> ## Documentation Index > Fetch the complete documentation index at: https://docs.agentcard.com/llms.txt > Use this file to discover all available pages before exploring further. # Refund a charge > Refund a cleared charge on a sandbox card. Refunds a cleared charge. As on a live card, the refund arrives as a new transaction with a negative amount, so your code has to handle one. ## OpenAPI ````yaml openapi.json POST /api/v2/cards/{card_id}/test_transactions/{transaction_id}/refund openapi: 3.1.0 info: title: Agentcard API version: 2.0.0 description: >- The Agentcard v2 API — connect your users and verify their identity from your own backend. Every call is authenticated with a platform access token minted from your `client_id` + `client_secret`. servers: - url: https://api.agentcard.sh description: >- There is one base URL. Sandbox vs production is decided by the client credential you use, never by the host. security: - platformToken: [] tags: - name: Authentication description: >- Exchange your client credentials for a platform access token, and introspect what a token acts as. - name: Connect description: >- Connect a user to your platform: send a one-time code, verify it, record consent, and keep the connection alive. - name: Identity verification description: >- Verify a connected user's identity: upload their ID, submit any extra fields we ask for, then show a short face scan. paths: /api/v2/cards/{card_id}/test_transactions/{transaction_id}/refund: post: tags: - Cards summary: Refund a charge description: >- Sandbox only. Refunds a cleared transaction, for all of it or part. As on a live card, the refund arrives as a new transaction with a negative amount, and sends `transaction.cleared`. The original transaction doesn't change. operationId: cardTestRefund parameters: - name: card_id in: path required: true schema: type: string - name: transaction_id in: path required: true schema: type: string requestBody: required: false content: application/json: schema: type: object additionalProperties: false properties: amount_cents: type: integer minimum: 1 description: Defaults to the full charge. responses: '201': description: The new refund transaction. content: application/json: schema: $ref: '#/components/schemas/TestTransaction' '401': $ref: '#/components/responses/Unauthorized' '403': description: >- `sandbox_only`: you sent a production credential. Real merchants charge live cards. content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: >- `card_not_found` or `transaction_not_found`: no such card, or no simulated transaction with that id on it. content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: >- `invalid_transaction_state`: the transaction isn't in a state this call accepts. content: application/json: schema: $ref: '#/components/schemas/Error' security: - platformToken: [] components: schemas: TestTransaction: type: object required: - object - id - card_id - amount_cents - merchant - status - simulated - events - card properties: object: type: string const: test_transaction id: type: string card_id: type: string amount_cents: type: integer description: Negative on a refund. merchant: type: string mcc: type: string status: type: string enum: - authorized - cleared - declined - voided - refunded decline_reason: type: string original_transaction_id: type: string description: On a refund, the transaction it refunds. simulated: type: boolean const: true events: type: array items: type: string description: The webhook events this call sent. card: $ref: '#/components/schemas/Card' Error: type: object description: Every v2 error uses the same envelope. properties: error: type: object properties: code: type: string description: A stable, machine-readable string (snake_case). Branch on this. message: type: string description: A human-readable explanation, safe to log. docs: type: string description: A link back to the reference. field_errors: type: object additionalProperties: type: string description: Only on `invalid_fields` — names each field to fix. warnings: type: array items: type: string description: >- Only on document upload errors — actionable feedback safe to show the user. Card: type: object required: - object - id - status - spend_limit_cents - balance_cents - last4 - expiry - type - created_at properties: object: type: string description: Always `card`. enum: - card id: type: string description: The card's id. status: type: string description: >- `creating`, `open`, `in_use`, `paused`, `pausing`, `closing`, or `closed`. type: type: string description: '`single_use` or `multi_use`.' spend_limit_cents: type: integer description: What the card can spend in all. balance_cents: type: integer description: What's left to spend. last4: type: string description: The last four digits. expiry: type: string description: '`MM/YY`.' user_id: type: - string - 'null' description: The user the card is for. cardholder_name: type: string description: The name the card was issued in, for the payment form. billing_address: type: string description: The billing address, for the payment form. funds_source: type: string description: 'On a new card: what funded it.' transfer_id: type: string description: 'On a company-funded new card: the transfer that funded it.' closed_reason: type: string description: 'Only when `closed`: `used`, `canceled`, `expired`, `declined`.' card_expires_at: type: string description: When a `multi_use` card closes itself. format: date-time created_at: type: string description: When it was issued. format: date-time responses: Unauthorized: description: >- `unauthorized` — the platform access token is missing or expired. Exchange your client credentials for a fresh one. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: platformToken: type: http scheme: bearer description: >- A platform access token. Get one on the **Create an access token** endpoint by exchanging your `client_id` + `client_secret`, then send it as `Authorization: Bearer `. Tokens live one hour. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.