---
title: "Attach card to trial account"
method: POST
path: "/v1/cards/attach"
tags: ["Account"]
---

# Attach card to trial account

`POST /v1/cards/attach`

Attach a payment card to a cardless trial organization using a single-use Stripe shared payment token. The card is verified with a temporary $1 authorization that is refunded immediately (net cost $0), and the organization's free-credit ceiling is raised. The verified card is not saved for future charges — every future paid top-up requires a freshly-minted shared payment token.

<span>⚡ <strong>Rate limit:</strong> 3 requests per 1 minute</span>

<span>💰 <strong>Cost:</strong> FREE! No credits are charged for this API.&nbsp;<span title="Pricing shown is default pricing. Actual pricing may vary.">ⓘ</span></span>

## Request body

- object
  - `apiKey` string, required — Your Fiber API key
  - `sharedPaymentGrantedToken` string, required — Single-use Stripe shared payment token (`spt_...`) authorizing exactly one card handoff. Mint it on the buyer side (see https://docs.stripe.com/agentic-commerce/concepts/shared-payment-tokens); each request must submit a freshly-minted token.

## Response `200`

Default Response

- object
  - `output` object, required
    - `status` 'attached', required
    - `creditsGranted` integer, required — Additional free trial credits granted by this call. Zero when the organization was already at its trial credit ceiling (e.g. re-attaching after the ceiling was already reached).
    - `totalCreditsUnlocked` integer, required — Free trial credit ceiling after this call — the maximum credits the organization can spend on the trial before it needs a paid top-up.
    - `paymentMethod` object, required — Display-only metadata for the card that was verified in this call. This is not a saved payment method — future paid top-ups must submit a freshly-minted shared payment token.
      - `brand` string, nullable — Card network (e.g. 'visa', 'mastercard'). Null when unavailable.
      - `last4` string, nullable — Last four digits of the card. Null when unavailable.
  - `chargeInfo` union, required
    - object — Credits were charged immediately for this operation
      - `method` 'charged-now', required
      - `creditsCharged` number, required
      - `lowCreditAlert` object, nullable — Contains a link to get more credits, a warning message, and the remaining credit count.
        - `getMoreCreditsUrl` string, uri, required — URL to top up credits or restart billing cycle to get fresh credits.
        - `message` string, required — Human-readable credits warning.
        - `availableCredits` number, required — Number of credits remaining in the current billing period.
    - object — Credits will be charged after the operation completes
      - `method` 'charging-later', required
      - `message` string, required
      - `lowCreditAlert` object, nullable — Contains a link to get more credits, a warning message, and the remaining credit count.
        - `getMoreCreditsUrl` string, uri, required — URL to top up credits or restart billing cycle to get fresh credits.
        - `message` string, required — Human-readable credits warning.
        - `availableCredits` number, required — Number of credits remaining in the current billing period.
    - object — Credits that were charged for an asynchronous operation
      - `method` 'charged-for-async-process', required
      - `creditsCharged` number, required
      - `message` string, required
      - `lowCreditAlert` object, nullable — Contains a link to get more credits, a warning message, and the remaining credit count.
        - `getMoreCreditsUrl` string, uri, required — URL to top up credits or restart billing cycle to get fresh credits.
        - `message` string, required — Human-readable credits warning.
        - `availableCredits` number, required — Number of credits remaining in the current billing period.
    - object — No credits were charged for this operation
      - `method` 'free', required
      - `message` string, required
      - `lowCreditAlert` object, nullable — Contains a link to get more credits, a warning message, and the remaining credit count.
        - `getMoreCreditsUrl` string, uri, required — URL to top up credits or restart billing cycle to get fresh credits.
        - `message` string, required — Human-readable credits warning.
        - `availableCredits` number, required — Number of credits remaining in the current billing period.
    - object — Credits were refunded for this operation
      - `method` 'credits-refunded', required
      - `creditsRefunded` number, required
      - `message` string, required
      - `lowCreditAlert` object, nullable — Contains a link to get more credits, a warning message, and the remaining credit count.
        - `getMoreCreditsUrl` string, uri, required — URL to top up credits or restart billing cycle to get fresh credits.
        - `message` string, required — Human-readable credits warning.
        - `availableCredits` number, required — Number of credits remaining in the current billing period.
  - `warnings` object[], nullable — Warnings about extraneous fields in request
    - `field` string, required — Full path to extraneous field (e.g., 'searchParams.ExtraField')
    - `message` string, required — Warning message
  - `advice` string[], nullable — Tips, recommendations, and suggestions for using this API effectively.

## Other responses

- `400` — Default Response
- `401` — Default Response
- `402` — Default Response
- `403` — Default Response
- `404` — Default Response
- `409` — Default Response
- `422` — Default Response
- `429` — Default Response
- `500` — Default Response
- `503` — Default Response

---

[API](https://skmtc.net/fiber/apis/fiber-ai-api.md) · [All operations](https://skmtc.net/fiber/apis/fiber-ai-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/fiber/fiber-ai-api/revisions/87ad9a3ecc4c/schema)