graphql-engine/README.md

# Hasura GraphQL Engine

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Hasura GraphQL Engine is a blazing-fast GraphQL server that gives you **instant, realtime GraphQL APIs over Postgres**, with [**webhook triggers**](event-triggers.md) on database events for asynchronous business logic.

Hasura helps you build GraphQL apps backed by Postgres or incrementally move to GraphQL for existing applications using Postgres.

Read more at [hasura.io](https://hasura.io) and the [docs](https://docs.hasura.io). 

------------------

![Hasura GraphQL Engine Demo](assets/demo.gif)

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![Hasura GraphQL Engine Realtime Demo](assets/realtime.gif)

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## Features

* **Make powerful queries**: Built-in filtering, pagination, pattern search, bulk insert, update, delete mutations
* **Realtime**: Convert any GraphQL query to a live query by using subscriptions
* **Trigger webhooks or serverless functions**: On Postgres insert/update/delete events ([read more](event-triggers.md))
* **Works with existing, live databases**: Point it to an existing Postgres database to instantly get a ready-to-use GraphQL API
* **Fine-grained access control**: Dynamic access control that integrates with your auth system (eg: auth0, firebase-auth)
* **High-performance & low-footprint**: ~15MB docker image; ~50MB RAM @ 1000 req/s; multi-core aware
* **Admin UI & Migrations**: Admin UI & Rails-inspired schema migrations
* **Postgres** ❤️: Supports Postgres types (PostGIS/geo-location, etc.), turns views to *graphs*, trigger stored functions or procedures with mutations

Read more at: [https://hasura.io](https://hasura.io) and the [docs](https://docs.hasura.io).

## Table of contents
<!-- markdown-toc start - Don't edit this section. Run M-x markdown-toc-refresh-toc -->
**Table of Contents**

- [Quickstart:](#quickstart)
    - [One-click deployment on Heroku](#one-click-deployment-on-heroku)
    - [Other deployment methods](#other-deployment-methods)
- [Architecture](#architecture)
- [Client-side tooling](#client-side-tooling)
- [Add business logic](#add-business-logic)
    - [Custom resolvers](#custom-resolvers)
    - [Trigger webhooks on database events](#trigger-webhooks-on-database-events)
- [Demos](#demos)
    - [Realtime applications](#realtime-applications)
    - [Videos](#videos)
- [Support & Troubleshooting](#support--troubleshooting)
- [Contributing](#contributing)
- [Brand assets](#brand-assets)
- [License](#license)

<!-- markdown-toc end -->

## Quickstart: 

### One-click deployment on Heroku

The fastest way to try Hasura out is via Heroku.

1. Click on the following button to deploy GraphQL Engine on Heroku with the free Postgres add-on:

    [![Deploy to Heroku](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/hasura/graphql-engine-heroku)

2. Open the Hasura console

   Visit `https://<app-name>.herokuapp.com` (*replace \<app-name\> with your app name*) to open the admin console.

3. Make your first GraphQL query

   Create a table and instantly run your first query. Follow this [simple guide](https://docs.hasura.io/1.0/graphql/manual/getting-started/first-graphql-query.html).

### Other deployment methods

For Docker-based deployment and advanced configuration options, see [deployment
guides](https://docs.hasura.io/1.0/graphql/manual/getting-started/index.html) or
[install manifests](install-manifests).

## Architecture

The Hasura GraphQL Engine fronts a Postgres database instance and can accept GraphQL requests from your client apps. It can be configured to work with your existing auth system and can handle access control using field-level rules with dynamic variables from your auth system.

You can also place the engine behind a central GraphQL proxy that fronts multiple GraphQL APIs via schema stitching.

![Hasura GraphQL Engine architecture](assets/hasura-arch.svg)

## Client-side tooling

Hasura works with any GraphQL client. We recommend using [Apollo Client](https://github.com/apollographql/apollo-client). See [awesome-graphql](https://github.com/chentsulin/awesome-graphql) for a list of clients.

## Add business logic

### Custom resolvers

Add custom resolvers in addition to Hasura GraphQL engine. Ideal for delegating
to HTTP APIs, making direct calls to another data-source or writing business
logic in code - [read more](community/boilerplates/custom-resolvers).

### Trigger webhooks on database events

Add asynchronous business logic that is triggered based on database events.
Ideal for notifications, data-pipelines from Postgres or asynchronous
processing - [read more](event-triggers.md).

## Demos

Check out all the example applications in the
[community/examples](community/examples) directory.

### Realtime applications

- Group Chat application built with React, includes a typing indicator, online users & new
  message notifications.
  - [Try it out](https://chat-example-trial-roar.herokuapp.com/)
  - [Tutorial](community/examples/realtime-chat)
  - [Browse APIs](https://hasura-realtime-group-chat.herokuapp.com/)

- Live location tracking app that shows a running vehicle changing current GPS
  coordinates moving on a map. 
  - [Try it out](https://hasura.github.io/realtime-location-app/)
  - [Tutorial](community/examples/realtime-location-tracking)
  - [Browse APIs](https://realtime-backend.herokuapp.com/)

- A realtime dashboard for data aggregations on continuously changing data.
  - [Try it out](https://shahidh.in/hasura-realtime-poll/)
  - [Tutorial](community/examples/realtime-poll)
  - [Browse APIs](https://hasura-realtime-poll.herokuapp.com/)

### Videos

* [Add GraphQL to a self-hosted GitLab instance](https://www.youtube.com/watch?v=a2AhxKqd82Q) (*3:44 mins*)
* [Todo app with Auth0 and GraphQL backend](https://www.youtube.com/watch?v=15ITBYnccgc) (*4:00 mins*)
* [GraphQL on GitLab integrated with GitLab auth](https://www.youtube.com/watch?v=m1ChRhRLq7o) (*4:05 mins*)
* [Dashboard for 10million rides with geo-location (PostGIS, Timescale)](https://www.youtube.com/watch?v=tsY573yyGWA) (*3:06 mins*)


## Support & Troubleshooting

The documentation and community will help you troubleshoot most issues. If you have encountered a bug or need to get in touch with us, you can contact us using one of the following channels:

* Support & feedback: [Discord](https://discord.gg/3FNQnWj)
* Issue & bug tracking: [GitHub issues](https://github.com/hasura/graphql-engine/issues)
* Follow product updates: [@HasuraHQ](https://twitter.com/hasurahq)
* Talk to us on our [website chat](https://hasura.io)

We are committed to fostering an open and welcoming environment in the community. Please see the [Code of Conduct](code-of-conduct.md).

## Contributing

Check out our [contributing guide](CONTRIBUTING.md) for more details.

## Brand assets

Hasura brand assets (logos, the Hasura mascot, powered by badges etc.) can be
found in the [assets/brand](assets/brand) folder. Feel free to use them in your
application/website etc. We'd be thrilled if you add the "Powered by Hasura"
badge to your applications built using Hasura. ❤️

<div style="display: flex;">
  <img src="assets/brand/powered_by_hasura_black.svg" width="150px"/>
  <img src="assets/brand/powered_by_hasura_white.svg" width="150px"/>
</div>

```html
<!-- For light backgrounds -->
<a href="https://hasura.io">
  <img width="150px" src="https://graphql-engine-cdn.hasura.io/img/powered_by_hasura_black.svg" />
</a>

<!-- For dark backgrounds -->
<a href="https://hasura.io">
  <img width="150px" src="https://graphql-engine-cdn.hasura.io/img/powered_by_hasura_white.svg" />
</a>
```

## License

The core GraphQL Engine is available under the [GNU Affero General Public
License v3](https://www.gnu.org/licenses/agpl-3.0.en.html) (AGPL-3.0), the same
license as [MongoDB](https://www.mongodb.com/community/licensing). We have
written more about what you can and cannot do under AGPL
[here](https://github.com/hasura/graphql-engine/wiki/License-Explained). 

**Commercial licenses** that bundle the Hasura GraphQL Engine with support, and
SLAs are available on request. Please feel free to contact us at build@hasura.io
or on our [website chat](https://hasura.io). 

All **other content** (except those in [`server`](server), [`cli`](cli) and
[`console`](console) directories) are under [MIT License](LICENSE-community).
This includes everything in the [`docs`](docs) and [`community`](community)
directories.