> ## Documentation Index > Fetch the complete documentation index at: https://docs.evalezy.com/llms.txt > Use this file to discover all available pages before exploring further. # Create or update candidates > Creates or updates up to 2,000 candidates by your `external_id`. Returns `{"candidates": [{"id", "external_id", "created"}]}`. **Scope:** `evaluation:write` ## OpenAPI ````yaml /api-reference/openapi.json post /candidates openapi: 3.0.1 info: title: Evalezy AI Evaluation API version: v1 description: >- Create exams, register candidates, submit scanned answer copies or typed answers, and read question-wise AI marks with feedback. Results are drafts until you finalize them. Server-to-server only: never ship an API key inside a browser or mobile app. English answers only for now (Hindi and regional languages are on the roadmap). contact: name: Evalezy email: hello@evalezy.com url: https://evalezy.com servers: - url: https://api.evalezy.com/v1 description: Production security: - ApiKey: [] tags: - name: Exams description: Create, open, edit and look up exams. - name: Questions description: Add, edit and remove the questions of an exam. - name: Rubrics description: Marking criteria and model answers for long-answer questions. - name: Choice groups description: Internal choice ("attempt any N of M"). Beta, enabled on request. - name: Candidates description: >- Your students, keyed by your own external_id, and their exam registrations. - name: Uploads description: Presigned uploads for scanned answer copies (PDF). - name: Submissions description: Submit a copy or typed answers for a candidate and track its evaluation. - name: Results description: Question-wise marks, feedback and the checked (annotated) copy. - name: Review description: Teacher overrides, approval, finalize and unfinalize. - name: Credits description: Credit balance, rate card and price quotes. - name: Account description: Check which institute and scopes an API key has. paths: /candidates: post: tags: - Candidates summary: Create or update candidates description: >- Creates or updates up to 2,000 candidates by your `external_id`. Returns `{"candidates": [{"id", "external_id", "created"}]}`. **Scope:** `evaluation:write` operationId: upsertCandidates parameters: - name: Idempotency-Key in: header required: false schema: type: string maxLength: 255 example: exam-cbse-sci-10a-2026-10-14 description: >- Optional. Any unique string of 1-255 printable ASCII characters (a UUID works). Retrying with the same key within 48 hours replays the first response with `Idempotent-Replayed: true`. requestBody: content: application/json: schema: $ref: '#/components/schemas/CandidatesBody' example: candidates: - external_id: STU-10A-0142 name: Aarav Sharma roll_number: '14' section_or_class: 10-A - external_id: STU-10A-0143 name: Diya Patel roll_number: '15' section_or_class: 10-A required: true responses: '200': description: OK content: application/json: schema: type: object '401': $ref: '#/components/responses/Error401' '403': $ref: '#/components/responses/Error403' '422': $ref: '#/components/responses/Error422' '429': $ref: '#/components/responses/Error429' components: schemas: CandidatesBody: type: object properties: candidates: type: array items: $ref: '#/components/schemas/CandidateInput' candidate_ids: type: array items: type: string CandidateInput: type: object properties: external_id: type: string description: Your id for the candidate (required), up to 128 characters. name: type: string description: Up to 255 characters, no `<` or `>`. roll_number: type: string description: Up to 64 characters. section_or_class: type: string description: Up to 64 characters. metadata: $ref: '#/components/schemas/JsonNode' description: A JSON object of your own, up to 2 KB. Error: type: object description: >- Every error uses this envelope. Branch on `error.code`; the message is for humans. properties: error: type: object properties: code: type: string description: Stable machine code, e.g. `validation_failed`. example: validation_failed message: type: string description: Human-readable explanation. example: questions[1].max_marks must be a multiple of 0.5. request_id: type: string description: >- Quote this when you contact support (also sent as the X-Request-Id header). details: type: object description: >- Extra context. For `validation_failed`, `details.errors` lists every failing field. additionalProperties: true JsonNode: type: object responses: Error401: description: Missing or invalid API key. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: invalid_api_key message: The API key is not valid. request_id: req_4f9c2a7e1b3d4c8a9e6f0b2d5a7c1e3f Error403: description: >- The key lacks the required scope, or the API is not enabled for the institute. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: insufficient_scope message: This API key lacks the evaluation:write scope. request_id: req_4f9c2a7e1b3d4c8a9e6f0b2d5a7c1e3f details: required_scope: evaluation:write Error422: description: The request is valid JSON but breaks a rule. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: validation_failed message: questions[0].max_marks is required. request_id: req_4f9c2a7e1b3d4c8a9e6f0b2d5a7c1e3f details: errors: - field: questions[0].max_marks code: required message: max_marks is required. Error429: description: Rate limit or daily quota reached. Retry after the Retry-After header. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: rate_limited message: Too many requests. Retry after 2 s. request_id: req_4f9c2a7e1b3d4c8a9e6f0b2d5a7c1e3f securitySchemes: ApiKey: type: apiKey in: header name: X-API-Key description: >- Your institute's API key, `vak_eval_` followed by 48 hex characters. An institute admin creates keys in the dashboard under Settings -> Integrations -> API keys. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.