Gatsby Postbuild

Project Overview

Gatsby plugin that adds an event-based pipeline that runs after gatsby build to transform and optimize the files in /public. It ships ready-made tasks (PurgeCSS, HTTP headers, Minify) and lets you define custom tasks that hook into file-type events (e.g., HTML AST) or generic file events.

Key Features

• Provider headers generation: emits hosting configs (e.g., Firebase firebase.json, Netlify _headers, Vercel) for resource hints (prefetch, preload, preconnect), caching, security and other critical headers.
• Built-in tasks: PurgeCSS, HTTP headers (provider presets), Minify (terser/cssnano).
• Custom tasks via events: register handlers for generic contents or HTML events like parse, tree, node, serialize, write.
• Processing controls: choose parallel or sequential strategies and set concurrency globally or per extension.
• Ignore & per-task filters: exclude files globally or per task (e.g., skip specific HTML paths for PurgeCSS).
• Reporting: optional postbuild.log.json and console summary with toggles.
• Lifecycle hooks: on.postbuild, on.shutdown, and [extension].configure for setup/teardown and per-type config.

Why it exists

• Close the “last mile”. Gatsby stops at generating /public; teams hack the rest in CI scripts. Postbuild provides a structured, repeatable stage for that work.
• Put critical headers at the edge. Generate provider configs so browsers/crawlers receive resource hints in the first response, enabling action before the page HTML is parsed.
• Make builds reproducible. Run the same tasks locally and in CI, with clear logs and one config.
• Unify common optimizations. PurgeCSS, minification, HTTP headers, redirects, and custom file transforms—all in one pipeline.

Check out the project repository on Github for more info.