> ## Documentation Index > Fetch the complete documentation index at: https://docs.nohead.io/llms.txt > Use this file to discover all available pages before exploring further. # Get a revision ## OpenAPI ````yaml /openapi.json get /v1/records/{record_id}/revisions/{revision} openapi: 3.1.1 info: title: Nohead API version: 1.0.0 summary: Programmable content and data API. contact: name: Nohead email: hello@nohead.io url: https://nohead.io description: > The Nohead API manages projects, collections (your data models), their fields, and records (your content), with full version history. ## Authentication Send `Authorization: Bearer `. Servers, CI and agents use a project API key (`nohead_sk_...`, or `nohead_pk_...` for a published-only key; created in the web app under API keys) with scopes such as `records:read` or `schema:write`. Organization, project, member and API key management need a person signed in to the web app and are not available to API keys. ## Resources and IDs Every object has an `object` type, and every resource with an identity of its own an opaque, prefixed `id` (`col_`, `fld_`, `rec_`, ...). Record values live under `data`, keyed by each field's `key`. Timestamps are ISO 8601 in UTC. Deleting a record, collection, field, asset or webhook is soft: it can be restored until its `purge_after`. ## Lists Lists return `{ "data": [...], "meta": { "next_cursor", "has_more" } }`. Pass `limit` (1-100) and `cursor` to page, and `sort` (prefix `-` for descending). Records also take `filter[]=value`, `filter[published_at][exists]=true` and `expand=`. ## Errors Errors share one envelope: `{ "error": { "type", "message", "request_id", "details" } }`. `details` lists field-level problems as `{ "field", "code", "message" }`. Include the `request_id` when asking for support. ## Safe retries and concurrent edits Send `Idempotency-Key` on any `POST`, `PUT`, `PATCH` or `DELETE` to make retrying it safe: the first result is stored for 24 hours and returned again for the same request. Record responses carry the record's revision as an `ETag`; send it back as `If-Match` to update only if nobody changed the record in the meantime (`412` otherwise). ## History Every change to a record is a revision, attributed to the person or API key that made it: record revisions can be listed, diffed and reverted, and collections keep a schema history. Send `Nohead-Change-Note` to record why a change was made. Changes that rewrite existing values (such as a field's type) are explicit, previewable field migrations. How long revisions are kept depends on the organization's plan. Older ones are removed, but every record keeps its first revision and its last 10; `history_pruned_through` says how far history was removed. license: name: Proprietary identifier: LicenseRef-Proprietary servers: - url: https://api.nohead.io description: Production security: - apiKey: [] tags: - name: records x-group: Records description: Content entries, one at a time or many at once. - name: publishing x-group: Publishing description: Making records live, now or at a set time, and taking them down. - name: revisions x-group: Revisions description: A record's history, comparing two revisions, and going back to one. - name: drafts x-group: Drafts description: Changes to a record that wait to be merged into it, now or at a set time. - name: collections x-group: Collections description: User-defined data models. - name: schema-changes x-group: Schema changes description: A collection's schema history, and its schema at any version. - name: fields x-group: Fields description: Field definitions of a collection. - name: migrations x-group: Field migrations description: Explicit field changes that rewrite existing record values, with previews. - name: assets x-group: Assets description: Files stored for a project, uploaded directly to storage. - name: search x-group: Search description: Full-text search in collections and across a project. - name: webhooks x-group: Webhooks description: Event notifications sent to your URLs, and the secrets that sign them. - name: deliveries x-group: Webhook deliveries description: Each event sent to a webhook, its attempts, and retrying it. - name: audit x-group: Activity log description: The append-only trail of who changed what, through which client. - name: system x-group: System description: Service status, the caller, and its feature flags. paths: /v1/records/{record_id}/revisions/{revision}: parameters: - $ref: '#/components/parameters/RecordId' - $ref: '#/components/parameters/RevisionNumber' get: tags: - revisions summary: Get a revision operationId: record_revisions_get responses: '200': description: The revision with its snapshot and changes. content: application/json: schema: $ref: '#/components/schemas/RecordRevisionDetail' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' x-codeSamples: - lang: typescript label: TypeScript source: > import { Nohead } from "@nohead/sdk" const nohead = new Nohead() const result = await nohead.records.revisions.get("rec_01J9ZQ3F8X", 1) - lang: python label: Python source: | from nohead import Nohead nohead = Nohead() result = nohead.records.revisions.get("rec_01J9ZQ3F8X", 1) - lang: ruby label: Ruby source: | require "nohead" nohead = Nohead::Client.new result = nohead.records.revisions.get("rec_01J9ZQ3F8X", 1) components: parameters: RecordId: name: record_id in: path required: true schema: type: string example: rec_01J9ZQ3F8X5W2K7M4N6P0R1S2T RevisionNumber: name: revision in: path required: true description: Per-record revision number. schema: type: integer minimum: 1 schemas: RecordRevisionDetail: allOf: - $ref: '#/components/schemas/RecordRevisionProperties' - type: object required: - published_at - data - changes properties: published_at: $ref: '#/components/schemas/NullableTimestamp' data: $ref: '#/components/schemas/RecordData' changes: type: array items: $ref: '#/components/schemas/Change' unevaluatedProperties: false RecordRevisionProperties: type: object required: - id - object - record_id - revision - operation - actor - via - note - schema_version - reverted_to_revision - changed_fields - redacted_fields - draft - created_at properties: id: type: string examples: - rev_01J9ZQ3F8X5W2K7M4N6P0R1S2T object: const: record_revision record_id: type: string revision: type: integer operation: $ref: '#/components/schemas/RecordRevisionOperation' actor: $ref: '#/components/schemas/Actor' via: $ref: '#/components/schemas/Via' note: type: - string - 'null' schema_version: type: integer reverted_to_revision: type: - integer - 'null' changed_fields: type: array description: Keys of changed fields, and changed attributes. items: type: string redacted_fields: type: array description: | Keys of fields whose values in this revision were redacted (owners and admins redact them in the web app); those values read `{"$redacted": true}`. items: type: string draft: description: >- For a `merge`, the draft it merged, with who started and edited it; null otherwise. anyOf: - $ref: '#/components/schemas/MergedDraft' - type: 'null' created_at: $ref: '#/components/schemas/Timestamp' NullableTimestamp: type: - string - 'null' format: date-time RecordData: type: object description: > Field values keyed by field `key`. A rich text value is written as Markdown (GitHub Flavored, a string) or as a ProseMirror JSON document (`{"type": "doc", "content": [...]}`), and stored and read as the document (`rich_text` reads it as HTML or Markdown). Markdown is converted as closely as the vocabulary allows: headings below h3 become h3, task list items plain items, footnotes and raw HTML text. A document uses the web editor's vocabulary (Tiptap's StarterKit and tables) and nothing else; another name is refused with `invalid_format`, naming ours where one fits (`strong` is `bold`): - blocks: `paragraph`, `heading` (`level` 1-3), `blockquote`, `bulletList` and `orderedList` (`start`, `type`) of `listItem` (starting with a paragraph), `codeBlock` (`language`), `horizontalRule`, and `table` of `tableRow` of `tableHeader` or `tableCell` (`colspan`, `rowspan`, `colwidth`, `align`); any block may have `dir` (`auto`, `ltr`, `rtl`); - inline: `text` (non-empty) and `hardBreak`; - marks on text: `bold`, `italic`, `strike`, `underline`, `code` (alone), and `link` (`href`, and `target`, `rel`, `class`, `title`); a link's `href` is an `http`, `https`, `mailto`, `tel` or relative URL. An image of an asset is `{"type": "image", "attrs": {"asset_id": "ast_...", "alt": "..."}}` (in Markdown `![alt](ast_...)`, or the asset's `image_url`), between the document's blocks (not inside a list, quote or table), at most 100 per document (`too_many_images`); a newly shown image must be an uploaded JPEG, PNG, GIF, WebP, AVIF or SVG of the project (`invalid_reference`, `type_not_accepted`). `expand` embeds the assets, and published-only keys can read the images of published records. A record holds at most 2,000,000 bytes of values, all fields together (`too_large` on `data`); one already larger can still be edited without growing. additionalProperties: true examples: - title: Introducing Foo body: type: doc content: [] Change: type: object description: | One change between two states. Field changes carry `field` (current API key) and the stable `field_id`; attribute changes (`published_at`, `deleted_at`) carry `attribute`. additionalProperties: false required: - kind properties: field: type: - string - 'null' description: >- The field's key now, after any rename (its last key if it was deleted); null if the field no longer exists. field_id: type: string field_deleted: type: boolean description: Whether the field has been deleted since. attribute: type: string enum: - published_at - deleted_at kind: type: string enum: - added - changed - removed before: {} after: {} Error: type: object additionalProperties: false required: - error properties: error: type: object additionalProperties: false required: - type - message - request_id properties: type: $ref: '#/components/schemas/ErrorType' message: type: string request_id: $ref: '#/components/schemas/RequestId' details: type: array items: $ref: '#/components/schemas/ErrorDetail' RecordRevisionOperation: type: string description: What made the revision; `merge` is a draft's changes. enum: - create - update - publish - unpublish - delete - restore - revert - migrate - merge Actor: type: object additionalProperties: false required: - type - id - name properties: type: type: string enum: - user - api_key - system id: type: - string - 'null' description: >- The user (`usr_...`) or API key (`key_...`), or null for system changes. name: type: - string - 'null' description: | Resolved when read, never stored: a user's current name (or email), "Deleted user" once they deleted their account, an API key's name, or "System". Via: type: string description: The client a change came through; `scheduler` for scheduled changes. enum: - ui - api - cli - sdk - mcp - system - scheduler MergedDraft: type: object additionalProperties: false required: - id - created_at - created_by - edited_by description: The draft a `merge` revision merged, which is gone since. properties: id: type: string created_at: $ref: '#/components/schemas/Timestamp' created_by: $ref: '#/components/schemas/Actor' edited_by: type: array items: $ref: '#/components/schemas/Actor' Timestamp: type: string format: date-time description: ISO 8601 timestamp in UTC. examples: - '2026-09-27T12:00:00.000Z' RequestId: type: string pattern: ^req_[A-Za-z0-9]+$ examples: - req_01J9ZQ3F8X5W2K7M4N6P0R1S2T ErrorType: type: string enum: - invalid_request - authentication_error - plan_limit_exceeded - authorization_error - not_found - conflict - precondition_failed - validation_error - rate_limited - internal_error - service_unavailable ErrorDetail: type: object additionalProperties: false required: - code - message properties: field: type: string description: Key of the offending field or parameter, when applicable. code: type: string description: Machine-readable error code, e.g. `required`. message: type: string usage: type: integer description: Current usage, for `plan_limit` details. limit: type: integer description: The plan's limit, for `plan_limit` details. current_revision: type: integer description: The resource's current revision, for `revision_mismatch` details. record_id: type: string description: The record that already has the value, for `taken` details. draft_id: type: string description: The record's draft, for `draft_exists` and `draft_pending` details. responses: BadRequest: description: >- The request was malformed: unparseable JSON, an invalid query parameter, or a body key the operation doesn't take (detail code `unknown_parameter`, naming the key). headers: X-Request-Id: $ref: '#/components/headers/RequestId' content: application/json: schema: $ref: '#/components/schemas/Error' Unauthorized: description: Authentication is missing or invalid. headers: X-Request-Id: $ref: '#/components/headers/RequestId' content: application/json: schema: $ref: '#/components/schemas/Error' Forbidden: description: The caller is not allowed to perform this action. headers: X-Request-Id: $ref: '#/components/headers/RequestId' content: application/json: schema: $ref: '#/components/schemas/Error' NotFound: description: The resource does not exist or is not visible to the caller. headers: X-Request-Id: $ref: '#/components/headers/RequestId' content: application/json: schema: $ref: '#/components/schemas/Error' RateLimited: description: > Too many requests for this API key or user (or, with failing credentials, this IP address). A published-only key is counted per client IP. Wait `Retry-After` seconds; retries with the same `Idempotency-Key` are safe. On the Free plan, an organization's API keys are also refused once its API requests reach the month's limit, with a `plan_limit` detail (`field` `api_requests`, `usage` and `limit`), until the next month (UTC) or an upgrade. headers: X-Request-Id: $ref: '#/components/headers/RequestId' Retry-After: description: Seconds to wait before retrying. schema: type: integer RateLimit-Limit: $ref: '#/components/headers/RateLimitLimit' RateLimit-Remaining: $ref: '#/components/headers/RateLimitRemaining' RateLimit-Reset: $ref: '#/components/headers/RateLimitReset' content: application/json: schema: $ref: '#/components/schemas/Error' headers: RequestId: description: Unique identifier for the request, also echoed in error bodies. schema: $ref: '#/components/schemas/RequestId' RateLimitLimit: description: >- Requests allowed in the current window. Sent on every authenticated response. schema: type: integer RateLimitRemaining: description: Requests left in the current window. schema: type: integer RateLimitReset: description: Seconds until the window resets. schema: type: integer securitySchemes: apiKey: type: http scheme: bearer description: | Project-scoped API key, e.g. `nohead_sk_k7fz0a9c3m2q_`, or `nohead_pk_…` for a published-only key. Used by servers, CI, the CLI and coding agents. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.