Funding Source

A card’s fundingSource is the internal account Authorization Decisioning pulls from when an auth lands. Every card is bound to exactly one. This page covers binding at issue time and replacing the binding via PATCH /cards/{id}.

At issue time

You supply fundingSource on POST /cards.

curl -X POST "$GRID_BASE_URL/cards" \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "customerId": "Customer:019542f5-b3e7-1d02-0000-000000000001",
    "form": "VIRTUAL",
    "fundingSource": "InternalAccount:019542f5-b3e7-1d02-0000-000000000002"
  }'

The account must:

Belong to the cardholder (no cross-customer funding in v1).
Be denominated in a card-eligible currency (USDB in v1).

The card’s currency is derived from the funding source at issue time. The funding source also selects the card issuer, and therefore the card’s cardCapabilities. If the account fails these checks, the request is rejected with 400 FUNDING_SOURCE_INELIGIBLE.

Replacing the binding

PATCH /cards/{id} accepts a fundingSource field that replaces the account the card draws on.

curl -X PATCH "$GRID_BASE_URL/cards/Card:019542f5-b3e7-1d02-0000-000000000010" \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "fundingSource": "InternalAccount:019542f5-b3e7-1d02-0000-000000000003"
  }'

The replacement account must belong to the cardholder and be denominated in the card’s currency. The response is 200 OK with the updated Card. On card programs where the card issuer makes the authorization decision, fundingSource cannot be combined with a state change — send them as separate requests. Where Grid makes the decision, the combination is valid for any state change other than CLOSED.

Errors

Status	Code	What it means
400	`FUNDING_SOURCE_INELIGIBLE`	The account doesn’t belong to the cardholder or isn’t denominated in the card’s currency.
400	`INVALID_INPUT`	`fundingSource` was supplied alongside `state: CLOSED`, or combined with a `state` change on a card program where the card issuer decides authorizations.
409	`CARD_NOT_MUTABLE`	The card is `CLOSED`.

Stopping a card from spending

A card always has a funding source — you cannot unbind one. To stop a card from spending without changing what funds it, transition it to FROZEN:

curl -X PATCH "$GRID_BASE_URL/cards/Card:019542f5-b3e7-1d02-0000-000000000010" \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{ "state": "FROZEN" }'

To permanently retire a card, close it with PATCH /cards/{id} and state: "CLOSED". Closing detaches the funding source; fundingSource cannot be supplied in the same request.

Overview

Onboarding

Card management

Transactions

Card design

Platform tools

At issue time

Replacing the binding

Errors

Stopping a card from spending

​At issue time

​Replacing the binding

​Errors

​Stopping a card from spending

At issue time

Replacing the binding

Errors

Stopping a card from spending