> ## Documentation Index > Fetch the complete documentation index at: https://docs.conversion.ai/llms.txt > Use this file to discover all available pages before exploring further. # List Fields > List field schemas (key, label, object type, and value data type). Use this endpoint to discover which field keys are available for use in the `fields` and `companyFields` maps of other endpoints. Omit `objectType` to return fields across all object types. Results are paginated with an opaque cursor returned as `pagination.nextCursor`. Pass it back as the `cursor` query parameter to fetch the next page. A `null` cursor means there are no more results. ## OpenAPI ````yaml /openapi.json get /v2/fields openapi: 3.1.0 info: title: Conversion API version: 2.0.0 description: >- The Conversion API lets you programmatically manage contacts, track custom events, and manage their associated data. servers: - url: https://pub-api.conversion.ai/api security: - apiKey: [] paths: /v2/fields: get: summary: List Fields description: >- List field schemas (key, label, object type, and value data type). Use this endpoint to discover which field keys are available for use in the `fields` and `companyFields` maps of other endpoints. Omit `objectType` to return fields across all object types. Results are paginated with an opaque cursor returned as `pagination.nextCursor`. Pass it back as the `cursor` query parameter to fetch the next page. A `null` cursor means there are no more results. operationId: listFields parameters: - name: objectType in: query required: false schema: type: string enum: - CONTACT - COMPANY - OPPORTUNITY - CAMPAIGN_MEMBER description: >- Filter results to a single object type (case-insensitive). Omit to return fields across all object types. An unsupported value returns an `invalid_object_type` error. examples: contact: value: CONTACT - name: limit in: query required: false schema: type: integer minimum: 1 maximum: 100 default: 50 description: >- The maximum number of fields to return per page. Defaults to 50. Values are clamped to the range [1, 100] rather than rejected; values above 100 return 100 results. - name: cursor in: query required: false schema: type: string description: >- The opaque pagination cursor returned as `pagination.nextCursor` by a previous call. Omit to fetch the first page. An invalid or malformed cursor returns an `invalid_cursor` error. examples: next-page: value: eyJjcmVhdGVkQXQiOiIyMDI2LTAxLTE1VDEwOjMwOjAwWiJ9 responses: '200': description: Field schemas retrieved successfully. content: application/json: schema: type: object properties: data: type: object required: - fields properties: fields: type: array description: The current page of field schemas. items: type: object required: - key - label - objectType - dataType properties: key: type: string description: >- The field key used in the `fields` and `companyFields` maps of other endpoints. examples: - first_name label: type: string description: The human-readable display name of the field. examples: - First Name objectType: type: string enum: - CONTACT - COMPANY - OPPORTUNITY - CAMPAIGN_MEMBER description: >- The object this field belongs to. Always present, even when filtering by a single object type. dataType: type: string enum: - STRING - NUMBER - BOOLEAN - DATE - DATETIME description: The data type of the field's value. pagination: type: object required: - nextCursor properties: nextCursor: type: - string - 'null' description: >- Opaque cursor for the next page, or `null` when there are no more results. This is the single source of truth for whether more results exist. examples: with-more-pages: summary: More pages available value: data: fields: - key: first_name label: First Name objectType: CONTACT dataType: STRING - key: annual_revenue label: Annual Revenue objectType: COMPANY dataType: NUMBER pagination: nextCursor: eyJjcmVhdGVkQXQiOiIyMDI2LTAxLTE1VDEwOjMwOjAwWiJ9 last-page: summary: Last page value: data: fields: - key: signup_date label: Signup Date objectType: CONTACT dataType: DATETIME pagination: nextCursor: null '400': description: The request was malformed or contained invalid data. content: application/json: schema: $ref: '#/components/schemas/Error' examples: invalid-object-type: summary: Unsupported object type value: error: code: invalid_object_type message: >- unsupported object type 'DEAL'; supported values: [CONTACT COMPANY OPPORTUNITY CAMPAIGN_MEMBER] invalid-cursor: summary: Invalid cursor value: error: code: invalid_cursor message: invalid pagination cursor '401': description: Authentication failed. content: application/json: schema: $ref: '#/components/schemas/Error' examples: unauthorized: summary: Missing or invalid API key value: error: code: unauthorized message: API key is required '500': description: An unexpected server error occurred. content: application/json: schema: $ref: '#/components/schemas/Error' examples: internal: summary: Internal error value: error: code: internal_error message: failed to load field schemas components: schemas: Error: type: object properties: error: type: object required: - code - message properties: code: type: string description: A machine-readable error code. examples: - invalid_email message: type: string description: A human-readable error description. examples: - 'invalid email format: not-an-email' securitySchemes: apiKey: type: apiKey in: header name: X-API-Key description: >- Your Conversion API key. Found in **Settings > Integrations** in the dashboard. Format: `sk_live__`. ````