> ## Documentation Index > Fetch the complete documentation index at: https://synapse-docs.apart.io/llms.txt > Use this file to discover all available pages before exploring further. # Create Participant Session ## OpenAPI ````yaml /openapi.json post /v1/organizations/{organization_id}/apps/{app_id}/environments/{environment_id}/participant-sessions openapi: 3.1.0 info: description: Are we on the same page? title: Synapse version: 0.1.0 servers: [] security: [] paths: /v1/organizations/{organization_id}/apps/{app_id}/environments/{environment_id}/participant-sessions: post: tags: - v1-platform summary: Create Participant Session operationId: >- create_participant_session_v1_organizations__organization_id__apps__app_id__environments__environment_id__participant_sessions_post parameters: - in: path name: organization_id required: true schema: format: uuid title: Organization Id type: string - in: path name: app_id required: true schema: format: uuid title: App Id type: string - in: path name: environment_id required: true schema: format: uuid title: Environment Id type: string - in: header name: Idempotency-Key required: true schema: maxLength: 255 minLength: 1 title: Idempotency-Key type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/ParticipantSessionCreate' required: true responses: '201': content: application/json: schema: $ref: '#/components/schemas/ParticipantSessionCreated' description: Successful Response '401': content: application/json: schema: $ref: '#/components/schemas/ApiErrorResponse' description: Authentication required '403': content: application/json: schema: $ref: '#/components/schemas/ApiErrorResponse' description: Insufficient scope '404': content: application/json: schema: $ref: '#/components/schemas/ApiErrorResponse' description: Resource not found '409': content: application/json: schema: $ref: '#/components/schemas/ApiErrorResponse' description: State or idempotency conflict '422': content: application/json: schema: $ref: '#/components/schemas/ApiErrorResponse' description: Request validation failed '500': content: application/json: schema: $ref: '#/components/schemas/ApiErrorResponse' description: Internal server error security: - BearerAuth: [] - ApiKeyAuth: [] - SessionCookie: [] components: schemas: ParticipantSessionCreate: additionalProperties: false properties: evidence: additionalProperties: $ref: '#/components/schemas/ParticipantEvidenceInput' maxProperties: 500 title: Evidence type: object expires_in_seconds: default: 3600 maximum: 86400 minimum: 300 title: Expires In Seconds type: integer locale: default: en maxLength: 35 minLength: 2 pattern: ^[a-z]{2,3}(?:-[A-Z]{2})?$ title: Locale type: string program_id: format: uuid title: Program Id type: string signals: additionalProperties: type: number maxProperties: 100 title: Signals type: object subject_context: additionalProperties: true title: Subject Context type: object subject_id: format: uuid title: Subject Id type: string required: - program_id - subject_id title: ParticipantSessionCreate type: object ParticipantSessionCreated: properties: branding: $ref: '#/components/schemas/ExperienceBranding' consent: $ref: '#/components/schemas/ConsentRequirement' evaluation_id: format: uuid title: Evaluation Id type: string expires_at: format: date-time title: Expires At type: string hosted_url: anyOf: - type: string - type: 'null' title: Hosted Url participant_token: title: Participant Token type: string renderer_mode: enum: - hosted - embedded - hosted_or_embedded title: Renderer Mode type: string session_id: format: uuid title: Session Id type: string required: - session_id - evaluation_id - participant_token - expires_at - consent - renderer_mode - branding title: ParticipantSessionCreated type: object ApiErrorResponse: additionalProperties: false properties: detail: anyOf: - $ref: '#/components/schemas/ErrorDetail' - type: string - items: {} type: array - additionalProperties: true type: object title: Detail required: - detail title: ApiErrorResponse type: object ParticipantEvidenceInput: additionalProperties: false properties: answer: additionalProperties: true title: Answer type: object confirmations: default: 1 maximum: 100 minimum: 1 title: Confirmations type: integer source: default: api enum: - api - manual_entry title: Source type: string required: - answer title: ParticipantEvidenceInput type: object ExperienceBranding: additionalProperties: false description: Participant-safe branding pinned by an immutable experience version. properties: display_name: anyOf: - maxLength: 120 minLength: 1 type: string - type: 'null' title: Display Name primary_color: anyOf: - type: string - type: 'null' title: Primary Color title: ExperienceBranding type: object ConsentRequirement: properties: notice_text: maxLength: 4000 minLength: 1 title: Notice Text type: string notice_version: maxLength: 64 minLength: 1 pattern: ^[A-Za-z0-9](?:[A-Za-z0-9_.-]{0,62}[A-Za-z0-9])?$ title: Notice Version type: string purpose: maxLength: 64 minLength: 1 pattern: ^[A-Za-z0-9](?:[A-Za-z0-9_.-]{0,62}[A-Za-z0-9])?$ title: Purpose type: string required: - purpose - notice_version - notice_text title: ConsentRequirement type: object ErrorDetail: additionalProperties: false description: Stable structured detail returned by versioned API errors. properties: code: title: Code type: string context: anyOf: - additionalProperties: true type: object - type: 'null' title: Context message: title: Message type: string request_id: anyOf: - type: string - type: 'null' title: Request Id required: - code - message title: ErrorDetail type: object securitySchemes: BearerAuth: description: Named syn_ API key or migration-only legacy key. scheme: bearer type: http ApiKeyAuth: description: Header alias for a named or legacy API key. in: header name: X-API-Key type: apiKey SessionCookie: description: Opaque administrator browser session. in: cookie name: synapse_session type: apiKey ````