Keywords: FastStore | API extension | GraphQL | schema extensions | yarn generate | deploy preview

Although the FastStore API provides a GraphQL schema for ecommerce, you can extend it to access other or more specific information from your store. During this implementation, you may encounter issues such as local GraphQL changes not being reflected, schema differences between environments, or generation errors.

If your GraphQL changes aren't visible during development, or if your deploy preview or production schema differs from the development one, the GraphQL layer likely needs optimization. This process ensures your latest code changes are reflected in the generated schema and types.

1. Run yarn generate (recommended) or yarn run faststore generate-graphql in the project root.

You can run yarn generate while the development server is running.

2. If changes still aren't visible, or if differences between development and deploy preview/production persist, stop yarn dev and start it again.

If changes are visible in development but not in the deploy preview or production, verify deployment inputs and build context.

1. Confirm all API Extensions changes are committed to the deployed branch.
2. Confirm the deploy preview/production build was triggered from the same branch and latest commit.
3. Re-run yarn generate (or yarn run faststore generate-graphql) locally and compare local behavior with the deployed result.

If you see errors or warnings during generation, use the table below to identify the issue and the required action.

Issue	Description	Solutions
error Failed to run 'yarn generate:schema'. Please check your setup.	Schema generation failed, usually due to invalid schema extension files.	Review .graphql files in src/graphql/vtex/typeDefs and src/graphql/thirdParty/typeDefs for syntax and schema definition issues.
error GraphQL was not optimized, and TS files were not updated. Changes in the GraphQL layer didn't take effect.	GraphQL optimization failed, usually due to invalid schema, resolvers, queries, or fragments.	Validate schema files, resolver files in src/graphql/(vtex or thirdParty)/resolvers, and query or fragment declarations in .ts and .tsx files.
warn Failed to format generated files. 'yarn format:generated' threw errors.	Formatting step failed after generation.	This is a warning, not an error. Your GraphQL layer will still function correctly. If you want to investigate and resolve the formatting issue, follow these steps: 1. Retry formatting: Run the yarn format:generated command again. 2. Check formatting configuration: Ensure formatting rules are correct and compatible with the generated files. 3. Inspect error logs: Look for specific error messages for more clues about the issue.

If the issue isn't clear from the messages above, run the generation command with debug output to identify exactly where the failure occurs.

1. Run yarn generate --debug.
2. Use the verbose output to identify the failing file or operation.