How to use Go Error Wrapping Helper
Paste your input on the left, choose the options you want, and the output appears instantly on the right. Everything runs in your browser — none of your data is sent to a server.
- Paste or type your input in the
INPUTpanel - The output regenerates automatically as you type
- Use
Copyto put the result in your clipboard - Click
Sampleto load a working example
What is Go Error Wrapping Helper?
Type a context phrase ("fetching user", "invalid JSON") and get ready-to-paste snippets for all 5 common Go error-handling idioms: wrapped errors with %w (Go 1.13+), simple errors.New, sentinel error declarations, custom error types with Unwrap(), and the full function pattern. Helps maintain consistent error handling across your codebase. This tool is part of santekno's developer toolbox — a curated collection of utilities built for engineers who care about speed, privacy, and simplicity.
Common use cases
- Debugging API payloads and integration issues
- Inspecting tokens, hashes, or encoded strings during development
- Generating fixtures and sample data for tests
- Sharing readable output with teammates in code reviews
FAQ
Use %w to wrap the original error (preserves it for errors.Is/errors.As). Use %v if you only want the message and don't need to unwrap.
A package-level error variable (e.g. var ErrNotFound = errors.New(...)). Callers compare with errors.Is(err, pkg.ErrNotFound).
When the error needs structured data (e.g. validation fields, HTTP status). Use errors.As to extract it: var e *MyError; if errors.As(err, &e) { ... }.
Wrap when the caller might need to inspect the underlying error. Skip wrapping for terminal errors that callers will only log.
Use errors.Is(err, sentinelErr) to compare, or errors.As(err, &targetType) to extract typed errors. Both walk the wrap chain.