LegacyTypes
   ( DiffTreeRequest(..)
   , ParseTreeRequest(..)
   , ParseTreeSymbolResponse(..)
diff --git a/src/Semantic/API/Symbols.hs b/src/Semantic/Api/Symbols.hs
similarity index 79%
rename from src/Semantic/API/Symbols.hs
rename to src/Semantic/Api/Symbols.hs
index cf1fad8c8..aba033100 100644
--- a/src/Semantic/API/Symbols.hs
+++ b/src/Semantic/Api/Symbols.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE GADTs, TypeOperators, DerivingStrategies #-}
-module Semantic.API.Symbols
+module Semantic.Api.Symbols
   ( legacyParseSymbols
   , parseSymbols
   , parseSymbolsBuilder
@@ -13,14 +13,16 @@ import           Data.ByteString.Builder
 import           Data.Location
 import           Data.Maybe
 import           Data.Term
+import qualified Data.Text as T
+import qualified Data.Vector as V
 import           Data.Text (pack)
 import           Parsing.Parser
 import           Prologue
-import           Semantic.API.Helpers
-import qualified Semantic.API.LegacyTypes as Legacy
-import           Semantic.API.Terms (ParseEffects, doParse)
-import           Semantic.API.Types hiding (Blob)
-import qualified Semantic.API.Types as API
+import           Semantic.Api.Helpers
+import qualified Semantic.Api.LegacyTypes as Legacy
+import           Semantic.Api.Terms (ParseEffects, doParse)
+import           Semantic.Api.V1.CodeAnalysisPB hiding (Blob)
+import qualified Semantic.Api.V1.CodeAnalysisPB as API
 import           Semantic.Task
 import           Serializing.Format
 import           Tags.Taggable
@@ -54,18 +56,18 @@ parseSymbolsBuilder blobs
   = legacyParseSymbols blobs >>= serialize JSON
 
 parseSymbols :: (Member Distribute sig, ParseEffects sig m, Traversable t) => t API.Blob -> m ParseTreeSymbolResponse
-parseSymbols blobs = ParseTreeSymbolResponse . toList <$> distributeFor (apiBlobToBlob <$> blobs) go
+parseSymbols blobs = ParseTreeSymbolResponse . V.fromList . toList <$> distributeFor (apiBlobToBlob <$> blobs) go
   where
     go :: (Member (Error SomeException) sig, Member Task sig, Carrier sig m, Monad m) => Blob -> m File
     go blob@Blob{..} = (doParse blob >>= withSomeTerm (renderToSymbols blob)) `catchError` (\(SomeException e) -> pure $ errorFile (show e))
       where
-        errorFile e = File (pack blobPath) blobLanguage mempty [ParseError e]
+        errorFile e = File (pack blobPath) (languageToApiLanguage blobLanguage) mempty (V.fromList [ParseError (T.pack e)])
 
         renderToSymbols :: (IsTaggable f, Applicative m) => Blob -> Term f Location -> m File
         renderToSymbols blob@Blob{..} term = pure $ either (errorFile . show) (tagsToFile blob) (runTagging blob term)
 
         tagsToFile :: Blob -> [Tag] -> File
-        tagsToFile Blob{..} tags = File (pack blobPath) blobLanguage (fmap tagToSymbol tags) mempty
+        tagsToFile Blob{..} tags = File (pack blobPath) (languageToApiLanguage blobLanguage) (V.fromList (fmap tagToSymbol tags)) mempty
 
         tagToSymbol :: Tag -> Symbol
         tagToSymbol Tag{..}
diff --git a/src/Semantic/API/TOCSummaries.hs b/src/Semantic/Api/TOCSummaries.hs
similarity index 70%
rename from src/Semantic/API/TOCSummaries.hs
rename to src/Semantic/Api/TOCSummaries.hs
index 580807bfa..ff8d7c0b7 100644
--- a/src/Semantic/API/TOCSummaries.hs
+++ b/src/Semantic/Api/TOCSummaries.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE GADTs, TypeOperators, DerivingStrategies #-}
-module Semantic.API.TOCSummaries (diffSummary, legacyDiffSummary, diffSummaryBuilder) where
+module Semantic.Api.TOCSummaries (diffSummary, legacyDiffSummary, diffSummaryBuilder) where
 
 import           Analysis.TOCSummary (Declaration, declarationAlgebra)
 import           Control.Effect.Error
@@ -10,11 +10,12 @@ import           Data.Diff
 import qualified Data.Map.Monoidal as Map
 import           Data.Span (emptySpan)
 import qualified Data.Text as T
+import qualified Data.Vector as V
 import           Rendering.TOC
-import           Semantic.API.Diffs
-import           Semantic.API.Helpers
-import           Semantic.API.Types hiding (Blob, BlobPair)
-import qualified Semantic.API.Types as API
+import           Semantic.Api.Diffs
+import           Semantic.Api.Helpers
+import           Semantic.Api.V1.CodeAnalysisPB hiding (Blob, BlobPair)
+import qualified Semantic.Api.V1.CodeAnalysisPB as API
 import           Semantic.Task as Task
 import           Serializing.Format
 
@@ -37,23 +38,23 @@ legacyDiffSummary = distributeFoldMap go
     render blobPair = pure . renderToCDiff blobPair
 
 diffSummary :: (DiffEffects sig m) => [API.BlobPair] -> m DiffTreeTOCResponse
-diffSummary blobs = DiffTreeTOCResponse <$> distributeFor (apiBlobPairToBlobPair <$> blobs) go
+diffSummary blobs = DiffTreeTOCResponse . V.fromList <$> distributeFor (apiBlobPairToBlobPair <$> blobs) go
   where
     go :: (DiffEffects sig m) => BlobPair -> m TOCSummaryFile
     go blobPair = doDiff blobPair (decorate . declarationAlgebra) render
       `catchError` \(SomeException e) ->
-        pure $ TOCSummaryFile path lang mempty [TOCSummaryError (T.pack (show e)) Nothing]
+        pure $ TOCSummaryFile path lang mempty (V.fromList [TOCSummaryError (T.pack (show e)) Nothing])
       where path = T.pack $ pathKeyForBlobPair blobPair
-            lang = languageForBlobPair blobPair
+            lang = languageToApiLanguage $ languageForBlobPair blobPair
 
     render :: (Foldable syntax, Functor syntax, Applicative m) => BlobPair -> Diff syntax (Maybe Declaration) (Maybe Declaration) -> m TOCSummaryFile
     render blobPair diff = pure $ foldr go (TOCSummaryFile path lang mempty mempty) (diffTOC diff)
       where
         path = T.pack $ pathKeyForBlobPair blobPair
-        lang = languageForBlobPair blobPair
+        lang = languageToApiLanguage $ languageForBlobPair blobPair
 
         go :: TOCSummary -> TOCSummaryFile -> TOCSummaryFile
         go TOCSummary{..} TOCSummaryFile{..}
-          = TOCSummaryFile path language (TOCSummaryChange summaryCategoryName summaryTermName (spanToSpan summarySpan) (toChangeType summaryChangeType) : changes) errors
+          = TOCSummaryFile path language (V.cons (TOCSummaryChange summaryCategoryName summaryTermName (spanToSpan summarySpan) (toChangeType summaryChangeType)) changes) errors
         go ErrorSummary{..} TOCSummaryFile{..}
-          = TOCSummaryFile path language changes (TOCSummaryError errorText (spanToSpan errorSpan) : errors)
+          = TOCSummaryFile path language changes (V.cons (TOCSummaryError errorText (spanToSpan errorSpan)) errors)
diff --git a/src/Semantic/API/Terms.hs b/src/Semantic/Api/Terms.hs
similarity index 87%
rename from src/Semantic/API/Terms.hs
rename to src/Semantic/Api/Terms.hs
index f920d086a..c2d58a4ad 100644
--- a/src/Semantic/API/Terms.hs
+++ b/src/Semantic/Api/Terms.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE ConstraintKinds, GADTs, TypeOperators, DerivingStrategies #-}
-module Semantic.API.Terms
+module Semantic.Api.Terms
   (
     termGraph
   , parseTermBuilder
@@ -28,36 +28,37 @@ import           Data.JSON.Fields
 import           Data.Language
 import           Data.Location
 import           Data.Quieterm
+import           Data.Term
 import qualified Data.Text as T
+import qualified Data.Vector as V
 import           Parsing.Parser
 import           Prologue
 import           Rendering.Graph
 import           Rendering.JSON hiding (JSON)
 import qualified Rendering.JSON
-import           Semantic.API.Helpers
-import           Semantic.API.Types hiding (Blob)
-import qualified Semantic.API.Types as API
+import           Semantic.Api.Helpers
+import           Semantic.Api.V1.CodeAnalysisPB hiding (Blob, Language (..))
+import qualified Semantic.Api.V1.CodeAnalysisPB as API
 import           Semantic.Task
 import           Serializing.Format hiding (JSON)
 import qualified Serializing.Format as Format
 import           Tags.Taggable
-import Data.Term
 
 termGraph :: (Traversable t, Member Distribute sig, ParseEffects sig m) => t API.Blob -> m ParseTreeGraphResponse
-termGraph blobs = ParseTreeGraphResponse . toList <$> distributeFor (fmap apiBlobToBlob blobs) go
+termGraph blobs = ParseTreeGraphResponse . V.fromList . toList <$> distributeFor (fmap apiBlobToBlob blobs) go
   where
     go :: ParseEffects sig m => Blob -> m ParseTreeFileGraph
     go blob = (doParse blob >>= withSomeTerm (pure . render))
       `catchError` \(SomeException e) ->
-        pure (ParseTreeFileGraph path lang mempty mempty [ParseError (show e)])
+        pure (ParseTreeFileGraph path lang mempty mempty (V.fromList [ParseError (T.pack (show e))]))
       where
-        path = T.pack (blobPath blob)
-        lang = blobLanguage blob
+        path = T.pack $ blobPath blob
+        lang = languageToApiLanguage $ blobLanguage blob
 
         render :: (Foldable syntax, Functor syntax, ConstructorName syntax) => Term syntax Location -> ParseTreeFileGraph
         render t = let graph = renderTreeGraph t
                        toEdge (Edge (a, b)) = TermEdge (vertexId a) (vertexId b)
-                   in ParseTreeFileGraph path lang (vertexList graph) (fmap toEdge (edgeList graph)) mempty
+                   in ParseTreeFileGraph path lang (V.fromList (vertexList graph)) (V.fromList (fmap toEdge (edgeList graph))) mempty
 
 data TermOutputFormat
   = TermJSONTree
diff --git a/src/Semantic/Api/V1/CodeAnalysisPB.hs b/src/Semantic/Api/V1/CodeAnalysisPB.hs
new file mode 100644
index 000000000..08811a2e7
--- /dev/null
+++ b/src/Semantic/Api/V1/CodeAnalysisPB.hs
@@ -0,0 +1,548 @@
+-- Code generated by protoc-gen-haskell 0.1.0, DO NOT EDIT.
+{-# LANGUAGE DerivingVia, DeriveAnyClass, DuplicateRecordFields #-}
+{-# OPTIONS_GHC -Wno-unused-imports -Wno-missing-export-lists #-}
+module Semantic.Api.V1.CodeAnalysisPB where
+
+import Data.Aeson
+import Data.ByteString (ByteString)
+import Data.Int
+import Data.Text (Text)
+import Data.Vector (Vector)
+import Data.Word
+import GHC.Generics
+import Proto3.Suite
+import Proto3.Wire (at, oneof)
+
+data PingRequest = PingRequest
+  { service :: Text
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message PingRequest where
+  encodeMessage _ PingRequest{..} = mconcat
+    [ encodeMessageField 1 service
+    ]
+  decodeMessage _ = PingRequest
+    <$> at decodeMessageField 1
+  dotProto = undefined
+
+data PingResponse = PingResponse
+  { status :: Text
+  , hostname :: Text
+  , timestamp :: Text
+  , sha :: Text
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message PingResponse where
+  encodeMessage _ PingResponse{..} = mconcat
+    [ encodeMessageField 1 status
+    , encodeMessageField 2 hostname
+    , encodeMessageField 3 timestamp
+    , encodeMessageField 4 sha
+    ]
+  decodeMessage _ = PingResponse
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+    <*> at decodeMessageField 4
+  dotProto = undefined
+
+data ParseTreeRequest = ParseTreeRequest
+  { blobs :: Vector Blob
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message ParseTreeRequest where
+  encodeMessage _ ParseTreeRequest{..} = mconcat
+    [ encodeMessageField 1 (NestedVec blobs)
+    ]
+  decodeMessage _ = ParseTreeRequest
+    <$> (nestedvec <$> at decodeMessageField 1)
+  dotProto = undefined
+
+data ParseTreeSymbolResponse = ParseTreeSymbolResponse
+  { files :: Vector File
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message ParseTreeSymbolResponse where
+  encodeMessage _ ParseTreeSymbolResponse{..} = mconcat
+    [ encodeMessageField 1 (NestedVec files)
+    ]
+  decodeMessage _ = ParseTreeSymbolResponse
+    <$> (nestedvec <$> at decodeMessageField 1)
+  dotProto = undefined
+
+data ParseTreeGraphResponse = ParseTreeGraphResponse
+  { files :: Vector ParseTreeFileGraph
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message ParseTreeGraphResponse where
+  encodeMessage _ ParseTreeGraphResponse{..} = mconcat
+    [ encodeMessageField 1 (NestedVec files)
+    ]
+  decodeMessage _ = ParseTreeGraphResponse
+    <$> (nestedvec <$> at decodeMessageField 1)
+  dotProto = undefined
+
+data ParseTreeFileGraph = ParseTreeFileGraph
+  { path :: Text
+  , language :: Language
+  , vertices :: Vector TermVertex
+  , edges :: Vector TermEdge
+  , errors :: Vector ParseError
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message ParseTreeFileGraph where
+  encodeMessage _ ParseTreeFileGraph{..} = mconcat
+    [ encodeMessageField 1 path
+    , encodeMessageField 2 language
+    , encodeMessageField 3 (NestedVec vertices)
+    , encodeMessageField 4 (NestedVec edges)
+    , encodeMessageField 5 (NestedVec errors)
+    ]
+  decodeMessage _ = ParseTreeFileGraph
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> (nestedvec <$> at decodeMessageField 3)
+    <*> (nestedvec <$> at decodeMessageField 4)
+    <*> (nestedvec <$> at decodeMessageField 5)
+  dotProto = undefined
+
+data TermEdge = TermEdge
+  { source :: Int64
+  , target :: Int64
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message TermEdge where
+  encodeMessage _ TermEdge{..} = mconcat
+    [ encodeMessageField 1 source
+    , encodeMessageField 2 target
+    ]
+  decodeMessage _ = TermEdge
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data TermVertex = TermVertex
+  { vertexId :: Int64
+  , term :: Text
+  , span :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message TermVertex where
+  encodeMessage _ TermVertex{..} = mconcat
+    [ encodeMessageField 1 vertexId
+    , encodeMessageField 2 term
+    , encodeMessageField 3 (Nested span)
+    ]
+  decodeMessage _ = TermVertex
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+  dotProto = undefined
+
+data ParseError = ParseError
+  { error :: Text
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message ParseError where
+  encodeMessage _ ParseError{..} = mconcat
+    [ encodeMessageField 1 error
+    ]
+  decodeMessage _ = ParseError
+    <$> at decodeMessageField 1
+  dotProto = undefined
+
+data DiffTreeRequest = DiffTreeRequest
+  { blobs :: Vector BlobPair
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DiffTreeRequest where
+  encodeMessage _ DiffTreeRequest{..} = mconcat
+    [ encodeMessageField 1 (NestedVec blobs)
+    ]
+  decodeMessage _ = DiffTreeRequest
+    <$> (nestedvec <$> at decodeMessageField 1)
+  dotProto = undefined
+
+data DiffTreeTOCResponse = DiffTreeTOCResponse
+  { files :: Vector TOCSummaryFile
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DiffTreeTOCResponse where
+  encodeMessage _ DiffTreeTOCResponse{..} = mconcat
+    [ encodeMessageField 1 (NestedVec files)
+    ]
+  decodeMessage _ = DiffTreeTOCResponse
+    <$> (nestedvec <$> at decodeMessageField 1)
+  dotProto = undefined
+
+data TOCSummaryFile = TOCSummaryFile
+  { path :: Text
+  , language :: Language
+  , changes :: Vector TOCSummaryChange
+  , errors :: Vector TOCSummaryError
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message TOCSummaryFile where
+  encodeMessage _ TOCSummaryFile{..} = mconcat
+    [ encodeMessageField 1 path
+    , encodeMessageField 2 language
+    , encodeMessageField 3 (NestedVec changes)
+    , encodeMessageField 4 (NestedVec errors)
+    ]
+  decodeMessage _ = TOCSummaryFile
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> (nestedvec <$> at decodeMessageField 3)
+    <*> (nestedvec <$> at decodeMessageField 4)
+  dotProto = undefined
+
+data TOCSummaryChange = TOCSummaryChange
+  { category :: Text
+  , term :: Text
+  , span :: Maybe Span
+  , changeType :: ChangeType
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message TOCSummaryChange where
+  encodeMessage _ TOCSummaryChange{..} = mconcat
+    [ encodeMessageField 1 category
+    , encodeMessageField 2 term
+    , encodeMessageField 3 (Nested span)
+    , encodeMessageField 4 changeType
+    ]
+  decodeMessage _ = TOCSummaryChange
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+    <*> at decodeMessageField 4
+  dotProto = undefined
+
+data TOCSummaryError = TOCSummaryError
+  { error :: Text
+  , span :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message TOCSummaryError where
+  encodeMessage _ TOCSummaryError{..} = mconcat
+    [ encodeMessageField 1 error
+    , encodeMessageField 2 (Nested span)
+    ]
+  decodeMessage _ = TOCSummaryError
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data DiffTreeGraphResponse = DiffTreeGraphResponse
+  { files :: Vector DiffTreeFileGraph
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DiffTreeGraphResponse where
+  encodeMessage _ DiffTreeGraphResponse{..} = mconcat
+    [ encodeMessageField 1 (NestedVec files)
+    ]
+  decodeMessage _ = DiffTreeGraphResponse
+    <$> (nestedvec <$> at decodeMessageField 1)
+  dotProto = undefined
+
+data DiffTreeFileGraph = DiffTreeFileGraph
+  { path :: Text
+  , language :: Language
+  , vertices :: Vector DiffTreeVertex
+  , edges :: Vector DiffTreeEdge
+  , errors :: Vector ParseError
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DiffTreeFileGraph where
+  encodeMessage _ DiffTreeFileGraph{..} = mconcat
+    [ encodeMessageField 1 path
+    , encodeMessageField 2 language
+    , encodeMessageField 3 (NestedVec vertices)
+    , encodeMessageField 4 (NestedVec edges)
+    , encodeMessageField 5 (NestedVec errors)
+    ]
+  decodeMessage _ = DiffTreeFileGraph
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> (nestedvec <$> at decodeMessageField 3)
+    <*> (nestedvec <$> at decodeMessageField 4)
+    <*> (nestedvec <$> at decodeMessageField 5)
+  dotProto = undefined
+
+data DiffTreeEdge = DiffTreeEdge
+  { source :: Int64
+  , target :: Int64
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DiffTreeEdge where
+  encodeMessage _ DiffTreeEdge{..} = mconcat
+    [ encodeMessageField 1 source
+    , encodeMessageField 2 target
+    ]
+  decodeMessage _ = DiffTreeEdge
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data DiffTreeVertexDiffTerm
+  = Deleted { deleted :: Maybe DeletedTerm }
+  | Inserted { inserted :: Maybe InsertedTerm }
+  | Replaced { replaced :: Maybe ReplacedTerm }
+  | Merged { merged :: Maybe MergedTerm }
+  deriving stock (Eq, Ord, Show, Generic)
+  deriving anyclass (Message, Named, FromJSON, ToJSON)
+
+data DiffTreeVertex = DiffTreeVertex
+  { diffVertexId :: Int64
+  , diffTerm :: Maybe DiffTreeVertexDiffTerm
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DiffTreeVertex where
+  encodeMessage _ DiffTreeVertex{..} = mconcat
+    [ encodeMessageField 1 diffVertexId
+    , case diffTerm of
+         Nothing -> mempty
+         Just (Deleted deleted) -> encodeMessageField 2 deleted
+         Just (Inserted inserted) -> encodeMessageField 3 inserted
+         Just (Replaced replaced) -> encodeMessageField 4 replaced
+         Just (Merged merged) -> encodeMessageField 5 merged
+    ]
+  decodeMessage _ = DiffTreeVertex
+    <$> at decodeMessageField 1
+    <*> oneof
+         Nothing
+         [ (2, Just . Deleted <$> decodeMessageField)
+         , (3, Just . Inserted <$> decodeMessageField)
+         , (4, Just . Replaced <$> decodeMessageField)
+         , (5, Just . Merged <$> decodeMessageField)
+         ]
+  dotProto = undefined
+
+data DeletedTerm = DeletedTerm
+  { term :: Text
+  , span :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message DeletedTerm where
+  encodeMessage _ DeletedTerm{..} = mconcat
+    [ encodeMessageField 1 term
+    , encodeMessageField 2 (Nested span)
+    ]
+  decodeMessage _ = DeletedTerm
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data InsertedTerm = InsertedTerm
+  { term :: Text
+  , span :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message InsertedTerm where
+  encodeMessage _ InsertedTerm{..} = mconcat
+    [ encodeMessageField 1 term
+    , encodeMessageField 2 (Nested span)
+    ]
+  decodeMessage _ = InsertedTerm
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data ReplacedTerm = ReplacedTerm
+  { beforeTerm :: Text
+  , beforeSpan :: Maybe Span
+  , afterTerm :: Text
+  , afterSpan :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message ReplacedTerm where
+  encodeMessage _ ReplacedTerm{..} = mconcat
+    [ encodeMessageField 1 beforeTerm
+    , encodeMessageField 2 (Nested beforeSpan)
+    , encodeMessageField 3 afterTerm
+    , encodeMessageField 4 (Nested afterSpan)
+    ]
+  decodeMessage _ = ReplacedTerm
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+    <*> at decodeMessageField 4
+  dotProto = undefined
+
+data MergedTerm = MergedTerm
+  { term :: Text
+  , beforeSpan :: Maybe Span
+  , afterSpan :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message MergedTerm where
+  encodeMessage _ MergedTerm{..} = mconcat
+    [ encodeMessageField 1 term
+    , encodeMessageField 2 (Nested beforeSpan)
+    , encodeMessageField 3 (Nested afterSpan)
+    ]
+  decodeMessage _ = MergedTerm
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+  dotProto = undefined
+
+data Blob = Blob
+  { content :: Text
+  , path :: Text
+  , language :: Language
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message Blob where
+  encodeMessage _ Blob{..} = mconcat
+    [ encodeMessageField 1 content
+    , encodeMessageField 2 path
+    , encodeMessageField 3 language
+    ]
+  decodeMessage _ = Blob
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+  dotProto = undefined
+
+data BlobPair = BlobPair
+  { before :: Maybe Blob
+  , after :: Maybe Blob
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message BlobPair where
+  encodeMessage _ BlobPair{..} = mconcat
+    [ encodeMessageField 1 (Nested before)
+    , encodeMessageField 2 (Nested after)
+    ]
+  decodeMessage _ = BlobPair
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data File = File
+  { path :: Text
+  , language :: Language
+  , symbols :: Vector Symbol
+  , errors :: Vector ParseError
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message File where
+  encodeMessage _ File{..} = mconcat
+    [ encodeMessageField 1 path
+    , encodeMessageField 2 language
+    , encodeMessageField 3 (NestedVec symbols)
+    , encodeMessageField 4 (NestedVec errors)
+    ]
+  decodeMessage _ = File
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> (nestedvec <$> at decodeMessageField 3)
+    <*> (nestedvec <$> at decodeMessageField 4)
+  dotProto = undefined
+
+data Symbol = Symbol
+  { symbol :: Text
+  , kind :: Text
+  , line :: Text
+  , span :: Maybe Span
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message Symbol where
+  encodeMessage _ Symbol{..} = mconcat
+    [ encodeMessageField 1 symbol
+    , encodeMessageField 2 kind
+    , encodeMessageField 3 line
+    , encodeMessageField 4 (Nested span)
+    ]
+  decodeMessage _ = Symbol
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+    <*> at decodeMessageField 3
+    <*> at decodeMessageField 4
+  dotProto = undefined
+
+data Position = Position
+  { line :: Int64
+  , column :: Int64
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message Position where
+  encodeMessage _ Position{..} = mconcat
+    [ encodeMessageField 1 line
+    , encodeMessageField 2 column
+    ]
+  decodeMessage _ = Position
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data Span = Span
+  { start :: Maybe Position
+  , end :: Maybe Position
+  } deriving stock (Eq, Ord, Show, Generic)
+    deriving anyclass (Named, FromJSON, ToJSON)
+
+instance Message Span where
+  encodeMessage _ Span{..} = mconcat
+    [ encodeMessageField 1 (Nested start)
+    , encodeMessageField 2 (Nested end)
+    ]
+  decodeMessage _ = Span
+    <$> at decodeMessageField 1
+    <*> at decodeMessageField 2
+  dotProto = undefined
+
+data ChangeType
+  = None
+  | Added
+  | Removed
+  | Modified
+  deriving stock (Eq, Ord, Show, Enum, Bounded, Generic)
+  deriving anyclass (Named, MessageField, FromJSON, ToJSON)
+  deriving Primitive via PrimitiveEnum ChangeType
+instance HasDefault ChangeType where def = None
+
+data Language
+  = Unknown
+  | Go
+  | Haskell
+  | Java
+  | Javascript
+  | Json
+  | Jsx
+  | Markdown
+  | Python
+  | Ruby
+  | Typescript
+  | Php
+  deriving stock (Eq, Ord, Show, Enum, Bounded, Generic)
+  deriving anyclass (Named, MessageField, FromJSON, ToJSON)
+  deriving Primitive via PrimitiveEnum Language
+instance HasDefault Language where def = Unknown
diff --git a/src/Semantic/CLI.hs b/src/Semantic/CLI.hs
index 39921d347..142a9bf4d 100644
--- a/src/Semantic/CLI.hs
+++ b/src/Semantic/CLI.hs
@@ -10,7 +10,7 @@ import           Data.Handle
 import           Data.Project
 import           Options.Applicative hiding (style)
 import           Prologue
-import           Semantic.API hiding (File)
+import           Semantic.Api hiding (File)
 import qualified Semantic.AST as AST
 import           Semantic.Config
 import qualified Semantic.Graph as Graph
diff --git a/test/Examples.hs b/test/Examples.hs
index e15a1d94f..2855a33d8 100644
--- a/test/Examples.hs
+++ b/test/Examples.hs
@@ -17,7 +17,7 @@ import           Data.Quieterm
 import           Data.Typeable (cast)
 import           Data.Void
 import           Parsing.Parser
-import           Semantic.API (TermOutputFormat (..), parseTermBuilder)
+import           Semantic.Api (TermOutputFormat (..), parseTermBuilder)
 import           Semantic.Config (Config (..), Options (..), defaultOptions)
 import qualified Semantic.IO as IO
 import           Semantic.Task
diff --git a/test/Rendering/TOC/Spec.hs b/test/Rendering/TOC/Spec.hs
index 3b3b29a4d..4630ef7ca 100644
--- a/test/Rendering/TOC/Spec.hs
+++ b/test/Rendering/TOC/Spec.hs
@@ -24,7 +24,7 @@ import qualified Data.Syntax as Syntax
 import qualified Data.Syntax.Declaration as Declaration
 import Rendering.TOC
 import Semantic.Config
-import Semantic.API (diffSummaryBuilder)
+import Semantic.Api (diffSummaryBuilder)
 import Serializing.Format as Format
 
 import SpecHelpers
diff --git a/test/Semantic/CLI/Spec.hs b/test/Semantic/CLI/Spec.hs
index 1217896d9..2f6119109 100644
--- a/test/Semantic/CLI/Spec.hs
+++ b/test/Semantic/CLI/Spec.hs
@@ -4,7 +4,7 @@ import           Control.Monad (when)
 import qualified Data.ByteString as B
 import           Data.ByteString.Builder
 import           Data.Foldable (for_)
-import           Semantic.API hiding (File, Blob, BlobPair)
+import           Semantic.Api hiding (File, Blob, BlobPair)
 import           Semantic.CLI
 import           Semantic.IO
 import           Semantic.Task
diff --git a/test/Semantic/Spec.hs b/test/Semantic/Spec.hs
index 65e4f4130..a6f5674de 100644
--- a/test/Semantic/Spec.hs
+++ b/test/Semantic/Spec.hs
@@ -2,7 +2,7 @@ module Semantic.Spec (spec) where
 
 import Data.Diff
 import Data.Patch
-import Semantic.API hiding (Blob)
+import Semantic.Api hiding (Blob)
 import System.Exit
 
 import SpecHelpers
diff --git a/test/SpecHelpers.hs b/test/SpecHelpers.hs
index f2df8479b..5c8d48960 100644
--- a/test/SpecHelpers.hs
+++ b/test/SpecHelpers.hs
@@ -82,7 +82,7 @@ import Data.Set (Set)
 import qualified Semantic.IO as IO
 import Semantic.Config (Config(..), optionsLogLevel)
 import Semantic.Telemetry (LogQueue, StatQueue)
-import Semantic.API hiding (File, Blob, BlobPair)
+import Semantic.Api hiding (File, Blob, BlobPair)
 import System.Exit (die)
 import Control.Exception (displayException)