> ## Documentation Index
> Fetch the complete documentation index at: https://cactal.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Diff one source file

> Returns a bounded unified diff for one file name between two version refs, defaulting from published to head.



## OpenAPI

````yaml /api-reference/openapi.json get /websiteSourceCode/files/diff
openapi: 3.1.0
info:
  title: Cactal API
  version: 1.0.0
  description: >-
    The Cactal public API. Create, edit, publish, and operate websites
    programmatically. Authenticate every request with an API key sent as
    `Authorization: Bearer <key>`.
servers:
  - url: https://api.cactal.ai/v1
security:
  - apiKey: []
tags:
  - name: Documentation
    description: >-
      Search and read the Cactal product documentation for concepts, guides,
      agent workflows, platform behavior, and API operations.
  - name: Feedback
    description: >-
      Submit free-form product feedback from users and agents to the Cactal
      feedback inbox.
  - name: Websites
    description: >-
      Create and manage websites — the top-level resource that owns source code,
      content, assets, domains, and analytics.
  - name: Website editors
    description: >-
      Grant, list, and revoke website-scoped editor access, and invite
      collaborators to a single website by email.
  - name: API keys
    description: >-
      Create, scope, rotate, and revoke the API keys that authenticate
      programmatic and agent access.
  - name: Source code
    description: >-
      Read and edit the framework source files of a website draft. Mutations
      require an edit lease.
  - name: Publishing
    description: Validate, build, publish, and roll back website versions.
  - name: CMS collections
    description: >-
      Define the content model: collections of structured content owned by a
      website.
  - name: CMS fields
    description: Manage the typed fields that make up a collection schema.
  - name: CMS items
    description: >-
      Create, query, publish, and organize the content entries inside a
      collection.
  - name: Domains
    description: >-
      Manage platform subdomains and custom domains, including DNS verification
      and the primary domain.
  - name: Assets
    description: Upload and manage website files and images served from the Cactal CDN.
  - name: Media generation
    description: >-
      Generate reference-guided website images that are stored as ordinary
      Cactal CDN assets.
  - name: Project Context
    description: >-
      Upload private durable reference material that the website agent can
      search, read, and inspect.
  - name: Analytics
    description: >-
      Read first-party traffic analytics for a website and export datasets as
      CSV.
  - name: Organizations
    description: Manage organizations, members, and organization-wide invitations.
  - name: Audit log
    description: >-
      Read the immutable record of actions performed in an organization by users
      and API keys.
  - name: Billing
    description: >-
      Read billing state and manage plans, site capacity, and prepaid usage
      balance. Every billing operation requires the organization owner role,
      which API keys cannot hold — today these operations are performed from the
      dashboard, return 403 for API-key callers, and are hidden from MCP tool
      lists.
paths:
  /websiteSourceCode/files/diff:
    get:
      tags:
        - Source code
      summary: Diff one source file
      description: >-
        Returns a bounded unified diff for one file name between two version
        refs, defaulting from published to head.
      operationId: websiteSourceCode.files.diff
      parameters:
        - name: websiteId
          in: query
          required: true
          schema:
            type: string
            minLength: 1
        - name: from
          in: query
          required: false
          schema:
            description: >-
              Base side of the diff: a version number, `head`, or `published`.
              Defaults to `published`.
            type: string
            pattern: ^(head|published|[1-9][0-9]*)$
        - name: to
          in: query
          required: false
          schema:
            description: >-
              Target side of the diff: a version number, `head`, or `published`.
              Defaults to `head`.
            type: string
            pattern: ^(head|published|[1-9][0-9]*)$
        - name: name
          in: query
          required: true
          schema:
            type: string
            minLength: 1
            description: File name to compare.
      responses:
        '200':
          description: The selected file comparison and unified diff.
          content:
            application/json:
              schema:
                type: object
                properties:
                  websiteId:
                    type: string
                    description: Id of the website.
                  name:
                    type: string
                    description: Compared file name.
                  fromVersion:
                    type: integer
                    description: Resolved base version.
                  toVersion:
                    type: integer
                    description: Resolved target version.
                  fromType:
                    description: File type at the base version, when present.
                    type: string
                    enum:
                      - page
                      - component
                      - module
                      - global_css
                      - not_found
                      - website_config
                      - custom_head_start
                      - custom_head_end
                      - custom_body_start
                      - custom_body_end
                  toType:
                    description: File type at the target version, when present.
                    type: string
                    enum:
                      - page
                      - component
                      - module
                      - global_css
                      - not_found
                      - website_config
                      - custom_head_start
                      - custom_head_end
                      - custom_body_start
                      - custom_body_end
                  status:
                    type: string
                    enum:
                      - added
                      - removed
                      - modified
                      - unchanged
                    description: How the file differs between the two versions.
                  diff:
                    type: string
                    description: Unified diff hunks.
                  truncated:
                    description: >-
                      `true` when diff computation or output reached its bound.
                      Read both versions for the full content.
                    type: boolean
                required:
                  - websiteId
                  - name
                  - fromVersion
                  - toVersion
                  - status
                  - diff
                additionalProperties: false
        '400':
          description: >-
            Validation failed. The response `message` names the first invalid
            field.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceError'
        '401':
          description: Missing, invalid, expired, or revoked API key.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceError'
        '403':
          description: The authenticated principal lacks the required capability.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceError'
        '404':
          description: >-
            The resource does not exist or is outside the principal’s access
            scope.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceError'
        '429':
          description: >-
            Rate limit exceeded. Retry after the number of seconds in the
            `Retry-After` header.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceError'
components:
  schemas:
    ServiceError:
      type: object
      required:
        - kind
        - message
      description: >-
        Canonical error body returned by every non-2xx response. Extra fields
        carry error-specific details.
      properties:
        kind:
          type: string
          enum:
            - validation
            - unauthorized
            - forbidden
            - not_found
            - conflict
            - rate_limited
            - internal
          description: Stable, machine-readable error category.
        message:
          type: string
          description: Human-readable explanation of the failure.
        suggestion:
          type: string
          description: >-
            What to do next when the failure has a known fix; may name the exact
            operation to call.
        validValues:
          type: array
          items:
            type: string
          description: The acceptable values for the failing field, when the set is closed.
      additionalProperties: true
  securitySchemes:
    apiKey:
      type: http
      scheme: bearer
      description: >-
        Cactal API key. Create one in the dashboard or via `POST /apiKeys`. The
        plaintext key is shown once at creation.

````