Events
38 distinct extensions were invented to do this job. Each one is a provider deciding OpenAPI would not carry something and building their own way through. Where a job has many names and few uses each, nobody won — the problem was solved privately, over and over.
38 extensions
15965 occurrences
10 vendor-named
The extensions
| Extension | What it appears to do | Uses | Providers |
|---|---|---|---|
| x-stream-index | `x-stream-index` appears on schema objects and properties. Its value is a string. Used by a single provider across 4 OpenAPI documents. Observed values include `001`, `002`, `003`, `004`. Consistent w | 14091 | 1 |
| x-stream-event-doc-group | `x-stream-event-doc-group` appears on schema objects and properties. Its value is a string. Used by a single provider across 4 OpenAPI documents. Observed values include `other`, `call`, `transcriptio | 302 | 1 |
| x-stream-is-event | `x-stream-is-event` appears on schema objects and properties. Its value is a boolean flag. Used by a single provider across 4 OpenAPI documents. Consistent with events — this is inferred from where th | 302 | 1 |
| x-stream-ws-base-event-name | `x-stream-ws-base-event-name` appears on schema objects and properties. Its value is a string. Used by a single provider across 4 OpenAPI documents. Observed values include `VideoEvent`. Consistent wi | 302 | 1 |
| x-stream-event-client-type | `x-stream-event-client-type` appears on schema objects and properties. Its value is a boolean flag. Used by a single provider across 4 OpenAPI documents. Consistent with events — this is inferred from | 188 | 1 |
| x-stream-docs-page-id | `x-stream-docs-page-id` appears on schema objects and properties. Its value is a string. Used by a single provider across 3 OpenAPI documents. Observed values include `pinned_messages`, `threads`, `th | 158 | 1 |
| x-webhook-equivalent | `x-webhook-equivalent` appears on operations. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `webhook-timestamp`, `webhook-signature`. Consistent w | 132 | 1 |
| x-stream-event-call-type | `x-stream-event-call-type` appears on schema objects and properties. Its value is a boolean flag. Used by a single provider across 2 OpenAPI documents. Consistent with events — this is inferred from w | 114 | 1 |
| x-min-subscription | `x-min-subscription` appears on path items. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `standard`, `value`, `professional`, `free`. Consistent | 66 | 1 |
|
x-apideck-event-type
vendor |
`x-apideck-event-type` appears on operations. Its value is a string. Used by a single provider across 4 OpenAPI documents. It sits in the `x-apideck-` namespace, so its meaning is defined by apideck t | 56 | 1 |
| x-stream-filter-fields | `x-stream-filter-fields` appears on schema objects and properties. Its value is a structured object. Used by a single provider across 3 OpenAPI documents. Consistent with events — this is inferred fro | 37 | 1 |
| x-webhooks | `x-webhooks` appears at the root of the document. Its value is a structured object. Used by 15 providers across 35 OpenAPI documents. Consistent with events — this is inferred from where the key appea | 35 | 15 |
|
x-ibm-events
vendor |
`x-ibm-events` appears on operations. Its value is a structured object. Used by a single provider across 5 OpenAPI documents. It sits in the `x-ibm-` namespace, so its meaning is defined by ibm toolin | 29 | 1 |
| x-envoy-upstream-service-time | `x-envoy-upstream-service-time` appears on header objects. Its value is a string. Used by 2 providers across 10 OpenAPI documents. Observed values include `91`. Consistent with events — this is inferr | 26 | 2 |
| x-stream-map | `x-stream-map` appears on schema objects and properties. Its value is a structured object. Used by a single provider across 2 OpenAPI documents. Consistent with events — this is inferred from where th | 25 | 1 |
| x-event-type | `x-event-type` appears on operations. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `sync.complete`, `sync.paused`, `connection.created`, `connect | 18 | 1 |
| x-stream-sort-combinations | `x-stream-sort-combinations` appears on schema objects and properties. Its value is a list. Used by a single provider across 3 OpenAPI documents. Consistent with events — this is inferred from where t | 17 | 1 |
| x-stream-sort-fields | `x-stream-sort-fields` appears on schema objects and properties. Its value is a list. Used by a single provider across 3 OpenAPI documents. Consistent with events — this is inferred from where the key | 15 | 1 |
|
x-speakeasy-sse-sentinel
vendor |
`x-speakeasy-sse-sentinel` appears on response objects. Its value is a string. Used by a single provider across 1 OpenAPI document. It sits in the `x-speakeasy-` namespace, so its meaning is defined b | 10 | 1 |
| x-websocket | `x-websocket` appears on operations. Its value is a boolean flag. Used by a single provider across 1 OpenAPI document. Consistent with events — this is inferred from where the key appears and what it | 7 | 1 |
| x-downstream-splat-expressions | `x-downstream-splat-expressions` appears in the document. Its value is a list. Used by a single provider across 5 OpenAPI documents. Consistent with events — this is inferred from where the key appear | 5 | 1 |
| x-upstream-contract | `x-upstream-contract` appears in the info block. Its value is a string. Used by 4 providers across 5 OpenAPI documents. Observed values include `https://developer.wordpress.org/rest-api/`. Consistent | 5 | 4 |
|
x-ms-workflow-subscription-capacity
vendor |
`x-ms-workflow-subscription-capacity` appears on header objects. Its value is a string. Used by a single provider across 1 OpenAPI document. It sits in the `x-ms-` namespace, so its meaning is defined | 4 | 1 |
|
x-ms-workflow-subscription-id
vendor |
`x-ms-workflow-subscription-id` appears on header objects. Its value is a string. Used by a single provider across 1 OpenAPI document. It sits in the `x-ms-` namespace, so its meaning is defined by ms | 4 | 1 |
|
x-amz-meta-callback_domain
vendor |
`x-amz-meta-callback_domain` appears on schema objects and properties and on response objects. Its value is a string. Used by a single provider across 1 OpenAPI document. It sits in the `x-amz-` names | 2 | 1 |
|
x-amz-meta-callback_url
vendor |
`x-amz-meta-callback_url` appears on schema objects and properties and on response objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-amz | 2 | 1 |
|
x-ms-qps-subscribed
vendor |
`x-ms-qps-subscribed` appears on header objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-ms-` namespace, so its meaning is defined by m | 2 | 1 |
| x-callback-request | `x-callback-request` appears on operations. Its value is a boolean flag. Used by a single provider across 1 OpenAPI document. Consistent with events — this is inferred from where the key appears and w | 1 | 1 |
| x-error-events | `x-error-events` appears at the root of the document. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with events — this is inferred from where the ke | 1 | 1 |
| x-events | `x-events` appears on schema objects and properties. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with events — this is inferred from where the key | 1 | 1 |
|
x-goog-meta-callback
vendor |
`x-goog-meta-callback` appears on schema objects and properties. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-goog-` namespace, so its meani | 1 | 1 |
|
x-speakeasy-webhooks
vendor |
`x-speakeasy-webhooks` appears at the root of the document. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-speakeasy-` namespace, so its meani | 1 | 1 |
| x-subscriptions-contact | `x-subscriptions-contact` appears in the info block. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with events — this is inferred from where the key | 1 | 1 |
| x-upstream-documentation | `x-upstream-documentation` appears in the info block. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `https://developer.wordpress.org/rest-api/`. C | 1 | 1 |
| x-upstream-openapi | `x-upstream-openapi` appears in the info block. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `https://api.meetcampfire.com/api/schema?format=json | 1 | 1 |
| x-upstream-reference | `x-upstream-reference` appears in the info block. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `https://developer.wordpress.org/rest-api/`. Consi | 1 | 1 |
| x-upstream-spec | `x-upstream-spec` appears in the info block. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `https://github.com/inveniosoftware/invenio-openapi`. C | 1 | 1 |
| x-websocket-api | `x-websocket-api` appears at the root of the document. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with events — this is inferred from where the k | 1 | 1 |
Work with this as data
Every extension here is available over the APIs.io API and to AI agents over MCP. OpenAPI Extensions is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.
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Tools for openapi extensions
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apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=events&limit=10"
Everything under a tag
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