---
title: "Deploy Mercure"
description: "Mercure 1.0 real-time SSE hub for pushing updates to browsers and apps."
category: "Queues"
url: https://railway.com/deploy/mercure
---

# Deploy Mercure

Mercure 1.0 real-time SSE hub for pushing updates to browsers and apps.

**[Deploy Mercure on Railway](https://railway.com/template/mercure)**

Machine-readable deploy manifest (JSON, validated by TemplateCI): https://railway.com/deploy/mercure/manifest.json

- **Creator:** Agaz Self-Host
- **Category:** Queues

## Template content

### mercure https://mercure.rocks/icon.svg

- **Image:** dunglas/mercure:v1.0.0
- **Health check:** /
- **Public domain:** Yes

## Documentation

# Deploy and Host Mercure on Railway

Mercure is an open protocol and hub for pushing real-time updates from servers to browsers and apps over Server-Sent Events. Your backend publishes an update to a topic with a signed token, and subscribed clients receive it instantly, with automatic reconnection, history replay and authorization built into the protocol.

## About Hosting Mercure

This template deploys the Mercure.rocks hub v1.0.0, the first stable release, on Caddy with the bolt transport stored on a Railway volume so history survives restarts. Publishers and subscribers authenticate with OAuth 2.0-style access tokens signed with the two generated keys. The token issuer and audience are pinned to your Railway domain, which avoids the `http` versus `https` mismatch behind Railway's proxy. The safe debugger UI is enabled; the insecure playground is not. Add your frontend origin to `cors_origins` before subscribing from another domain. Everything runs in one small service that fits the Hobby plan.

## Common Use Cases

- Live updates for dashboards, notifications and collaborative apps without WebSocket servers
- Pushing API resource changes to clients (API Platform, Symfony, Laravel and any backend)
- Streaming job progress or AI responses to the browser over SSE

## Dependencies for Mercure Hosting

- `dunglas/mercure:v1.0.0` (official image, Caddy based)
- A Railway volume at `/data` for the bolt history database

### Deployment Dependencies

- [Mercure documentation](https://mercure.rocks/docs)
- [Mercure v1.0.0 release notes](https://github.com/dunglas/mercure/releases/tag/v1.0.0)
- [Upgrade guide to 1.0](https://mercure.rocks/docs/1.0/UPGRADE)
- [Railway volumes](https://docs.railway.com/reference/volumes)

### Implementation Details

| Service | Image | Networking | Storage |
| --- | --- | --- | --- |
| mercure | `dunglas/mercure:v1.0.0` | public domain on 80; private | volume at `/data` |

Tokens are JWTs (HS256) with `typ: at+jwt`, `iss` equal to `MERCURE_TRUSTED_ISSUERS`, `aud` equal to `https:///.well-known/mercure`, an `exp`, and an `authorization_details` array:

```json
{"authorization_details": [{"type": "https://mercure.rocks/authorization-detail",
  "actions": ["publish"], "topics": [{"match": "https://example.com/books/1"}]}]}
```

Sign publisher tokens with `MERCURE_PUBLISHER_JWT_KEY` and subscriber tokens with `MERCURE_SUBSCRIBER_JWT_KEY`, then publish:

```bash
curl -X POST "$MERCURE_HUB_URL" -H "Authorization: Bearer " \
  -d "topic=https://example.com/books/1" -d 'data={"status":"shipped"}'
```

| Variable | Default | Purpose |
| --- | --- | --- |
| `MERCURE_PUBLISHER_JWT_KEY` / `MERCURE_SUBSCRIBER_JWT_KEY` | generated | HMAC keys for access tokens |
| `MERCURE_TRUSTED_ISSUERS` | `https://` | Required `iss` claim |
| `MERCURE_EXTRA_DIRECTIVES` | resource identifier, debugger, bolt on `/data` | Hub directives; add `cors_origins https://your.app` here |

Notes:

- The 0.x `mercure` JWT claim is no longer accepted; mint tokens in the 1.0 format above.
- `cors_origins *` is not allowed together with authenticated subscribers; list your origins explicitly.
- Anonymous subscribers are off. Add `anonymous` to the extra directives only for topics you want public.

This is a community-maintained deployment package and does not imply affiliation with or endorsement by the Mercure project or its maintainers.

## Why Deploy Mercure on Railway?

Railway is a singular platform to deploy your infrastructure stack. Railway will host your infrastructure so you don't have to deal with configuration, while allowing you to vertically and horizontally scale it.

By deploying Mercure on Railway, you are one step closer to supporting a complete full-stack application with minimal burden. Host your servers, databases, AI agents, and more on Railway.


## Similar templates

- [smoothmq](https://railway.com/deploy/AJv-64) — A drop-in replacement for AWS SQS
- [Kafka UI](https://railway.com/deploy/kafka-ui) — Kafbat UI — Open-source web UI to monitor and manage Apache Kafka clusters
- [NATS + JetStream](https://railway.com/deploy/nats-jetstream) — An open source messaging system that promises at-most-once delivery.

Open this page in a browser: https://railway.com/deploy/mercure