# Codes

This section covers the different codes you can encounter when integrating with Checkout.com's APIs.

Review  the supported formats for data elements like countries and currencies, along with descriptions of our API response codes.

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## Related topics

- [3DS SDK error codes](https://www.checkout.com/docs/developer-resources/codes/3ds-sdk-error-codes.md): View the error codes returned by the 3DS SDKs for Android and iOS.
- [ANI codes](https://www.checkout.com/docs/developer-resources/codes/ani-codes.md): View the reference for codes returned with Account Name Inquiry checks.
- [API response codes](https://www.checkout.com/docs/developer-resources/codes/api-response-codes.md): View the reference for the response codes you can receive about the status of an API request.
- [AVS codes](https://www.checkout.com/docs/developer-resources/codes/avs-codes.md): View the reference for the codes returned by Address Verification Service (AVS) checks.
- [Chargeback codes](https://www.checkout.com/docs/developer-resources/codes/chargeback-codes.md): View the reference for the chargeback codes you can receive during the chargeback process.
- [Country codes](https://www.checkout.com/docs/developer-resources/codes/country-codes.md): View the reference for ITU-T E.164 dialing codes, alpha-2 ISO 3166 country codes, and alpha-3 ISO 3166 country codes.
- [Currency codes](https://www.checkout.com/docs/developer-resources/codes/currency-codes.md): View the reference for ISO 4217 currency codes.
- [CVV response codes](https://www.checkout.com/docs/developer-resources/codes/cvv-response-codes.md): View the reference for the card verification value (CVV) response codes you can receive when you carry out a CVV check or verify a card.
- [ECI values](https://www.checkout.com/docs/developer-resources/codes/eci-values.md): View the reference for Electronic Commerce Indicator (ECI) values that indicate 3D Secure (3DS) authentication level and liability shift.
- [Error codes](https://www.checkout.com/docs/developer-resources/codes/error-codes.md): View the reference for the error codes you can receive if there is an issue with your API request.
- [Identities codes](https://www.checkout.com/docs/developer-resources/codes/identities-codes.md): View the reference for the statuses, response codes, and risk codes you can receive for Identities products.
- [Issuing decline codes](https://www.checkout.com/docs/developer-resources/codes/issuing-decline-codes.md): View the reference for decline reason codes you can receive when a transaction from a card you issued fails.
- [Issuing dispute codes](https://www.checkout.com/docs/developer-resources/codes/issuing-dispute-codes.md): View the reference for the reason codes you can receive for Issuing disputes.
- [Merchant category codes](https://www.checkout.com/docs/developer-resources/codes/merchant-category-codes.md): View the reference for the ISO 18245 merchant category codes used to classify your business.
- [Network token provisioning codes](https://www.checkout.com/docs/developer-resources/codes/network-token-provisioning-codes.md): View the reference for card scheme response codes you can receive for network token provisioning requests.
- [Real-Time Account Updater response codes](https://www.checkout.com/docs/developer-resources/codes/real-time-account-updater-response-codes.md): View the reference for the response codes you can receive when requesting a card update with Real-Time Account Updater.
- [Recommendation codes](https://www.checkout.com/docs/developer-resources/codes/recommendation-codes.md): View the reference for recommendation codes about how and when to retry Mastercard and Visa payments.
- [Risk property codes](https://www.checkout.com/docs/developer-resources/codes/risk-property-codes.md): Use properties to create your Fraud Detection risk rules.
- [Scheme fraud codes](https://www.checkout.com/docs/developer-resources/codes/scheme-fraud-codes.md): View the reference for the definitions of fraud codes you can receive when processing Visa and Mastercard payments.
- [Visa response codes](https://www.checkout.com/docs/developer-resources/codes/visa-response-codes.md): View the reference for the response codes Visa returns to inform you if and when to retry transactions.