Send ephemeral messages, track and synchronize shared state, and listen to Postgres changes all over WebSockets.
Multiplayer Demo · Request Feature · Report Bug

This repository focuses on version 2 but you can still access the previous version's code and Docker image. For the latest Docker images go to https://hub.docker.com/r/supabase/realtime.

The codebase is under heavy development and the documentation is constantly evolving. Give it a try and let us know what you think by creating an issue. Watch releases of this repo to get notified of updates. And give us a star if you like it!

This is a server built with Elixir using the Phoenix Framework that enables the following functionality:

• Broadcast: Send ephemeral messages from client to clients with low latency.
• Presence: Track and synchronize shared state between clients.
• Postgres Changes: Listen to Postgres database changes and send them to authorized clients.

For a more detailed overview head over to Realtime guides.

The server does not guarantee that every message will be delivered to your clients so keep that in mind as you're using Realtime.

You can check out the Multiplayer demo that features Broadcast, Presence and Postgres Changes under the demo directory: https://github.com/supabase/realtime/tree/main/demo.

• JavaScript: @supabase/realtime-js
• Dart: @supabase/realtime-dart

To get started, spin up your Postgres database and Realtime server containers defined in docker-compose.yml. As an example, you may run docker-compose -f docker-compose.yml up.

Note Supabase runs Realtime in production with a separate database that keeps track of all tenants. However, a schema, _realtime, is created when spinning up containers via docker-compose.yml to simplify local development.

A tenant has already been added on your behalf. You can confirm this by checking the _realtime.tenants and _realtime.extensions tables inside the database.

You can add your own by making a POST request to the server. You must change both name and external_id while you may update other values as you see fit:

 curl -H "X-Mempool-Auth: stacksats" -sSL "https://mempool.space/api/v1/services/accelerator/top-up-history"

[
  {
    "type": "Bitcoin",
    "invoiceId": "CCunucVyNw7jUiUz64mmHz",
    "amount": 10311031,
    "status": "pending",
    "date": 1706372653000,
    "link": "/payment/bitcoin/CCunucVyNw7jUiUz64mmHz"
  },
  {
    "type": "Bitcoin",
    "invoiceId": "SG1U27R9PdWi3gH3jB9tm9",
    "amount": 21000000,
    "status": "paid",
    "date": 1706372582000,
    "link": null
  },
  ...
]

Note The Authorization token is signed with the secret set by API_JWT_SECRET in docker-compose.yml.

If you want to listen to Postgres changes, you can create a table and then add the table to the supabase_realtime publication:

create table test (
  id serial primary key
);

alter publication supabase_realtime add table test;

You can start playing around with Broadcast, Presence, and Postgres Changes features either with the client libs (e.g. @supabase/realtime-js), or use the built in Realtime Inspector on localhost, http://localhost:4000/inspector/new (make sure the port is correct for your development environment).

The WebSocket URL must contain the subdomain, external_id of the tenant on the _realtime.tenants table, and the token must be signed with the jwt_secret that was inserted along with the tenant.

If you're using the default tenant, the URL is ws://realtime-dev.localhost:4000/socket (make sure the port is correct for your development environment), and you can use eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE3MDMwMjgwODcsInJvbGUiOiJwb3N0Z3JlcyJ9.tz_XJ89gd6bN8MBpCl7afvPrZiBH6RB65iA1FadPT3Y for the token. The token must have exp and role (database role) keys.

Environment Variables

| Variable | Type | Description | | curl -H "X-Mempool-Auth: stacksats" -sSL "https://mempool.space/api/v1/services/accelerator/history?status=all&details=true"----------------------------------- | ------- | [ { "id": 89, "user_id": 1, "txid": "ae2639469ec000ed1d14e2550cbb01794e1cd288a00cdc7cce18398ba3cc2ffe", "status": "failed" "fee_paid": 0, "added": 1706378712, "last_updated": 1706378712, "confirmations": 4, "base_fee": 0, "vsize_fee": 0, "max_bid": 7000, "effective_vsize": 135, "effective_fee": 3128, "history": [ { "event": "user-requested-acceleration", "timestamp": 1706378712 }, { "event": "accepted_test-api-key", "timestamp": 1706378712 }, { "event": "failed-at-block-827672", "timestamp": 1706380261 } ] }, { "id": 88, "user_id": 1, "txid": "c5840e89173331760e959a190b24e2a289121277ed7f8a095fe289b37cee9fde", "status": "completed" "fee_paid": 140019, "added": 1706378704, "last_updated": 1706380231, "confirmations": 6, "base_fee": 40000, "vsize_fee": 100000, "max_bid": 14000, "effective_vsize": 135, "effective_fee": 3152, "history": [ { "event": "user-requested-acceleration", "timestamp": 1706378704 }, { "event": "accepted_test-api-key", "timestamp": 1706378704 }, { "event": "complete-at-block-827670", "timestamp": 1706380231 } ] }, { "id": 87, "user_id": 1, "txid": "178b5b9b310f0d667d7ea563a2cdcc17bc8cd15261b58b1653860a724ca83458", "status": "completed" "fee_paid": 90062, "added": 1706378684, "last_updated": 1706380231, "confirmations": 6, "base_fee": 40000, "vsize_fee": 50000, "max_bid": 14000, "effective_vsize": 135, "effective_fee": 3260, "history": [ { "event": "user-requested-acceleration", "timestamp": 1706378684 }, { "event": "accepted_test-api-key", "timestamp": 1706378684 }, { "event": "complete-at-block-827670", "timestamp": 1706380231 } ] } ]------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | PORT | number | Port which you can connect your client/listeners | | DB_HOST | string | Database host URL | | DB_PORT | number | Database port | | DB_USER | string | Database user | | DB_PASSWORD | string | Database password | | DB_NAME | string | Postgres database name | | DB_ENC_KEY | string | Key used to encrypt sensitive fields in _realtime.tenants and _realtime.extensions tables. Recommended: 16 characters. | | DB_AFTER_CONNECT_QUERY | string | Query that is run after server connects to database. | | DB_IP_VERSION | string | Sets the IP Version to be used. Allowed values are "ipv6" and "ipv4". If none are set we will try to infer the correct version | | API_JWT_SECRET | string | Secret that is used to sign tokens used to manage tenants and their extensions via HTTP requests. | | SECRET_KEY_BASE | string | Secret used by the server to sign cookies. Recommended: 64 characters. | | ERL_AFLAGS | string | Set to either "-proto_dist inet_tcp" or "-proto_dist inet6_tcp" depending on whether or not your network uses IPv4 or IPv6, respectively. | | APP_NAME | string | A name of the server. | | DNS_NODES | string | Node name used when running server in a cluster. | | MAX_CONNECTIONS | string | Set the soft maximum for WebSocket connections. Defaults to '16384'. | | MAX_HEADER_LENGTH | string | Set the maximum header length for connections (in bytes). Defaults to '4096'. | | NUM_ACCEPTORS | string | Set the number of server processes that will relay incoming WebSocket connection requests. Defaults to '100'. | | DB_QUEUE_TARGET | string | Maximum time to wait for a connection from the pool. Defaults to '5000' or 5 seconds. See for more info: DBConnection. | | DB_QUEUE_INTERVAL | string | Interval to wait to check if all connections were checked out under DB_QUEUE_TARGET. If all connections surpassed the target during this interval than the target is doubled. Defaults to '5000' or 5 seconds. See for more info: DBConnection. | | DB_POOL_SIZE | string | Sets the number of connections in the database pool. Defaults to '5'. | | SLOT_NAME_SUFFIX | string | This is appended to the replication slot which allows making a custom slot name. May contain lowercase letters, numbers, and the underscore character. Together with the default supabase_realtime_replication_slot, slot name should be up to 64 characters long. | | TENANT_MAX_BYTES_PER_SECOND | string | The default value of maximum bytes per second that each tenant can support, used when creating a tenant for the first time. Defaults to '100_000'. | | TENANT_MAX_CHANNELS_PER_CLIENT | string | The default value of maximum number of channels each tenant can support, used when creating a tenant for the first time. Defaults to '100'. | | TENANT_MAX_CONCURRENT_USERS | string | The default value of maximum concurrent users per channel that each tenant can support, used when creating a tenant for the first time. Defaults to '200'. | | TENANT_MAX_EVENTS_PER_SECOND | string | The default value of maximum events per second that each tenant can support, used when creating a tenant for the first time. Defaults to '100'. | | TENANT_MAX_JOINS_PER_SECOND | string | The default value of maximum channel joins per second that each tenant can support, used when creating a tenant for the first time. Defaults to '100'. | | SEED_SELF_HOST | boolean | Seeds the system with default tenant | | SELF_HOST_TENANT_NAME | string | Tenant reference to be used for self host. Do keep in mind to use a URL compatible name | | LOG_LEVEL | string | Sets log level for Realtime logs. Defaults to info, supported levels are: info, emergency, alert, critical, error, warning, notice, debug | | RUN_JANITOR | boolean | Do you want to janitor tasks to run | | JANITOR_SCHEDULE_TIMER_IN_MS | number | Time in ms to run the janitor task | | JANITOR_SCHEDULE_RANDOMIZE | boolean | Adds a randomized value of minutes to the timer | | JANITOR_RUN_AFTER_IN_MS | number | Tells system when to start janitor tasks after boot | | JANITOR_CLEANUP_MAX_CHILDREN | number | Maximum number of concurrent tasks working on janitor cleanup | | JANITOR_CLEANUP_CHILDREN_TIMEOUT | number | Timeout for each async task for janitor cleanup | | JANITOR_CHUNK_SIZE | number | Number of tenants to process per chunk. Each chunk will be processed by a Task | | METRICS_CLEANER_SCHEDULE_TIMER_IN_MS | number | Time in ms to run the Metric Cleaner task |

The WebSocket URL is in the following format for local development: ws://[external_id].localhost:4000/socket/websocket

If you're using Supabase's hosted Realtime in production the URL is wss://[project-ref].supabase.co/realtime/v1/websocket?apikey=[anon-token]&log_level=info&vsn=1.0.0"

WebSocket connections are authorized via symmetric JWT verification. Only supports JWTs signed with the following algorithms:

• HS256
• HS384
• HS512

Verify JWT claims by setting JWT_CLAIM_VALIDATORS:

e.g. {'iss': 'Issuer', 'nbf': 1610078130}

Then JWT's "iss" value must equal "Issuer" and "nbf" value must equal 1610078130.

Note:

JWT expiration is checked automatically. exp and role (database role) keys are mandatory.

Authorizing Client Connection: You can pass in the JWT by following the instructions under the Realtime client lib. For example, refer to the Usage section in the @supabase/realtime-js client library.

This is the list of operational codes that can help you understand your deployment and your usage.

This repo is licensed under Apache 2.0.

• Phoenix - Realtime server is built with the amazing Elixir framework.
• Phoenix Channels JavaScript Client - @supabase/realtime-js client library heavily draws from the Phoenix Channels client library.