Mercure The Mercure protocol

Name: The Mercure protocol API
Brand: The Mercure protocol
Availability: InStock

★ Only Publicly Available OpenAPI DocumentCommunicationsPush Notificationsbearer, apiKey5 EndpointsREST

For Agents

Install Jentic One Beta

Connect the The Mercure protocol to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the The Mercure protocol, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with The Mercure protocol API.

Publish JSON updates to one or more topics for live fan-out to subscribed clients

Subscribe to a Mercure topic stream and receive Server-Sent Events for matching updates

List currently active subscriptions on the hub for monitoring and debugging

GET STARTED

Start building with The Mercure protocol API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI specification for The Mercure protocol, keeping it validated and agent-ready. Mercure is an open protocol built on top of Server-Sent Events for pushing data updates from a server to web browsers and HTTP clients in a fast, battery-efficient way. The hub exposes a single well-known endpoint for publishing JSON-LD updates and subscribing to topics, plus introspection endpoints that report active subscriptions per topic and subscriber, making it a lightweight backbone for live UIs, real-time dashboards, and notification fan-out.

Use Cases

Patterns agents use The Mercure protocol API for, with concrete tasks.

★ Live UI Updates

Web applications can push state changes to every connected browser by POSTing JSON updates to /.well-known/mercure with a topic IRI. Clients subscribe to the same topic via GET on the same path and receive Server-Sent Events. Mercure handles reconnection, last-event-id replay, and HTTP/2 multiplexing, so adding live updates to a SaaS dashboard is typically a few hours of work.

Call POST /.well-known/mercure with topic 'https://example.com/orders/42' and a JSON body to broadcast an order status change.

Notification Fan-Out

Internal tools that need to notify many users about a single event (a deploy, an incident, a chat mention) can publish once to a Mercure topic and let the hub fan out to every subscribed client over Server-Sent Events. This avoids per-user fetch loops and keeps battery and bandwidth use low on mobile clients.

Publish a JSON notification to topic 'https://example.com/incidents' so every subscribed dashboard renders the new alert.

Subscription Monitoring

Operators running a Mercure hub can introspect connected subscribers to debug delivery issues. GET /.well-known/mercure/subscriptions lists all active subscriptions, and the per-topic and per-subscriber endpoints narrow the view to a specific topic or client. This is useful for verifying that a release of a frontend client is actually subscribing to the expected topics.

Call GET /.well-known/mercure/subscriptions/https%3A%2F%2Fexample.com%2Forders%2F42 to see who is currently listening to the orders topic.

Agent-Driven Real-Time Events

An AI agent producing live updates (a long-running build, a multi-step generation job) can publish progress events to a Mercure topic via Jentic, and any frontend or backend subscriber receives them as Server-Sent Events. The agent searches Jentic for the publish operation, loads the schema, and posts updates without writing custom Mercure client code.

Search Jentic for 'publish a Mercure update', load POST /.well-known/mercure, and execute it with the topic and JSON payload describing the agent's progress.

Key Endpoints

5 endpoints — jentic publishes the only available openapi specification for the mercure protocol, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

/.well-known/mercure

Publish an update to one or more topics

GET

/.well-known/mercure

Subscribe to topic updates over SSE

GET

/.well-known/mercure/subscriptions

List active subscriptions on the hub

GET

/.well-known/mercure/subscriptions/{topic}

List subscriptions for a topic

GET

/.well-known/mercure/subscriptions/{topic}/{subscriber}

Inspect a specific subscription

POST

/.well-known/mercure

Publish an update to one or more topics

GET

/.well-known/mercure

Subscribe to topic updates over SSE

GET

/.well-known/mercure/subscriptions

List active subscriptions on the hub

GET

/.well-known/mercure/subscriptions/{topic}

List subscriptions for a topic

GET

/.well-known/mercure/subscriptions/{topic}/{subscriber}

Inspect a specific subscription

Why Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Mercure JWT signing keys are stored in the Jentic vault. Agents call publish and subscription endpoints with a scoped Jentic token, which exchanges to a topic-restricted JWT inside the gateway.

Intent-based discovery

Agents search Jentic with intents like 'publish a real-time update' and Jentic returns POST /.well-known/mercure with the topic and data fields modelled in the schema.

Time to first call

Direct Mercure integration: 1-2 days to wire up JWT issuance, topic routing, and SSE clients. Through Jentic: under an hour for publish-side calls.

FAQs

Specific to using The Mercure protocol API through Jentic.

Why is there no official OpenAPI spec for The Mercure protocol?

Mercure does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call The Mercure protocol via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does The Mercure protocol use?

The hub accepts a JWT bearer token via the standard Authorization header, preferred for server-to-server calls, or a cookie named mercureAuthorization for browsers. JWT claims constrain which topics a publisher can write to and which a subscriber can read. Through Jentic, JWT signing keys live in the credential vault and the agent gets a scoped Jentic token.

Can I publish to multiple topics in a single Mercure call?

Yes. POST /.well-known/mercure accepts repeated topic form fields, so a single update can be delivered to several topic IRIs at once. This is the standard way to fan out one event to multiple groupings, for example a per-user inbox topic plus a global feed topic.

What are the rate limits for The Mercure protocol?

The protocol itself does not define rate limits; these are enforced by the hub deployment. The reference Mercure hub supports thousands of concurrent subscribers per process and limits are set in hub configuration rather than in the spec, so production rollouts should size the hub for peak concurrent SSE connections.

How do I publish a Mercure update through Jentic?

Install the SDK with pip install jentic, search for 'publish a Mercure update', load the POST /.well-known/mercure operation, and execute it with the topic IRI and JSON data. Jentic attaches the JWT and posts to the configured hub URL.

Does Mercure support private updates only some subscribers can read?

Yes. The publish endpoint accepts a private flag and a list of mercure.publish or mercure.subscribe topic selectors in the JWT. The hub only delivers the update to subscribers whose JWT grants them access to the matching topic IRI.

Mercure The Mercure protocol

Connect the The Mercure protocol to your agent

Capabilities

Start building with The Mercure protocol API

Use Cases

Key Endpoints

Why Jentic?

Related APIs

FAQs