@faststats/sourcemap-uploader-plugin

[!IMPORTANT] This package is in early development and not intended for production use. It is only published for internal testing.

Unplugin-based sourcemap uploader that works across all unplugin adapters:

• Vite
• Rollup
• Rolldown
• Webpack
• Rspack
• esbuild
• Unloader
• Farm
• Bun

What it does

• injects build metadata into entry chunks at globalThis.__SOURCEMAPS_BUILD__ (esbuild injects it into every output file)
• uploads generated sourcemaps to a backend endpoint
• uses a custom buildId, the commit hash from CI or git, or a random ID
• optionally deletes sourcemap files after successful upload

Usage

Create an API key under Project settings → Sourcemaps and pass it to the plugin:

import sourcemapsPlugin from "@faststats/sourcemap-uploader-plugin/vite";

export default {
  build: { sourcemap: true },
  plugins: [
    sourcemapsPlugin({
      authToken: process.env.FASTSTATS_SOURCEMAP_KEY,
      deleteAfterUpload: true,
    }),
  ],
};

Every bundler has its own entry point: /vite, /rollup, /rolldown, /webpack, /rspack, /esbuild, /unloader, /farm and /bun.

Options

• authToken: FastStats API key scoped to one project with the sourceMap:upload permission
• endpoint: upload URL, https://sourcemaps.faststats.dev/v0/upload by default
• enabled: true by default; set false or pass (framework) => boolean to disable the plugin conditionally
• buildId: custom build identifier; defaults to the commit hash from CI or git
• maxUploadBodyBytes: largest request body the plugin sends, 50 MB by default; builds are split into requests of about 8 MB (or this limit, if lower) that upload four at a time
• failOnError: true by default; set false to let the build succeed when the upload fails
• deleteAfterUpload: remove sourcemap files after successful upload
• globalKey: runtime global key for build metadata
• fetchImpl: custom fetch implementation
• onUploadSuccess: callback after each uploaded request; requests complete in any order
• onUploadError: callback when upload fails

Upload payload

The plugin sends POST /v0/upload with this JSON body:

{
  "type": "javascript",
  "buildId": "build-123",
  "uploadedAt": "2026-04-01T12:00:00.000Z",
  "files": [
    {
      "fileName": "assets/app.js.map",
      "content": "{...}"
    }
  ]
}

Tests

bun run test