> ## Documentation Index > Fetch the complete documentation index at: https://www.pickfu.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Add respondents > Adds more respondents to a completed survey by extending the sample size. The `respondentsAmount` parameter is the **new total** number of respondents (not the number to add). ### Prerequisites - Survey must be completed (`done` status) - MTurk-sourced surveys only - Under 1000 total respondents - Completed within the last 120 days - Account must have sufficient credits Use `preview: true` to get a cost estimate without making changes. Credits-only — card payment is not supported via the API. ## OpenAPI ````yaml /api-reference/openapi.json post /surveys/{id}/respondents openapi: 3.1.0 info: title: PickFu API version: 1.0.0 description: >- The PickFu API enables programmatic access to create surveys, retrieve results, and integrate PickFu into your workflows. ## Overview PickFu helps you get instant consumer feedback through surveys. With the API, you can: - Create surveys programmatically - Retrieve survey results and respondent data - Target specific audiences with demographic traits - Integrate PickFu into your product development workflow ## Rate Limits Selected endpoints (currently the CSV export endpoints) enforce per-caller rate limits and return `429 Too Many Requests` when exceeded. See each endpoint description for its specific budget. ## Authentication All API requests require a Bearer token — either an API key or an OAuth 2.0 access token. See the [Authentication guide](https://www.pickfu.com/docs/developers/authentication) for details. contact: name: PickFu Support email: support@pickfu.com url: https://www.pickfu.com servers: - url: https://api.pickfu.com/v1 description: Production - url: https://api.pickfu-sandbox.com/v1 description: Sandbox security: - bearerAuth: [] tags: - name: Surveys description: >- Create, retrieve, update, and publish surveys. Surveys are the core resource — each contains one or more questions with answer options. - name: Responses description: >- Retrieve individual responses (answers) for a survey, with pagination and per-question filtering. - name: Tags description: Organize surveys with tags. Tags are scoped to your team/account. - name: Projects description: >- Organize surveys into projects. Projects group related surveys and can be bookmarked or archived. - name: Traits description: >- Audience targeting and reporting traits used to reach specific demographics and segment survey results. - name: Playbooks description: >- Discover and retrieve step-by-step research playbooks. Each playbook is a structured sequence of polls designed for a specific research goal. - name: Help description: Search the PickFu help center for articles and guides. - name: Media description: >- Generate images from text prompts and upload media files to the PickFu CDN. paths: /surveys/{id}/respondents: post: tags: - Surveys summary: Add respondents description: >- Adds more respondents to a completed survey by extending the sample size. The `respondentsAmount` parameter is the **new total** number of respondents (not the number to add). ### Prerequisites - Survey must be completed (`done` status) - MTurk-sourced surveys only - Under 1000 total respondents - Completed within the last 120 days - Account must have sufficient credits Use `preview: true` to get a cost estimate without making changes. Credits-only — card payment is not supported via the API. operationId: addRespondents parameters: - schema: type: string in: path name: id required: true description: Survey ID (GUID) requestBody: required: true content: application/json: schema: type: object required: - respondentsAmount properties: respondentsAmount: type: integer minimum: 1 maximum: 1000 description: >- The new total number of respondents (not the delta). Must be greater than the current amount. preview: type: boolean default: false description: If true, returns cost estimate without making changes. additionalProperties: false responses: '200': description: Default Response content: application/json: schema: type: object properties: success: type: boolean preview: type: boolean data: type: object properties: currentRespondents: type: integer newRespondents: type: integer additionalRespondents: type: integer amount: type: number balance: type: number currency: type: string canPayWithBalance: type: boolean id: type: string respondentsAmount: type: integer state: type: string '400': description: Default Response content: application/json: schema: type: object properties: error: type: string message: type: string '401': description: Default Response content: application/json: schema: type: string '402': description: Default Response content: application/json: schema: type: object properties: error: type: string message: type: string amount: type: number balance: type: number currency: type: string '403': description: Default Response content: application/json: schema: type: object properties: error: type: string message: type: string '404': description: Default Response content: application/json: schema: type: string '409': description: Default Response content: application/json: schema: type: object properties: error: type: string message: type: string components: securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- OAuth2 access token obtained via the authorization flow. Include in the Authorization header as: `Bearer {access_token}` ````