> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fyatu.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Fund Card
> Load funds from your program ledger onto a card. POST /cards/{id}/fund. Requires cards:write scope.
## Overview
Transfers funds from your **program ledger** to a specific card. The program ledger balance decreases by the funded amount; the card becomes spendable once the provider confirms the fund.
The card must be `ACTIVE` — you cannot fund a `FROZEN` or `TERMINATED` card.
**Funding is asynchronous.** A successful (`2xx`) response means the request was **accepted and is pending confirmation from the card provider** — the fund is **not final** and may still be **rejected**. The funding transaction stays `PENDING` until the provider confirms it. Use the [`CARD_FUNDED`](/v3.20/webhooks/events/card-funded) (confirmed — card credited) and [`CARD_FUND_FAILED`](/v3.20/webhooks/events/card-fund-failed) (rejected — program ledger refunded) webhooks as the source of truth. Both echo the caller `reference` you supplied for reconciliation.
## Path Parameters
| Parameter | Type | Description |
| --------- | ------ | --------------------------- |
| `id` | string | The card ID (prefix `crd_`) |
## Request Body
| Field | Type | Required | Description |
| ----------- | ------ | -------- | ----------------------------------------------------------------------------------------------------- |
| `amount` | number | Yes | Amount in full currency units (e.g. `50.00` = \$50). Must be greater than 0. |
| `reference` | string | No | Optional caller-supplied reference (order ID, batch ID, etc.) echoed back in the response and webhook |
## Idempotency
Funding is idempotent on the **`reference`** field. If you retry a fund with the same
`reference` for the same card, the API returns the **original** result and does **not** debit
your program balance or fund the card again — a client retry or accidental double-submit can
never double-charge. Always send a stable, unique `reference` per logical fund.
## Example
```bash cURL theme={null}
curl -X POST https://api.fyatu.com/api/v3.20/cards/crd_01HXYZ5555ABCDEF1111/fund \
-H "Authorization: Bearer $FYATU_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "amount": 50.00, "reference": "order-001" }'
```
```javascript Node.js theme={null}
const resp = await fetch(
'https://api.fyatu.com/api/v3.20/cards/crd_01HXYZ5555ABCDEF1111/fund',
{
method: 'POST',
headers: {
'Authorization': `Bearer ${process.env.FYATU_API_KEY}`,
'Content-Type': 'application/json'
},
body: JSON.stringify({ amount: 50.00, reference: 'order-001' })
}
);
const body = await resp.json();
console.log('Loaded:', body.data.amount); // 50
console.log('Transaction:', body.data.transactionId);
```
```python Python theme={null}
import os, requests
resp = requests.post(
'https://api.fyatu.com/api/v3.20/cards/crd_01HXYZ5555ABCDEF1111/fund',
headers={'Authorization': f'Bearer {os.environ["FYATU_API_KEY"]}'},
json={'amount': 50.00, 'reference': 'order-001'}
)
data = resp.json()['data']
print('Loaded:', data['amount'])
print('Transaction:', data['transactionId'])
```
## Success Response (200)
```json theme={null}
{
"success": true,
"status": 200,
"message": "Card funded",
"data": {
"cardId": "crd_01HXYZ5555ABCDEF1111",
"amount": 50.00,
"currency": "USD",
"reference": "order-001",
"transactionId": "ltx_01HXYZ9999ABCDEF2222"
},
"meta": {
"requestId": "req_01HXY123456ABCDEF",
"platform": "Fyatu CaaS",
"timestamp": "2026-05-26T10:00:00Z"
}
}
```
## Webhook
A `CARD_FUNDED` event fires after a successful funding:
```json theme={null}
{
"event": "CARD_FUNDED",
"eventId": "evt_01HXY123456ABCDEF",
"businessId": "BUS1A2B3C4D5E6F",
"environment": "LIVE",
"timestamp": "2026-05-26T10:00:00Z",
"data": {
"cardId": "crd_01HXYZ5555ABCDEF1111",
"amount": 50.00,
"currency": "USD",
"reference": "order-001",
"transactionId": "ltx_01HXYZ9999ABCDEF2222",
"timestamp": "2026-05-26T10:00:00Z"
}
}
```
## Error Codes
| Code | HTTP | Cause |
| ------------------------------ | ---- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `CARD_NOT_FOUND` | 404 | Card does not exist or belongs to another business/environment |
| `CARD_FROZEN_CANNOT_FUND` | 422 | Card is frozen — unfreeze before funding |
| `CARD_ALREADY_TERMINATED` | 422 | Card is already terminated |
| `INSUFFICIENT_PROGRAM_BALANCE` | 422 | Program ledger balance is too low — top up your program balance |
| `INVALID_AMOUNT` | 400 | Amount is zero, negative, or exceeds the program load cap |
| `PROVIDER_FUND_FAILED` | 422 | The card provider rejected the funding for a specific, actionable reason (returned in `error.detail`, e.g. an amount cap) — ledger has been reverted |
| `CARD_FUNDING_UNAVAILABLE` | 503 | Card funding is temporarily unavailable — either paused by Fyatu, or a transient processing issue on our side. Your program balance is **not** affected; retry later. |
| `INSUFFICIENT_SCOPE` | 403 | Key lacks `cards:write` scope |
`CARD_FUNDING_UNAVAILABLE` is a **transient** condition, not a problem with your request or balance —
treat it as retryable (with backoff). It is distinct from `INSUFFICIENT_PROGRAM_BALANCE`, which means
*your* program balance is too low and requires a top-up.
## OpenAPI
````yaml v3.20/openapi.json POST /cards/{id}/fund
openapi: 3.1.0
info:
title: FYATU CaaS API v3.20
description: >-
FYATU Cards-as-a-Service API — API key authentication, Cardholder
lifecycle, Card issuance, Transactions, Webhooks, and Programs.
version: 3.20.0
contact:
name: FYATU Support
url: https://fyatu.com
email: support@fyatu.com
servers:
- url: https://api.fyatu.com/api/v3.20
description: >-
FYATU CaaS API — the environment (LIVE or SANDBOX) is determined by the
API key, not the URL
security:
- BearerAuth: []
tags:
- name: Meta
description: Liveness, account info, and supported event types
- name: Account
description: Account-level balance and funding status
- name: Programs
description: Read card program configuration
- name: Cardholders
description: Create and manage cardholder profiles
- name: Cards
description: Issue, fund, freeze, and terminate virtual cards
- name: Transactions
description: Read-only card transaction history
- name: Webhooks
description: Manage webhook endpoints for real-time event delivery
- name: Products
description: Read card product configurations
paths:
/cards/{id}/fund:
post:
tags:
- Cards
summary: Fund a card
description: >-
Load funds from the program ledger onto a card. Card must be ACTIVE.
Amount in full currency units (e.g. `50.00`).
operationId: fundCard
parameters:
- name: id
in: path
required: true
schema:
type: string
example: crd_01HXYZ5555ABCDEF1111
requestBody:
required: true
content:
application/json:
schema:
type: object
required:
- amount
properties:
amount:
type: number
format: double
example: 50
reference:
type: string
example: order-001
responses:
'200':
description: Card funded
content:
application/json:
schema:
$ref: '#/components/schemas/CardFundResponse'
example:
success: true
status: 200
message: Card funded
data:
cardId: crd_01HXYZ5555ABCDEF1111
amount: 50
currency: USD
reference: order-001
transactionId: ltx_01HXYZ9999ABCDEF2222
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-26T10:00:00Z'
'400':
$ref: '#/components/responses/ValidationError'
'401':
$ref: '#/components/responses/Unauthorized'
'403':
$ref: '#/components/responses/Forbidden'
'404':
$ref: '#/components/responses/NotFound'
'422':
description: Insufficient program balance or card cannot be funded
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
examples:
insufficientBalance:
value:
success: false
status: 422
message: Insufficient program balance
error:
code: INSUFFICIENT_PROGRAM_BALANCE
detail: Insufficient program balance
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
cardFrozen:
value:
success: false
status: 422
message: Cannot fund a frozen card
error:
code: CARD_FROZEN_CANNOT_FUND
detail: Cannot fund a frozen card
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
'429':
$ref: '#/components/responses/RateLimitExceeded'
'500':
$ref: '#/components/responses/InternalError'
components:
schemas:
CardFundResponse:
type: object
properties:
success:
type: boolean
example: true
status:
type: integer
example: 200
message:
type: string
example: Card funded
data:
type: object
properties:
cardId:
type: string
example: crd_01HXYZ5555ABCDEF1111
amount:
type: number
description: Amount funded in full currency units
example: 50
currency:
type: string
example: USD
reference:
type: string
description: Caller-supplied reference echoed back
example: order-001
transactionId:
type: string
example: ltx_01HXYZ9999ABCDEF2222
meta:
$ref: '#/components/schemas/Meta'
Error:
type: object
properties:
success:
type: boolean
example: false
status:
type: integer
example: 422
message:
type: string
example: Human readable message
error:
$ref: '#/components/schemas/ErrorBody'
meta:
$ref: '#/components/schemas/Meta'
Meta:
type: object
properties:
requestId:
type: string
example: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform:
type: string
example: Fyatu CaaS
timestamp:
type: string
format: date-time
example: '2026-05-22T15:00:00Z'
ErrorBody:
type: object
properties:
code:
type: string
example: VALIDATION_ERROR
detail:
type: string
example: dateOfBirth must be in YYYY-MM-DD format
responses:
ValidationError:
description: Request validation failed
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
success: false
status: 422
message: Validation failed
error:
code: VALIDATION_ERROR
detail: dateOfBirth must be in YYYY-MM-DD format
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
Unauthorized:
description: Missing or invalid API key
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
examples:
missing:
summary: API key missing
value:
success: false
status: 401
message: API key is required
error:
code: AUTH_TOKEN_MISSING
detail: API key is required
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
invalid:
summary: API key invalid
value:
success: false
status: 401
message: Invalid API key
error:
code: AUTH_TOKEN_INVALID
detail: Invalid API key
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
Forbidden:
description: Scope denied or business suspended
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
success: false
status: 403
message: Scope denied
error:
code: INSUFFICIENT_SCOPE
detail: This endpoint requires the cards:write scope
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
NotFound:
description: Resource not found or does not belong to your business
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
RateLimitExceeded:
description: Rate limit exceeded
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
success: false
status: 429
message: Rate limit exceeded
error:
code: RATE_LIMIT_EXCEEDED
detail: Too many requests
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
InternalError:
description: Unexpected server error
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
success: false
status: 500
message: Internal error
error:
code: INTERNAL_ERROR
detail: An unexpected error occurred
meta:
requestId: req_a1b2c3d4e5f6a7b8c9d0e1f2
platform: Fyatu CaaS
timestamp: '2026-05-22T15:00:00Z'
securitySchemes:
BearerAuth:
type: http
scheme: bearer
description: >-
API key from the FYATU CaaS portal. Pass as `Authorization: Bearer
`.
````