What events does Cosmo notify on?

The current event type is FEDERATED_GRAPH_SCHEMA_UPDATED, fired when any schema change updates the federated graph. Additional event types may be added over time.

What does the event payload contain?

Each payload includes the federated graph ID, name, namespace, error status, and an optional actor_id identifying who triggered the event. Payloads are versioned JSON.

Can I have multiple notification channels?

Yes. You can configure multiple webhooks and multiple Slack integrations per organization. Each has its own name, destination, and event subscription.

How do I verify webhook payloads are authentic?

Each webhook request includes an X-Cosmo-Signature-256 header containing an HMAC-SHA256 signature computed with your secret. Verify it in your receiving endpoint before processing the payload.

Can I filter notifications to specific events?

Yes. When configuring a notification channel, you choose which event types it receives. This keeps noise low and lets different teams subscribe to the events relevant to them.

Is there a delivery guarantee or retry mechanism?

Configure multiple webhooks as backup endpoints if you need redundancy, and implement standard retry logic in your receiving infrastructure.

Alerts & Notifications for Federated GraphQL | Cosmo by WunderGraph

The problem

Federation teams miss changes they need to know about

Subgraphs evolve independently. Downstream consumers find out about changes when their integrations break, not before.

Schema changes happen without warning

Multiple teams publish subgraph updates on their own schedules. Downstream consumers have no way to know a change occurred until something breaks.

Manual monitoring is unworkable at scale

Checking the schema registry by hand for each subgraph across multiple namespaces is not sustainable. Teams miss changes. Coordination breaks down.

Generic tools have no federation context

HTTP monitors see traffic, not schema events. They cannot tell you which subgraph changed, whether errors occurred, or who made the change.

Our solution

A notification hub for the whole federated graph

One system handles detection and dispatch. Configure webhooks for programmatic integrations and Slack for team visibility. Each channel gets its own event subscription. Every payload is signed and carries actor attribution.

From event to notification

Cosmo monitors your federated graph for schema changes and other significant events.
When an event occurs, the system dispatches notifications to all configured channels immediately.
Webhooks receive HMAC-SHA256 signed HTTP POST requests with structured JSON payloads.
Slack integrations receive formatted messages directly to your chosen channel via the Slack API.
Each channel has its own event subscription, so different teams receive only the alerts they care about.
Payloads include the federated graph ID, name, namespace, error status, and an optional actor ID for attribution.

Configure once. Every change reaches the right channels automatically.

Alerts & Notifications

Before & After

Before Cosmo	With Cosmo
Manually checking for schema changes across subgraphs	Automatic notifications the moment an event occurs
No visibility into breaking changes until production breaks	Real-time alerts on every schema update with error status
No record of who made a change	Payloads include actor_id for attribution
Knowledge siloed in individual subgraph teams	Organization-wide notification channels for any audience

Notification channels

Two delivery mechanisms

Webhooks: HTTP POST to any endpoint. HMAC-SHA256 signature in X-Cosmo-Signature-256. Versioned JSON payload with graph details and actor ID.
Slack: OAuth 2.0 authorization. Posts formatted messages directly to any channel. No middleware, no custom bots, no code to write.

How Cosmo Notifications works

01

Event captured immediately.

Detect

Cosmo monitors your federated graph for schema changes and other events. When any subgraph publishes an update that affects the federated schema, the event is captured immediately.

02

Sub-second delivery.

Dispatch

Notifications are dispatched to all configured channels in real-time. Webhook requests are sent with HMAC-SHA256 signatures. Slack messages are posted directly via the Slack API.

03

Per-channel event filtering.

Filter

Each notification channel has its own event subscription. Subscribe a channel to FEDERATED_GRAPH_SCHEMA_UPDATED and it receives only those events. Other channels can have different subscriptions.

04

Actor attribution in every payload.

Attribute

Payloads include the federated graph ID, name, namespace, and error status. An optional actor_id field identifies the person or system that triggered the event, supporting audit and compliance use cases.

What's included

Built into every Cosmo plan

Webhooks and Slack, both available on Free, Pro, and Enterprise.

Event-driven dispatch

Notifications go out the moment a schema event occurs. No polling interval, no scheduled check. Sub-second delivery to all configured channels.

HMAC-SHA256 verification

Every webhook request carries a signature in the X-Cosmo-Signature-256 header. Verify it in your endpoint to confirm the payload is authentic and untampered.

Per-channel event filtering

Each webhook and Slack integration subscribes to specific event types independently. Teams receive only the alerts relevant to them.

Actor attribution

Event payloads include an optional actor_id field identifying who triggered the change. Feeds audit logs and compliance reports without additional instrumentation.

Set up schema change notifications

Configure webhooks or Slack from the Cosmo Studio. Events start flowing the moment you save.

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Know when your federated graph changes, the moment it changes