# Start a monthly plan (Stripe Checkout)

Billing

POST `/v1/billing/subscription/checkout`

Creates a Stripe Checkout session that starts a monthly plan; open the returned url to pay. The plan's credits are added when the first payment completes, and again at each renewal, when what was left of them ends. GET /v1/billing/checkout/{id} follows it. An account already on a plan changes it with PATCH /v1/billing/subscription instead. The dashboard session only: it starts recurring charges. Free.

**Auth:** the dashboard session cookie.

Send an `idempotency-key` header to retry safely: the same key and body within 1 day never repeat the work.

## Example

cURL:

```shell
curl -X POST 'https://socialtap.dev/v1/billing/subscription/checkout' \
  -H "x-api-key: $SOCIALTAP_API_KEY" \
  -H "content-type: application/json" \
  -d '{
  "plan": "string"
}'
```

## Authorizations

The dashboard's session cookie, not an API key.

## Headers

| Name | Type | Description | Example |
| --- | --- | --- | --- |
| `idempotency-key` optional | `string`<br>max 255 chars | On any POST: your unique key for the request (1–255 printable ASCII characters; a UUID is ideal), kept 24 hours. Retrying with the same key and body never repeats the work: the answer is the first request's result, in its current state. | — |

## Body

JSON. Fields marked nullable may be `null`; optional ones may be left out.

| Field | Type | Description |
| --- | --- | --- |
| `plan` | `string` | A public monthly plan's ID (catalog plans). |

## Response

### 200

Start a monthly plan (Stripe Checkout)

| Field | Type | Description |
| --- | --- | --- |
| `data` | `object` |  |
| `data.id` | `string` | Checkout session ID (cs_…); GET /v1/billing/checkout/{id} follows it. |
| `data.object` | `string` | Always checkout_session.<br>One of `checkout_session` |
| `data.url` | `string` | Stripe Checkout's page: open it to pay. |
| `meta` | `object` | The shared route meta (see the API reference introduction). |

### 400

400 Bad Request.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `invalid_input` | 400 | No | A parameter is missing or malformed, or the link is not one this endpoint takes. | Fix the parameter named in param as the message says. For a link of the wrong kind, call an endpoint listed in details.endpoints, when there is one. |

### 401

401 Unauthorized.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `unauthorized` | 401 | No | The x-api-key header is missing, or its key is unknown or revoked. On the dashboard's routes: the session cookie is missing or expired. | Send a valid API key in the x-api-key header. No key yet? A person gets one at details.signup_url; an AI agent follows details.agent_auth_url. |

### 403

403 Forbidden.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `forbidden` | 403 | No | The API key is valid but may not make this request, and details.reason says why: the account is suspended, the key lacks the route's scope, waits for its owner to confirm it by email, has expired, or was used from an IP outside its allowlist, or a rotated key's previous secret was used for a call that needs the admin scope. A running job stops with it too when its account is suspended or the key that created it is revoked or expires. It is about the key, never the item: a private item is private_or_unavailable, also 403, so branch on the code. | Act on details.reason. suspended: contact [support](mailto:support@socialtap.dev). scope: use a key with details.required_scope. previous_secret: use the new secret. key_pending: have the owner open the emailed link. key_expired or key_revoked: create a new key. ip_not_allowed: call from an allowed IP. |

### 409

409 Conflict.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `idempotency_key_in_progress` | 409 | Yes, later | A request with this Idempotency-Key is still running. | Retry after the seconds in the retry-after header to get that request's result. |

### 422

422 Unprocessable.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `idempotency_key_reused` | 422 | No | This Idempotency-Key was already used for a different request (another route or body). Or it was used for this same request, which ran and returned a secret we no longer keep (details.reason answer_expired): running it again would create another. | Use a new Idempotency-Key for a different request, and reuse a key only to retry the identical request. With reason answer_expired, check what the first request created (GET /v1/api_keys, GET /v1/webhook_endpoints) before sending it again under a new key. |

### 429

429 Too Many Requests.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `rate_limited` | 429 | Yes, later | The account passed its runaway-protection ceiling: a high per-account limit that stops a broken client loop (plans have no rate limit). Requests without an API key (signup, the MCP server's tool listing and find_endpoint) are limited per IP address instead. It also stops an account whose failed requests in the last hour cost far more than its successful ones paid for: failures are free within a limit (the message says so), and successes raise it. | Wait the seconds in the retry-after header, then retry. If your steady traffic needs more, ask [support](mailto:support@socialtap.dev) to raise the ceiling; without an API key, send one. |

### 502

502 Bad Gateway.

| Code | HTTP | Retry | Meaning | What to do |
| --- | --- | --- | --- | --- |
| `upstream_error` | 502 | Yes, later | The platform failed, or answered with something we could not read. | Retry with backoff. Failed requests are free. |

operationId `billing.subscription.checkout`

---

[HTML version](https://socialtap.dev/docs/reference/billing/subscription-checkout/) · [Docs index for AI agents](https://socialtap.dev/llms.txt) · [All docs in one file](https://socialtap.dev/llms-full.txt)