> ## Documentation Index > Fetch the complete documentation index at: https://developers.perkstar.co.uk/llms.txt > Use this file to discover all available pages before exploring further. # List customers ## OpenAPI ````yaml /api/openapi.yaml get /customers openapi: 3.1.0 info: title: Perkstar Public REST API version: 2026-05-04.oauth description: | Programmatic access to your Perkstar loyalty data. Two authentication modes are supported: - **API key.** Per-org bearer token issued from Settings → API keys (`pk_live_…` / `pk_test_…`). Right choice for direct integrations, single-tenant POS adapters, and back-office sync. - **OAuth 2.0.** Three-legged authorization-code flow with PKCE, for marketplace listings (Square App Marketplace, Shopify App Store, Toast Partner Marketplace, Lightspeed). The merchant installs your app from the partner marketplace, lands on `/oauth/authorize`, approves the requested scopes, and your server exchanges the code at `/api/oauth/token` for a short-lived access token. See the dedicated OAuth section below. Every endpoint is scoped, rate-limited, and idempotent on POST. POS-adapter builders should start with the `/marketplace/*` endpoints — they collapse the typical "find-or-create customer + enrolment + post transaction" flow into a single round-trip with permanent dedupe via `external_transaction_id`. ## Test credentials Test credentials (`pk_test_…` or OAuth applications in TEST mode) can read API data, create isolated test transactions, and simulate wallet pushes. They cannot create, update, or delete live customers, enrolments, or webhook configuration. Test calls to `/marketplace/accrue` only work with an existing customer and enrolment; `/marketplace/enroll` is live-only. This prevents a sandbox integration from changing live customer records. Copy-paste cURL recipes are published at `/api/v1/curl-recipes.md` for teams that want to test the API before wiring the SDK. ## Response headers (universal) Every response, success or error, carries: - **X-Request-Id** — unique per request. Echo this in support tickets; we can find the exact call in the per-key audit log. - **X-API-Version** — date-versioned schema marker (`2026-05-04` as of writing). 12-month deprecation policy. - **X-RateLimit-Limit** — per-minute quota for the credential. - **X-RateLimit-Remaining** — tokens left in the current window. - **X-RateLimit-Reset** — unix-seconds when the window refills. - **Retry-After** — emitted on 429 only; seconds to wait. The reusable error responses below (`Unauthorized`, `Forbidden`, `NotFound`, `RateLimited`, `ValidationError`) declare these as strongly-typed `headers` so codegen against an error path has them. Success responses inline their `"200"` / `"201"` and rely on this convention rather than per-endpoint header declarations. contact: name: Perkstar url: https://perkstar.co.uk servers: - url: https://dashboard.perkstar.co.uk/api/v1 description: Production security: - bearerAuth: [] paths: /customers: get: tags: - Customers summary: List customers operationId: listCustomers parameters: - $ref: '#/components/parameters/Cursor' - $ref: '#/components/parameters/Limit' - in: query name: email description: Case-insensitive exact match. schema: type: string - in: query name: phone description: Exact-string match (no E.164 normaliser in-tree yet). schema: type: string - in: query name: externalRef description: | Match on the partner-supplied identifier you stored on create. Combine with `email` / `phone` for AND semantics. schema: type: string - in: query name: card_serial description: | Resolve the customer from either the stable POS barcode now displayed on the pass or a legacy wallet-pass serial. Returns an empty list if the identifier doesn't match an active pass in this organization. POS adapters scanning the customer's pass at the till use this to look up the customer record before posting a transaction. schema: type: string - in: query name: createdAfter schema: type: string format: date-time responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/CustomerList' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '429': $ref: '#/components/responses/RateLimited' security: - bearerAuth: [] components: parameters: Cursor: in: query name: cursor schema: type: string description: Opaque cursor returned in `next_cursor`. Limit: in: query name: limit schema: type: integer default: 50 minimum: 1 maximum: 200 schemas: CustomerList: allOf: - $ref: '#/components/schemas/Pagination' - type: object properties: data: type: array items: $ref: '#/components/schemas/Customer' Pagination: type: object required: - data - has_more - next_cursor - limit properties: has_more: type: boolean next_cursor: type: string nullable: true limit: type: integer Customer: type: object properties: id: type: string customer_number: type: integer email: type: string nullable: true phone: type: string nullable: true first_name: type: string nullable: true last_name: type: string nullable: true date_of_birth: type: string nullable: true format: date-time consent_marketing: type: boolean consent_ad_tracking: type: boolean external_ref: type: string nullable: true description: | Partner-supplied identifier (Shopify customer GID, Toast guest UUID, Square customer id, …). Unique per org. POST `/customers` upserts on this when supplied. anonymized_at: type: string nullable: true format: date-time deleted_at: type: string nullable: true format: date-time created_at: type: string format: date-time updated_at: type: string format: date-time Error: type: object properties: error: type: object required: - type - message - code properties: type: type: string enum: - authentication_error - permission_error - rate_limit_error - validation_error - not_found - idempotency_error - server_error message: type: string code: type: string param: type: string responses: Unauthorized: description: Missing / invalid / expired API key headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-API-Version: $ref: '#/components/headers/XAPIVersion' X-RateLimit-Limit: $ref: '#/components/headers/XRateLimitLimit' X-RateLimit-Remaining: $ref: '#/components/headers/XRateLimitRemaining' X-RateLimit-Reset: $ref: '#/components/headers/XRateLimitReset' content: application/json: schema: $ref: '#/components/schemas/Error' Forbidden: description: API key is missing the required scope headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-API-Version: $ref: '#/components/headers/XAPIVersion' X-RateLimit-Limit: $ref: '#/components/headers/XRateLimitLimit' X-RateLimit-Remaining: $ref: '#/components/headers/XRateLimitRemaining' X-RateLimit-Reset: $ref: '#/components/headers/XRateLimitReset' content: application/json: schema: $ref: '#/components/schemas/Error' RateLimited: description: Per-key rate limit exceeded headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-API-Version: $ref: '#/components/headers/XAPIVersion' X-RateLimit-Limit: $ref: '#/components/headers/XRateLimitLimit' X-RateLimit-Remaining: $ref: '#/components/headers/XRateLimitRemaining' X-RateLimit-Reset: $ref: '#/components/headers/XRateLimitReset' Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/Error' headers: XRequestId: description: | Unique id for this request. Echo this in your support tickets and we can trace the exact call in the audit log on the API key detail page. schema: type: string XAPIVersion: description: | Date-versioned schema marker. The current value is `2026-05-04`. Bumps follow the 12-month deprecation policy documented in the in-dashboard docs page. schema: type: string XRateLimitLimit: description: Total requests permitted per minute for this credential. schema: type: integer XRateLimitRemaining: description: Requests left in the current 60s window. schema: type: integer XRateLimitReset: description: Unix-seconds timestamp when the current window refills. schema: type: integer RetryAfter: description: | Seconds to wait before retrying. Only emitted on 429 responses. schema: type: integer securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: pk_live_… / pk_test_… or perk_at_… ```` ## Related topics - [Authentication and scopes](/fundamentals/authentication.md) - [List transactions](/api-reference/transactions/list-transactions.md) - [List enrollments](/api-reference/enrollments/list-enrollments.md) - [Test mode](/fundamentals/test-mode.md) - [Get a customer](/api-reference/customers/get-a-customer.md)