> ## Documentation Index > Fetch the complete documentation index at: https://partner-help.letsdothis.com/llms.txt > Use this file to discover all available pages before exploring further. # Import an off-platform marketing opt-in > Import a single off-platform marketing opt-in — an email address collected by an external form tool such as a Webflow form — into the organiser's subscriber list, subscribed to marketing. A stable origin id makes retries leave the subscriber untouched, including when they unsubscribed after the first delivery. Throws if the import does not land, so a caller can retry. Use only for addresses whose owner explicitly opted in. ## OpenAPI ````yaml /openapi.json post /v0/opt-ins openapi: 3.1.0 info: title: Let's Do This API version: 0.1.0 description: > The full reference — getting started, pagination, error responses, rate limits and the changelog — lives at [partner-help.letsdothis.com/api-reference](https://partner-help.letsdothis.com/api-reference/overview). This page is the interactive OpenAPI view of the same specification. # Authentication Create an API key from **Settings** → **Credentials** in your Let's Do This account and send it as a bearer token: ```bash curl --request GET \ --url "https://api.letsdothis.com/v0/participants" \ --header "Authorization: Bearer YOUR-API-KEY" ``` Keep the key secret: it identifies your organization, so do not ship it in a website or native app. If a key is exposed, revoke it from the same section and create a replacement. # OpenAPI schema Download the [OpenAPI schema](https://api.letsdothis.com/documentation/json) to use with Postman or an OpenAPI client generator. servers: - url: https://api.letsdothis.com description: Production - url: https://api.staging.letsdothis.com description: Staging security: - bearerAuth: [] tags: - name: Events x-group: Events description: Events that participants can register for. - name: EventOccurrences x-group: Event occurrences description: >- Event occurrences scoped to the organizer associated with your Public API credentials. Unlike the public Events catalog, results are limited to your own events. - name: Races x-group: Races description: >- Races within an event occurrence. An event occurrence may have one or more races, for example a 5K and a 10K within the same race day. - name: Tickets x-group: Tickets description: Tickets that are available for events. - name: BookingForms x-group: Booking forms description: >- Booking forms define the questions a booker answers when registering for a ticket. A ticket usually references a single booking form, so expect zero or one, while a booking form may be shared across multiple tickets. - name: BookingFormFields x-group: Booking form fields description: >- Booking form fields are the individual questions on a booking form — their type, label, options, and whether an answer is required. A field can be reused across multiple forms. - name: Bookings x-group: Bookings description: >- Bookings are the transaction record for a registration. A booking may contain one or more participants (entries). - name: Participant x-group: Participants description: Participants are users who successfully booked an event. - name: LineItem x-group: Line items description: Financial details related to individual items within transactions. - name: AddOns x-group: Add-ons description: >- Organizer-owned products that can be purchased and allocated to participants. Imported products retain stable external identities. - name: DiscountCodes x-group: Discount codes description: >- Discount codes participants enter at checkout to reduce the price of a booking. - name: Credits x-group: Credits description: >- Credits are balances participants can spend at checkout, identified by their email address. - name: Referrals x-group: Referrals description: >- Referral programs, the referrers registered on them, and asynchronous imports of historical referrals. - name: Application x-group: Applications description: >- Applications are created when a user applies for tickets that are set up to require an application process, such as balloted or "Good For Age" entries. - name: Partner x-group: Partners description: >- Partners that were created by the organization who can have Reserved Entries assigned to them. - name: ReservedEntries x-group: Reserved entries description: >- Reserved Entries are entries that are reserved for a partner. After being assigned, the partner can then allocate these entries to participants. - name: Timing x-group: Timing description: >- Timing providers push bib numbers and bib-pack shipments back to Let's Do This for the startlist entries they received. Available to select timing partners only. - name: Identity x-group: API key description: >- What your API key can reach. Available to every key, including scoped ones. paths: /v0/opt-ins: post: tags: - Participant summary: Import an off-platform marketing opt-in description: >- Import a single off-platform marketing opt-in — an email address collected by an external form tool such as a Webflow form — into the organiser's subscriber list, subscribed to marketing. A stable origin id makes retries leave the subscriber untouched, including when they unsubscribed after the first delivery. Throws if the import does not land, so a caller can retry. Use only for addresses whose owner explicitly opted in. requestBody: required: true content: application/json: schema: type: object properties: emailAddress: type: string maxLength: 320 format: email pattern: >- ^(?!\.)(?!.*\.\.)([A-Za-z0-9_'+\-\.]*)[A-Za-z0-9_+-]@([A-Za-z0-9][A-Za-z0-9\-]*\.)+[A-Za-z]{2,}$ source: type: string minLength: 1 maxLength: 64 originId: type: string minLength: 1 maxLength: 255 required: - emailAddress - source - originId additionalProperties: false responses: '200': description: Import an off-platform marketing opt-in content: application/json: schema: description: Import an off-platform marketing opt-in type: object properties: emailAddress: description: The normalised address associated with the opt-in event type: string required: - emailAddress additionalProperties: false '400': description: The request was rejected content: application/json: schema: description: The request was rejected type: object properties: error: type: string enum: - validation_failed - invalid_request message: type: string issues: type: array items: type: object properties: path: type: string description: >- Dot-separated path to the rejected field in the schema being validated: the submitted payload before mapping, otherwise the action input. sourcePath: type: string description: >- Dot-separated path to the same field in the submitted payload. code: type: string message: type: string required: - path - code - message required: - error - message - issues '401': description: Unauthorized content: application/json: schema: description: Unauthorized type: object properties: statusCode: type: number enum: - 401 error: type: string message: type: string '403': description: Forbidden content: application/json: schema: description: Forbidden type: object properties: statusCode: type: number enum: - 403 error: type: string message: type: string '404': description: Not found content: application/json: schema: description: Not found type: object properties: statusCode: type: number enum: - 404 error: type: string message: type: string '409': description: Conflict content: application/json: schema: description: Conflict type: object properties: statusCode: type: number enum: - 409 error: type: string message: type: string '413': description: Payload too large content: application/json: schema: description: Payload too large type: object properties: statusCode: type: number enum: - 413 error: type: string message: type: string '415': description: Unsupported media type content: application/json: schema: description: Unsupported media type type: object properties: statusCode: type: number enum: - 415 error: type: string message: type: string '429': description: Rate limit exceeded headers: retry-after: schema: type: integer description: Seconds to wait before retrying the request. x-ratelimit-limit: schema: type: integer description: Requests permitted in the current window. x-ratelimit-remaining: schema: type: integer description: Requests still permitted in the current window. x-ratelimit-reset: schema: type: integer description: Seconds until the current window resets. content: application/json: schema: description: Rate limit exceeded type: object properties: statusCode: type: number enum: - 429 error: type: string message: type: string '500': description: Internal server error content: application/json: schema: description: Internal server error type: object properties: statusCode: type: number enum: - 500 error: type: string message: type: string components: securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT ````