{"section":"known-issues","requestedLocale":"en","requestedSlug":"creating-custom-fields-for-custom-data-converts-the-ids-to-lowercase","locale":"en","slug":"creating-custom-fields-for-custom-data-converts-the-ids-to-lowercase","path":"docs/en/known-issues/Shopping/creating-custom-fields-for-custom-data-converts-the-ids-to-lowercase.md","branch":"main","content":"## Summary\n\nBy creating \"custom fields\" in the \"custom data\" section through the checkout API, the IDs of the reported apps are converted to lowercase letters.\n\n## Simulation\n\n1. Use the [POST Update Custom Fields](https://documenter.getpostman.com/view/18468/vtex-checkout-api/6Z2QYJM#dc90afae-a4e5-59c5-1854-fc0fa81c99ee) API;\n2. Send an \"app\" that has an \"ID\" with an uppercase letter (for example, \"customFieldTest\");\n3. Note in the response of the request that the \"ID\" was converted to lowercase letters (in the example above, it would be \"customfieldtest\").\n\n## Workaround\n\nCurrently this is an API restriction. It's not possible to get around this scenario. Custom Data Custom Fields must be used with lowercase letters."}