Midpage Opinions API

openapi: 3.0.1
info:
  title: Midpage Legal Database Opinions API
  description: REST API for Midpage's US legal database ("Caselaw Building Blocks"). Search court opinions with semantic (vector), keyword (full-text), or hybrid search; retrieve full opinion data by ID, citation, or docket number with citator treatments; and read the authenticated user's identity and subscription status. Authenticate with a bearer token (API key) in the Authorization header.
  termsOfService: https://www.midpage.ai/
  contact:
    name: Midpage
    url: https://www.midpage.ai/
  version: '1.0'
servers:
- url: https://app.midpage.ai/api/v1
  description: Production server
security:
- apiKey: []
tags:
- name: Opinions
paths:
  /opinions/get:
    post:
      operationId: getOpinions
      tags:
      - Opinions
      summary: Get opinions
      description: 'Retrieve full opinion data by ID, citation, or docket number. Supports bulk reads of up to 100 items per request. Provide exactly one of `opinion_ids`, `citations`, or `docket` (not multiple).

        Lookup methods: `opinion_ids` (direct lookup, up to 100), `citations` (reporter citation, case-insensitive, up to 100), and `docket` (docket number + court; single lookup, may return multiple opinions).

        When using `citations` or `docket`, a lookup may match multiple opinions (e.g., majority and dissent from the same case). The response includes `citation_matches` or `docket_matches` arrays showing which lookups matched which opinion IDs.'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                opinion_ids:
                  type: array
                  items:
                    type: string
                  description: Array of opinion IDs to retrieve
                  example:
                  - '8623588'
                  - '1865773'
                citations:
                  type: array
                  items:
                    type: string
                  description: Array of citation strings to look up (case-insensitive)
                  example:
                  - 556 U.S. 662
                  - 550 U.S. 544
                docket:
                  $ref: '#/components/schemas/DocketLookup'
                include_content:
                  type: boolean
                  default: false
                  description: Include full HTML content
                include_detailed_treatments:
                  type: boolean
                  default: false
                  description: Include citator treatments
      responses:
        '200':
          description: Opinion data
          content:
            application/json:
              schema:
                type: object
                properties:
                  opinions:
                    type: array
                    items:
                      $ref: '#/components/schemas/OpinionFull'
                  citation_matches:
                    type: array
                    items:
                      $ref: '#/components/schemas/CitationMatch'
                    description: Only present when looking up by `citations`. Shows which citations matched which opinion IDs.
                  docket_matches:
                    type: array
                    items:
                      $ref: '#/components/schemas/DocketMatch'
                    description: Only present when looking up by `docket`. Shows which opinions matched.
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                    example: 'Must provide one of: opinion_ids, citations (as arrays), or docket (object with docket_number)'
components:
  schemas:
    DocketLookup:
      type: object
      description: Lookup by docket number and court. Requires docket_number and either court_id or court_abbreviation.
      required:
      - docket_number
      properties:
        docket_number:
          type: string
          description: The docket number (e.g., "19-1392", "1:23-cv-01234")
          example: 19-1392
        court_id:
          type: string
          description: Court identifier (e.g., "scotus", "ca9", "nysd")
          example: scotus
        court_abbreviation:
          type: string
          description: Court citation abbreviation (e.g., "SCOTUS", "9th Cir.", "S.D.N.Y.")
          example: SCOTUS
    DocketMatch:
      type: object
      description: Maps a docket lookup to the opinion(s) it matched
      properties:
        docket_number:
          type: string
          description: The docket number that matched
          example: 19-1392
        court_id:
          type: string
          description: Court identifier
          example: scotus
        court_abbreviation:
          type: string
          description: Court citation abbreviation
          example: SCOTUS
        opinion_id:
          type: string
          description: The matched opinion ID
          example: '145875'
    Citation:
      type: object
      properties:
        cited_as:
          type: string
          description: Full citation string
        volume:
          type: string
          description: Reporter volume
        reporter:
          type: string
          description: Reporter abbreviation
        page:
          type: string
          description: Starting page
    CitationMatch:
      type: object
      description: Maps a requested citation to the opinion(s) it matched
      properties:
        citation:
          type: string
          description: The citation string from the request
          example: 556 U.S. 662
        opinion_id:
          type: string
          description: The matched opinion ID
          example: '145875'
    OpinionFull:
      type: object
      properties:
        id:
          type: string
          description: Opinion identifier
        case_name:
          type: string
          description: Case name/caption
        court_id:
          type: string
          description: Court identifier
        court_abbreviation:
          type: string
          description: Citation abbreviation
        docket_number:
          type: string
          description: Court docket number
        date_filed:
          type: string
          format: date
          description: Filing date
        state:
          type: string
          nullable: true
          description: State name (null for federal courts)
        publish_status:
          type: string
          enum:
          - published
          - unpublished
          - unknown
          - in_chambers
          - separate
          - errata
          - relating_to
          description: Publication status for the opinion. Missing or uncertain metadata is returned as unknown.
        judge_name:
          type: string
          description: Authoring judge
        citations:
          type: array
          items:
            $ref: '#/components/schemas/Citation'
        citation_count:
          type: integer
          description: Number of times this opinion is cited by other opinions
        overall_treatment:
          type: string
          nullable: true
          enum:
          - Negative
          - Caution
          - Neutral
          description: 'Most negative treatment category from all citing opinions. Always returned. Priority: Negative > Caution > Neutral > null (no treatment data).'
        treatments:
          type: array
          items:
            $ref: '#/components/schemas/Treatment'
          description: Citator treatments (only included if include_detailed_treatments=true)
        html_content:
          type: string
          description: Full opinion text in HTML (only included if include_content=true)
    Treatment:
      type: object
      properties:
        citing_id:
          type: string
          description: ID of opinion citing this one
        treatment_category:
          type: string
          description: Treatment type
        treatment_description:
          type: string
          description: Detailed treatment
        is_authoritative:
          type: boolean
          description: Whether authoritative
        supporting_quote:
          type: string
          description: Quote supporting the treatment
  securitySchemes:
    apiKey:
      type: http
      scheme: bearer
      description: API key authentication. Get your API key from the Midpage Developer Portal at https://app.midpage.ai/developers