> ## Documentation Index > Fetch the complete documentation index at: https://docs.globalstack.io/llms.txt > Use this file to discover all available pages before exploring further. # Start verification for a customer > Creates a hosted verification session for a customer scoped to the calling integration. The returned `hosted_url` is the hosted verification link that the merchant must surface to their customer to complete verification. ### Path - `customer_id` — required. The `cust_…` external id of an existing, non-default customer that belongs to the calling integration. ### Body - `tier` — optional. One of `tier_1`, `tier_2`. Defaults to the next tier above the customer's current tier (`tier_0` → `tier_1`; `tier_1` → `tier_2`). `tier_0` is never a valid requested tier. - `redirect_url` — optional. HTTPS URL the merchant wants the customer redirected to after the verification flow completes. Stored verbatim and echoed back on the response. ### Replay & link refresh If a `pending` session already exists for the same `(customer_id, tier_requested)` and its `hosted_url_expires_at` is in the future, this endpoint returns that existing session unchanged — no second upstream call. Clients can safely retry POSTs without an Idempotency-Key header. If that `pending` session exists but its `hosted_url` has **expired**, this endpoint mints a fresh hosted link and refreshes the same session in place, returning it with a new `hosted_url` / `hosted_url_expires_at`. Call this endpoint again to regenerate an expired verification link. ### Example ``` POST /v1/customers/cust_01HXYZ/verifications { "tier": "tier_1", "redirect_url": "https://merchant.com/onboarding/complete" } ``` ## OpenAPI ````yaml /api-reference/openapi.json post /v1/customers/{customerId}/verifications openapi: 3.0.0 info: title: GlobalStack API version: 1.0.0 description: > # Introduction GlobalStack API for cross-border payments powered by stablecoin rails. Getting started: authenticate with a Bearer token, make your first call to `GET /v1/currencies`, and explore. **Key operations:** - **Onramp** — convert external fiat into crypto credited to a wallet. - **Offramp** — convert crypto from a wallet into fiat delivered to a beneficiary. - **Conversion** — move value between two wallets belonging to the same customer. - **Transfer** — send crypto from a wallet to an external address. - **Deposit** — receive external crypto into a wallet via a deposit address. See the sections below for authentication, response shape, idempotency, references, metadata, and webhooks. ## Authentication All API requests require a Bearer token in the `Authorization` header: ``` Authorization: Bearer gsa_sk_live_your_api_key ``` API keys use the `gsa_sk_live_` prefix. API keys are scoped to a single merchant account. All resources created with a key belong to that merchant. Keep your keys secret — do not expose them in client-side code or public repositories. To rotate a key, generate a new one from your dashboard and update your integration before revoking the old key. ## API Response Shape Every response — success or failure — follows the same envelope: ```json { "status": true, "message": "Onramp created successfully", "code": "ok", "data": { }, "meta": { "request_id": "req_01ABC...", "timestamp": "2026-04-22T02:00:00Z", "version": "1" } } ``` **Fields:** - `status` (boolean) — whether the HTTP call succeeded. This is not the business status of the underlying resource. - `message` (string) — human-readable explanation for developers and logs. Do not show to end users. - `code` (string) — stable machine-readable result. `ok` on success, or an error code like `bad_request`. - `data` — the resource payload on success (object, array, or scalar). `null` on failure. - `meta` — request-scoped metadata, always present. Includes `request_id` (quote this in support tickets), `timestamp`, and `version`. On list endpoints, also includes `page`, `per_page`, `total`, `has_more`. On validation errors, includes `errors` array and `next_steps`. Error responses include `next_steps` in `meta` with an `action` string and a `docs_url` link: ```json { "status": false, "message": "Your request has validation errors.", "code": "bad_request", "data": null, "meta": { "request_id": "req_01ABC...", "timestamp": "2026-04-22T02:00:00Z", "version": "1", "errors": [ { "field": "amount", "code": "required", "message": "Amount is required." } ], "next_steps": { "action": "Review the request and retry with corrected parameters.", "docs_url": "https://docs.globalstack.io/errors#bad_request" } } } ``` ## Idempotency Pass an `Idempotency-Key` header on any create endpoint to make the request safely retryable: ``` Idempotency-Key: your-unique-key-here ``` **Rules:** - Same key + same body = returns the original response (no side effects). - Same key + different body = returns `idempotency_conflict` (409). - Keys are scoped to your merchant account. - Keys expire after 24 hours. Use idempotency keys for any operation that creates a resource or moves money. This protects against network retries, duplicate webhooks, and client-side retry loops. ## Rate Limits Requests over the rate limit are rejected with HTTP `429` and the error code `rate_limited`: ```json { "status": false, "message": "Too many requests. Slow down and retry shortly.", "code": "rate_limited" } ``` **Money-movement writes** (creating transfers, offramps, conversions, or wallet operations) are limited **per merchant account** — the budget is shared across all of your API keys and dashboard sessions. Reads are not limited. On a `429`, back off and retry with jitter; for money movement, reuse the same `Idempotency-Key` so the retry stays safe. ## Reference Every money movement operation (onramp, offramp, conversion, transfer) accepts an optional `reference` field — a merchant-supplied identifier that is unique per merchant account. ```json { "reference": "INV-2026-001", "wallet_id": "wal_..." } ``` If you omit `reference`, the API generates one automatically (prefixed `ref_`). References are unique per merchant — attempting to create two operations with the same reference returns the existing operation (same behavior as idempotency, but permanent and not time-limited). Use `reference` to correlate GlobalStack operations with your own system records (invoices, orders, payouts). ## Metadata Most create endpoints accept an optional `metadata` object — a flat set of string key/value pairs stored on the resource: ```json { "metadata": { "order_id": "ord_12345", "customer_email": "alice@example.com" } } ``` Metadata is returned on every GET response and in webhook payloads. It is not used by GlobalStack for processing — it exists for your own record-keeping. Resources that accept metadata: customers, wallets, senders, beneficiaries, wallet credentials, deposit addresses, onramps, offramps, conversions, and transfers. ## Webhook Signatures Every webhook delivery is signed so you can verify it came from GlobalStack and was not tampered with in transit. Signatures follow the [Svix](https://docs.svix.com/receiving/verifying-payloads/how) standard, so you can verify them with any Svix library — or manually with the construction below. Each delivery carries three headers: ``` svix-id: msg_2gT8sV... # unique message id (the body's event_id, prefixed msg_) svix-timestamp: 1718960400 # unix seconds when the delivery was signed svix-signature: v1,g0hM9SsE... # space-separated list of v1, ``` Your signing secret (prefixed `whsec_`) is returned in plaintext **exactly once** — when you create a webhook endpoint or rotate its secret. Store it securely; you cannot retrieve it again. **Verify with a Svix library (recommended):** ```python from svix.webhooks import Webhook wh = Webhook(signing_secret) # the whsec_... value payload = wh.verify(raw_request_body, request_headers) # raises on a bad signature ``` **Verify manually:** 1. Build the signed content by joining the id, timestamp, and the **raw** request body with dots: ``` signed_content = svix_id + "." + svix_timestamp + "." + raw_body ``` 2. Take your signing secret, drop the `whsec_` prefix, and base64-decode the remainder — those bytes are your HMAC key. 3. Compute `base64(HMAC-SHA256(key, signed_content))`. 4. The `svix-signature` header is a space-separated list of `v1,` entries (an endpoint can have more than one valid secret during a rotation). Compare your computed value against each entry's signature — the part after `v1,` — using a constant-time comparison, and accept if any matches. 5. Reject deliveries whose `svix-timestamp` differs from your current time by more than a few minutes, to guard against replay. The body's `event_id` equals the `svix-id` without its `msg_` prefix, so you can use either to deduplicate redelivered events. ## Request IDs Every response carries an `X-Request-Id` header (also surfaced in `meta.request_id`). Include the value when reporting issues — it scopes backend logs to your specific request. You may also send your own `X-Request-Id` header. Values matching `^[A-Za-z0-9_-]{1,128}$` are honored verbatim; anything else is replaced with a generated id. ## Versioning Public endpoints are versioned under `/v1/`. Breaking changes ship under a new major version; additive changes (new fields, new endpoints) ship under the existing version. contact: name: Paystack Cross-Border url: https://globalstack.io servers: - url: https://api.globalstack.io description: Production security: - BearerAuth: [] tags: - name: Supported Countries - name: Supported Currencies - name: Customers - name: Wallets - name: Beneficiaries - name: Quotes - name: Onramps - name: Offramps - name: Conversions - name: Transfers - name: Transactions - name: Notification Webhooks - name: Me paths: /v1/customers/{customerId}/verifications: post: tags: - Customers summary: Start verification for a customer description: > Creates a hosted verification session for a customer scoped to the calling integration. The returned `hosted_url` is the hosted verification link that the merchant must surface to their customer to complete verification. ### Path - `customer_id` — required. The `cust_…` external id of an existing, non-default customer that belongs to the calling integration. ### Body - `tier` — optional. One of `tier_1`, `tier_2`. Defaults to the next tier above the customer's current tier (`tier_0` → `tier_1`; `tier_1` → `tier_2`). `tier_0` is never a valid requested tier. - `redirect_url` — optional. HTTPS URL the merchant wants the customer redirected to after the verification flow completes. Stored verbatim and echoed back on the response. ### Replay & link refresh If a `pending` session already exists for the same `(customer_id, tier_requested)` and its `hosted_url_expires_at` is in the future, this endpoint returns that existing session unchanged — no second upstream call. Clients can safely retry POSTs without an Idempotency-Key header. If that `pending` session exists but its `hosted_url` has **expired**, this endpoint mints a fresh hosted link and refreshes the same session in place, returning it with a new `hosted_url` / `hosted_url_expires_at`. Call this endpoint again to regenerate an expired verification link. ### Example ``` POST /v1/customers/cust_01HXYZ/verifications { "tier": "tier_1", "redirect_url": "https://merchant.com/onboarding/complete" } ``` operationId: CustomerController.createVerification parameters: - in: header name: Idempotency-Key required: false schema: type: string pattern: ^[A-Za-z0-9_\-]{8,255}$ description: >- Optional client-supplied key. Identical key + identical body within 24h replays the original response. Identical key + different body returns 409 idempotency_conflict. The hash is over raw bytes — clients retrying must send the byte-identical body; a re-serialised JSON payload will produce a different hash and a 409. Strongly recommended for retry-safe clients. requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateVerifyDto' description: CreateVerifyDto required: false responses: '200': content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiSuccessEnvelope' - type: object required: - data - meta properties: message: type: string example: Verification session created data: $ref: '#/components/schemas/KycSessionResponse' meta: $ref: '#/components/schemas/ApiResponseMetaSchema' description: Verification session created '400': description: >- customer_id malformed, tier / redirect_url failed validation, or the customer is already at the highest tier content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiErrorEnvelope' - type: object properties: code: type: string enum: - invalid_input '401': description: Unauthorized — invalid or missing API key content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiErrorEnvelope' - type: object properties: code: type: string enum: - authentication_failed '404': description: Customer not found in this integration content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiErrorEnvelope' - type: object properties: code: type: string enum: - not_found '409': description: >- Conflict — possible codes: `idempotency_conflict` (Idempotency-Key reused with a different request body), `idempotency_in_progress` (a request with the same Idempotency-Key is still in flight). content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiErrorEnvelope' - type: object properties: code: type: string enum: - idempotency_conflict - idempotency_in_progress '500': description: KYC provider upstream is unreachable content: application/json: schema: allOf: - $ref: '#/components/schemas/ApiErrorEnvelope' - type: object properties: code: type: string enum: - external_service_unavailable components: schemas: CreateVerifyDto: properties: tier: type: string enum: - tier_0 - tier_1 - tier_2 redirect_url: maxLength: 2048 type: string format: url type: object ApiSuccessEnvelope: properties: status: type: boolean enum: - true example: true message: type: string description: Human-readable summary example: Resource fetched successfully code: type: string enum: - ok example: ok type: object required: - status - message - code KycSessionResponse: properties: id: type: string description: KYC session id (prefixed kyc_). example: kyc_01HXYZABC1234567890ABCDEFG customer_id: type: string description: Owning customer id (prefixed cust_). example: cust_01HXYZABC1234567890ABCDEFG status: enum: - not_started - in_progress - pending - completed - failed type: string description: Current session status example: pending tier_requested: enum: - tier_1 - tier_2 - tier_2 type: string description: Tier the merchant requested for this customer example: tier_1 tier_current: enum: - tier_0 - tier_1 - tier_2 type: string description: Customer's current tier at the time of this response. example: tier_0 hosted_url: type: string description: >- Hosted WebSDK URL the customer must open to complete verification. Omitted for reliance-approved sessions (provider=merchant_reliance) — those complete without a hosted link. example: http://localhost:3000/_mock/verify/kyc_01HXYZABC1234567890ABCDEFG hosted_url_expires_at: type: string format: date-time example: '2026-04-22T03:00:00.000Z' created_at: type: string format: date-time example: '2026-04-22T02:00:00.000Z' updated_at: type: string format: date-time example: '2026-04-22T02:00:00.000Z' type: object required: - id - customer_id - status - tier_requested - tier_current - created_at - updated_at ApiResponseMetaSchema: properties: request_id: type: string description: ULID-prefixed identifier for this request example: req_01HXYZ4K5ABCDEFGHJKLMNPQRS timestamp: type: string format: date-time example: '2026-05-14T15:43:55.732Z' version: type: string description: Major API version parsed from /vN/ example: '1' type: object required: - request_id - timestamp - version ApiErrorEnvelope: properties: status: type: boolean enum: - false example: false message: type: string description: Human-readable failure summary example: Resource not found code: type: string description: Stable error code for branching logic example: not_found data: type: object nullable: true example: null meta: $ref: '#/components/schemas/ApiErrorMetaSchema' type: object required: - status - message - code - data - meta ApiErrorMetaSchema: properties: next_steps: $ref: '#/components/schemas/NextStepsSchema' request_id: type: string description: ULID-prefixed identifier for this request example: req_01HXYZ4K5ABCDEFGHJKLMNPQRS timestamp: type: string format: date-time example: '2026-05-14T15:43:55.732Z' version: type: string description: Major API version parsed from /vN/ example: '1' type: object required: - next_steps - request_id - timestamp - version NextStepsSchema: properties: action: type: string description: Suggested action for the caller example: Verify the resource identifier and retry. docs_url: type: string format: uri example: https://docs.globalstack.io/errors#not_found type: object required: - action - docs_url securitySchemes: BearerAuth: type: http scheme: bearer description: API key issued during merchant onboarding. ````