Affirm's APIs use conventional HTTP status codes to indicate the success or failure of API requests.

API calls successfully made to Affirm use codes in the 2xx range while codes in the 4xx range indicate failure and codes in the 5xx range internal server issues.

When an API call fails, the response body contains the error code, an error object, as well as additional information about the error to help you identify and resolve the issue.

Some 4xx errors that could be handled programmatically (e.g., a capture declined) include an error code that briefly explains the error reported.

Field names

KeyData typeDescription
status_codestringThe returned HTTP status code.
messagestringA friendly and human-readable message providing more details about the error.
codestringA short code reference for the specific error that can be used programmatically.
typestringThe type of error being returned that can be used programmatically.
fieldstringAn incorrect or invalid value.

Status codes

Charges endpoint status codes

Status codesError message
200 - successThe API call worked as expected.
400 - Bad requestThe request was improper. This is often due to missing information in the request fields.
401 - UnauthorizedNo valid API key provided
402 - Request failedThe parameters were valid but the request failed.
404 - Not foundThe requested resource could not be found.
409 - Conflict- Charges on this instrument cannot be captured for an amount that is greater than the total capturable balance.
- Charges on this instrument cannot be captured for an amount unequal to authorization hold amount.
- Charges on this instrument cannot be captured for an amount that is not equal to the total capturable balance.
-The transaction with this idempotency key is processing. Please wait to retry or use a different idempotency key.
500, 502, 503, 504 - Server ErrorsSomething went wrong on Affirm's end. Please check our status page.

Transactions endpoint status codes

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Expanded error handling

The Transactions API has specific error codes depending on the API call.

POST Capture Transaction

Status codeError message
403 - Forbidden error- The transaction cannot be captured or refunded while it is disputed.
- The idempotency key provided has already been used
- The transaction is past its capturable period and cannot be captured. Please contact [email protected] for assistance.
- The transaction has been voided and may no longer be captured.
- The transaction has already been voided.
- The transaction must be authorized before it may be captured.
404 - Not foundThe transaction could not be found.
409 - Conflict- Charges on this instrument cannot be captured for an amount that is greater than the total capturable balance.
- Charges on this instrument cannot be captured for an amount unequal to authorization hold amount.
- Charges on this instrument cannot be captured for an amount that is not equal to the total capturable balance.
-The transaction with this idempotency key is processing. Please wait to retry or use a different idempotency key.

POST Refund Transaction

Status codeError message
403 - Forbidden error- The transaction cannot be captured or refunded while it is disputed. - Refund amount is required for a partially refunded transaction. - The refund amount exceeds the remaining loan balance - The idempotency key provided has already been used. - This transaction cannot be refunded while the refund amount is negative. - The transaction is on the Virtual Card Network and may not be refunded by the Transaction API. - The transaction is authorized and may not be refunded. Try voiding the transaction instead. - The transaction has been voided and cannot be refunded. - The transaction is past its refundable period and cannot be refunded. Please contact [email protected] for assistance.
404 - Not foundThe transaction could not be found.
409 - ConflictThe transaction with this idempotency key is processing. Please wait to retry or use a different idempotency key.

POST Void Transaction

Status codeError message
403 - Forbidden error- The transaction cannot be captured or refunded while it is disputed. - Refund amount is required for a partially refunded transaction. - The refund amount exceeds the remaining loan balance - The idempotency key provided has already been used. - This transaction cannot be refunded while the refund amount is negative. - The transaction is on the Virtual Card Network and may not be refunded by the Transaction API. - The transaction is authorized and may not be refunded. Try voiding the transaction instead. - The transaction has been voided and cannot be refunded. - The transaction is past its refundable period and cannot be refunded. Please contact [email protected] for assistance.
404 - Not foundThe transaction could not be found.
409 - Conflict- Void amount is not allowed for a merchant not supporting split capture. - The total amount to be voided cannot be greater than the total capturable balance. - The transaction with this idempotency key is processing. Please wait to retry or use a different idempotency key.

Error types

Error typesDescription
unauthorizedInvalid API keys provided.
invalid_requestA generic error that indicates invalid request inputs.

Error codes

Error codesDescription
auth-declinedCharge authorization hold declined.
capture-greater-instrumentCannot capture charges on this instrument for more than the authorization hold amount.
capture-unequal-instrumentCannot capture charges on this instrument for an amount unequal to the authorization hold amount.
capture-voidedCannot capture voided charge.
partial-capture-instrumentCannot partially capture charges on this instrument.
refund-exceededExceeded maximum refund.
refund-uncapturedCannot refund a charge that hasn't been captured.
refund-voidedCannot refund a voided charge.
capture-declinedCharge capture declined.
capture-limit-exceededExceed maximum capture amount on charge.
expired-authorizationCannot capture a charge with an expired authorization hold.
refund-expiredCharges on this instrument must be refunded within N days of capture.
invalid_fieldAn input field resulted in invalid request.
public-api-key-not-specifiedPlease provide a public API key.
public-api-key-invalidPlease provide a valid public API key.
public-api-key-wrong-environmentPlease provide a live public API key when not using the sandbox environment.
public-api-key-inactivePlease provide an active public API key.
api-key-pair-not-specifiedPlease provide an API key pair.
private-api-key-invalidPlease provide a valid private API key.
api-key-pair-wrong-environmentPlease provide a live API key pair when not using the sandbox environment.
api-key-pair-inactivePlease provide an active API key pair.
not_foundCould not find the resource(s) specified in the request.