> ## Documentation Index > Fetch the complete documentation index at: https://developers.gonitro.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Create Participant(s) by Envelope ID > The **Create Participant(s) by Envelope ID** endpoint adds one or more participants to a specified envelope. Accepts either a single participant object or a bulk request with an 'items' array. Participants are associated to the parent Envelope and can sign multiple fields in different documents. When creating participants, the following limits apply: - Maximum participants: 200 ## OpenAPI ````yaml https://api.gonitro.dev/openapi.json post /sign/envelopes/{envelopeID}/participants openapi: 3.1.0 info: title: Nitro Sign Public API description: REST API for Nitro Sign version: '0.1' servers: - url: https://api.gonitro.dev security: - bearerAuth: [] paths: /sign/envelopes/{envelopeID}/participants: post: tags: - Sign summary: Create Participant(s) by Envelope ID description: > The **Create Participant(s) by Envelope ID** endpoint adds one or more participants to a specified envelope. Accepts either a single participant object or a bulk request with an 'items' array. Participants are associated to the parent Envelope and can sign multiple fields in different documents. When creating participants, the following limits apply: - Maximum participants: 200 operationId: createParticipant parameters: - name: envelopeID in: path description: >- A unique UUIDv4 string that identifies the envelope in the Nitro system. required: true schema: type: string format: uuid requestBody: description: Participant creation request - single or bulk content: application/json: schema: oneOf: - $ref: '#/components/schemas/SingleParticipantRequest' - $ref: '#/components/schemas/BulkParticipantRequest' examples: Single Participant: description: Create a single participant value: email: user@gonitro.com role: SIGNER authentication: type: AccessCode accessCode: '123456' Bulk Participants: description: Create multiple participants in a single request value: items: - email: user@gonitro.com role: SIGNER authentication: type: AccessCode accessCode: '123456' - email: user1@gonitro.com role: SIGNER authentication: type: SMS countryCode: '+1' phoneNumber: '1234567890' required: true responses: '200': description: >- Multiple participants created successfully. Returns an object with an 'items' array containing all created participants. content: application/json: schema: $ref: '#/components/schemas/BulkParticipantResponse' '201': description: Participant created successfully. content: application/json: schema: $ref: '#/components/schemas/Participant' '400': description: Invalid request content: application/problem+json: schema: $ref: '#/components/schemas/BadRequestProblemDetail' '401': description: Unauthorized - Invalid or missing JWT token content: application/problem+json: schema: $ref: '#/components/schemas/UnauthorizedProblemDetail' '404': description: Envelope not found content: application/problem+json: schema: $ref: '#/components/schemas/NotFoundProblemDetail' components: schemas: SingleParticipantRequest: description: Create a single participant properties: email: type: string description: The email address of the participant role: type: string description: > Role of the participant. - `signer`: A participant with the signer role can have fields assigned to them in order to sign the documents in the envelope. - `cc`: A participant with the cc role has read-only access. They can view the documents but cannot interact with them, so you cannot assign fields to a cc participant. enum: - signer - cc authentication: description: > Participant authentication When inviting a participant to a Nitro Sign flow, you must define how they will authenticate before signing the document. There are two supported methods: - Access code: A static code that you provide to the participant. - SMS code: A dynamic code that is sent to the participant's phone number. oneOf: - $ref: '#/components/schemas/AccessCode' - $ref: '#/components/schemas/SMS' title: Single Participant Request BulkParticipantRequest: description: Create multiple participants wrapped in an items array properties: items: type: array description: List of participants to create. items: $ref: '#/components/schemas/ParticipantCreate' title: Bulk Participant Request BulkParticipantResponse: type: object description: >- Response containing multiple created participants wrapped in an items array properties: items: type: array description: >- List of all participants created in this request. Each participant contains its unique ID and configuration. items: $ref: '#/components/schemas/Participant' description: >- List of all participants created in this request. Each participant contains its unique ID and configuration. title: Participants title: Participants required: - items title: Bulk Participant Response Participant: type: object properties: ID: type: string format: uuid description: The unique identifier of the participant email: type: string description: The email address of the participant role: type: string description: The role of the participant authentication: description: Participant authentication oneOf: - $ref: '#/components/schemas/AccessCode' - $ref: '#/components/schemas/SMS' BadRequestProblemDetail: type: object description: Bad Request error details example: type: https://developers.gonitro.com/docs/build-nitro/errors#400-bad-request title: Bad Request status: 400 detail: Request validation failed instance: /sign/envelopes validation_errors: name: must not be blank properties: type: type: string description: A URI reference that identifies the problem type title: type: string description: A short, human-readable summary of the problem type status: type: integer format: int32 description: The HTTP status code detail: type: string description: A human-readable explanation specific to this occurrence instance: type: string description: A URI reference that identifies the specific occurrence extensions: type: object additionalProperties: {} description: Additional problem-specific properties UnauthorizedProblemDetail: type: object description: Unauthorized error details example: type: >- https://developers.gonitro.com/docs/build-nitro/errors#401-unauthorized title: Unauthorized status: 401 detail: Missing or invalid Authorization header instance: /sign/envelopes properties: type: type: string description: A URI reference that identifies the problem type title: type: string description: A short, human-readable summary of the problem type status: type: integer format: int32 description: The HTTP status code detail: type: string description: A human-readable explanation specific to this occurrence instance: type: string description: A URI reference that identifies the specific occurrence extensions: type: object additionalProperties: {} description: Additional problem-specific properties NotFoundProblemDetail: type: object description: Not Found error details example: type: https://developers.gonitro.com/docs/build-nitro/errors#404-not-found title: Not Found status: 404 detail: Envelope with ID 'envelop-123' not found instance: /sign/envelopes/envelop-123 properties: type: type: string description: A URI reference that identifies the problem type title: type: string description: A short, human-readable summary of the problem type status: type: integer format: int32 description: The HTTP status code detail: type: string description: A human-readable explanation specific to this occurrence instance: type: string description: A URI reference that identifies the specific occurrence extensions: type: object additionalProperties: {} description: Additional problem-specific properties AccessCode: description: Access code properties: accessCode: type: string description: Access code. It must contain between 4-32 characters. type: type: string enum: - AccessCode title: type title: Access Code SMS: description: SMS properties: countryCode: type: string description: >- Country code. It must start with `+` and be followed by 1-4 digits. For example +1, +55, +598 phoneNumber: type: string description: >- Phone number. Enter digits only, without a country code or formatting characters. type: type: string enum: - SMS title: type title: SMS ParticipantCreate: type: object description: Request to create a new participant properties: email: type: string description: The email address of the participant role: type: string description: > Role of the participant. - `signer`: A participant with the signer role can have fields assigned to them in order to sign the documents in the envelope. - `cc`: A participant with the cc role has read-only access. They can view the documents but cannot interact with them, so you cannot assign fields to a cc participant. enum: - signer - cc authentication: description: > Participant authentication When inviting a participant to a Nitro Sign flow, you must define how they will authenticate before signing the document. There are two supported methods: - Access code: A static code that you provide to the participant. - SMS code: A dynamic code that is sent to the participant's phone number. oneOf: - $ref: '#/components/schemas/AccessCode' - $ref: '#/components/schemas/SMS' required: - role securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT ````