> ## Documentation Index > Fetch the complete documentation index at: https://ngrok.com/docs/llms.txt > Use this file to discover all available pages before exploring further. > Update an existing event subscription with new sources, destinations, or configuration. # Update ## OpenAPI ````yaml patch /event_subscriptions/{id} openapi: 3.0.0 info: title: ngrok OpenAPI version: 1.0.0 description: > The ngrok REST API at https://api.ngrok.com provides programmatic access to provision and configure every ngrok resource: endpoints, domains, API keys, IP policies, tunnels, certificates, and more. Full documentation: https://ngrok.com/docs/api **Authentication:** Send an API key as a bearer token: "Authorization: Bearer {API key}". Create and revoke keys at https://dashboard.ngrok.com/api-keys or via the /api_keys resource. Requests without credentials receive an error with code ERR_NGROK_200. **Versioning and deprecation policy:** Every request must include the "ngrok-version: 2" header; a missing header returns HTTP 400 with error code ERR_NGROK_218. Version 2 is the current version; all earlier versions are deprecated. ngrok never makes breaking changes to a published API version. Breaking changes ship only as a new version that clients explicitly opt in to via this header. Additive changes (new resources, methods, and fields, and bug fixes that match documented behavior) may ship to a live version. Full policy: https://ngrok.com/docs/api#versioning-and-api-stability **Rate limits:** By default, the API allows 120 requests per rolling 60-second window per account; some plans have higher limits. Exceeding the limit returns HTTP 429 with error code ERR_NGROK_226; wait for the window to pass before retrying. Details: https://ngrok.com/docs/errors/err_ngrok_226 **Errors:** Every 4xx and 5xx response carries the Error schema: the status_code, a human-readable msg, and in most cases a globally unique machine-readable error_code and a details object. Every error code is documented at https://ngrok.com/docs/errors servers: - url: https://api.ngrok.com security: - authentication: [] paths: /event_subscriptions/{id}: patch: tags: - EventSubscriptions summary: Update description: | Update an Event Subscription. operationId: EventSubscriptionsUpdate parameters: - $ref: '#/components/parameters/ngrokVersion' - name: id description: | Unique identifier for this Event Subscription. in: path required: true schema: type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/EventSubscriptionUpdate' responses: '200': description: | Update an Event Subscription. content: application/json: schema: $ref: '#/components/schemas/EventSubscription' 4XX: $ref: '#/components/responses/Error' 5XX: $ref: '#/components/responses/Error' components: parameters: ngrokVersion: name: ngrok-version in: header required: true schema: type: integer default: 2 schemas: EventSubscriptionUpdate: type: object properties: id: description: | Unique identifier for this Event Subscription. type: string metadata: description: > Arbitrary customer supplied information intended to be machine readable. Optional, max 4096 chars. type: string description: description: > Arbitrary customer supplied information intended to be human readable. Optional, max 255 chars. type: string sources: description: > Sources containing the types for which this event subscription will trigger type: array items: $ref: '#/components/schemas/EventSourceReplace' destination_ids: description: > A list of Event Destination IDs which should be used for this Event Subscription. type: array items: type: string EventSubscription: type: object properties: id: description: | Unique identifier for this Event Subscription. type: string uri: description: | URI of the Event Subscription API resource. type: string created_at: description: | When the Event Subscription was created (RFC 3339 format). type: string metadata: description: > Arbitrary customer supplied information intended to be machine readable. Optional, max 4096 chars. type: string description: description: > Arbitrary customer supplied information intended to be human readable. Optional, max 255 chars. type: string sources: description: > Sources containing the types for which this event subscription will trigger type: array items: $ref: '#/components/schemas/EventSource' destinations: description: | Destinations to which these events will be sent type: array items: $ref: '#/components/schemas/Ref' EventSourceReplace: type: object properties: type: description: | Type of event for which an event subscription will trigger type: string EventSource: type: object properties: type: description: | Type of event for which an event subscription will trigger type: string uri: description: | URI of the Event Source API resource. type: string Ref: type: object properties: id: description: | a resource identifier type: string uri: description: | a uri for locating a resource type: string Error: type: object description: > The error body every api.ngrok.com 4xx and 5xx response returns. Every error condition has a globally unique, documented error code; see https://ngrok.com/docs/errors required: - status_code - msg properties: error_code: description: > Globally unique machine-readable error code, for example ERR_NGROK_226. Each code is documented at https://ngrok.com/docs/errors/reference. Omitted on transport-level errors such as a plain 404 for an unknown path. type: string status_code: description: | The HTTP status code of the response, duplicated in the body. type: integer msg: description: | Human-readable description of the error and how to resolve it. type: string details: description: > Additional error context. details.operation_id identifies the failed request when contacting support. type: object additionalProperties: type: string responses: Error: description: > An error. The body carries a machine-readable error_code and a human-readable msg; every code is documented at https://ngrok.com/docs/errors. A 429 with error code ERR_NGROK_226 means the account exceeded the documented request-rate limit. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: authentication: type: http scheme: bearer ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.