github.com/evanw/esbuild

The esbuild Go API is refreshingly straightforward once you understand the core concepts. The `api.Build()` function takes a well-structured `BuildOptions` struct that maps cleanly to CLI flags, making it easy to transition knowledge. Type safety is excellent—the Go structs guide you toward valid configurations, and the compiler catches many mistakes before runtime. Error handling follows standard Go patterns with clear error messages that typically point to the exact configuration issue.

The main friction point is documentation depth. While the package godoc is adequate, it often lacks context about why you'd use certain options or how they interact. You'll find yourself cross-referencing the main esbuild docs (written for CLI/JS users) to understand nuanced behaviors. The examples in the godoc are minimal—more realistic, complete examples would significantly improve the getting-started experience.

Performance is exceptional, and the API rarely changes in breaking ways between versions. Once you've built your first integration, extending it is intuitive. The plugin API exists but is limited compared to the JS version, which matters if you need deep customization.

esbuild is primarily a JavaScript/TypeScript bundler accessed via Go API. From a security perspective, its minimal design is both a strength and limitation. The codebase is lean with few dependencies, reducing supply chain risk significantly compared to npm-heavy alternatives. The Go implementation means you're not running arbitrary JavaScript during builds, which is a meaningful security improvement.

Error handling is straightforward but sometimes too silent - build failures don't always surface underlying issues like malformed imports or suspicious file access patterns. There's no built-in mechanism to restrict which files can be bundled or loaded, so you need external controls to prevent path traversal in build configs. The library doesn't validate or sanitize plugin inputs, expecting you to handle that upstream.

For authentication/authorization contexts, esbuild is purely a build tool with no network operations by default, which limits exposure. However, if you're using it in automated pipelines, ensure build configs come from trusted sources since esbuild will happily bundle whatever paths you specify without questioning intent.

Using esbuild's Go API directly gives you blazing fast bundling capabilities with a straightforward, struct-based configuration approach. The API surface is clean and predictable - you populate an `api.BuildOptions` struct and call `api.Build()`. Type safety is excellent with clear struct fields, and IDE completion works perfectly for discovering configuration options.

The main challenge is that documentation leans heavily on the CLI/JS docs, requiring translation to Go idioms. Error handling is functional but basic - you get error strings without structured error types for programmatic handling. The API is intentionally low-level, meaning you'll need to implement your own abstractions for plugin systems or watch mode patterns if your use case requires them.

For embedding a bundler directly into Go tooling or servers, it's unmatched in performance and integration simplicity. The compile-time safety of Go combined with esbuild's speed makes it ideal for build tools, but expect to write more glue code compared to higher-level build orchestration libraries.