Subchapter 4.10

Error Codes

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All errors exit with code 1 and output JSON to stderr:

{"error":{"message":"Human-readable description","code":"error_code"}}

Authentication Errors

Error Codes · Resend CLI · resend/resend-skills · Skills Docs

Code	Cause	Resolution
`auth_error`	No API key found from any source	Set `RESEND_API_KEY` env or run `resend login`
`missing_key`	`login` called non-interactively without `--key`	Pass `--key "$RESEND_API_KEY"` (from env/secret manager, never a literal)
`invalid_key_format`	API key does not start with `re_`	Use a valid Resend API key starting with `re_`
`validation_failed`	Resend API rejected the key during login	Verify the key exists and is active at resend.com/api-keys

Code	Cause	Resolution
`missing_body`	None of `--text`, `--html`, `--html-file`, or `--react-email` provided	Provide at least one body flag
`react_email_build_error`	Failed to bundle a React Email `.tsx` template with esbuild	Check the template compiles; ensure `react` and one of `react-email` (6.0+), `@react-email/components` (5.x), or `@react-email/render` are installed in the project
`react_email_render_error`	Bundled template failed during `render()`	Check the component exports a default function and renders valid React Email markup
`file_read_error`	Could not read file from a `--file`/`--html-file`/`--text-file` path	Check file path exists and is readable
`send_error`	Resend API rejected the send request	Check from address is on a verified domain; check recipient is valid

Code	Cause	Resolution
`missing_file`	`contacts imports create` called non-interactively without `--file`	Pass `--file <path>` to the CSV to import
`invalid_column_map`	`--column-map` is not valid JSON, or is not an object	Pass a JSON object mapping contact fields to CSV headers, e.g. `{"email":"Email"}`
`invalid_topics`	`--topics` is not valid JSON, or is not an array	Pass a JSON array of `{id, subscription}` objects
`create_error`	Resend API rejected the import (e.g. CSV missing the required `email` column, or file over 100MB)	Ensure the CSV has an `email` column (or map it with `--column-map`) and is under 100MB

Code	Cause	Resolution
`domain_error`	Domain creation, verification, or update failed	Check domain name is valid; check DNS records are configured

Code	Cause	Resolution
`unexpected_error`	Unhandled exception	Check CLI version with `resend update`; report at github.com/resend/resend-cli/issues
`unknown`	Error without a specific code	Inspect the `message` field for details