Netlify configuration

Config lives in three files at the repo root (or the base/package directory for monorepos):

• netlify.toml — build, contexts, plugins, functions, redirects, headers, dev.
• _redirects — plain-text redirect/rewrite rules, saved to the publish directory, no extension.
• _headers — plain-text response headers, saved to the publish directory.

netlify.toml values take precedence over the Netlify UI when they conflict. Paths in netlify.toml are absolute relative to the base directory (root / by default).

Modern vs legacy syntax to reach for

• Functions bundler: use node_bundler = "esbuild". zisi is the legacy JS default; TypeScript always uses esbuild.
• Temporary redirect: use status = 302. 307 is unsupported.
• Gatsby Image CDN: use NETLIFY_IMAGE_CDN, not the deprecated GATSBY_CLOUD_IMAGE_CDN.
• Injecting env values into TOML: key = "$VAR" is NOT supported (except signed in proxy redirects). Use a build-command sed substitution or a build plugin (see below).

netlify.toml build + contexts