Connect your app

1.Add the Spool SDK

Install the package and initialise it once in your application, with your Spool address, the project and its ingest key:

npm install @just-every/spool

import { init } from '@just-every/spool';
init({ endpoint: "http://127.0.0.1:8787", project: "web-app", ingestKey: 'YOUR_INGEST_KEY',
  release: "r42", build: "b1907" });

It listens for errors and unhandled promise rejections in the browser, next to anything else you already use. Add explicit labels with breadcrumb('checkout', 'payment submitted'); Spool never collects form values, requests or console output on its own, and it removes common secrets before anything leaves the page.

Browsers can only send to Spool from origins you allow: add your application's exact origin on the Capture page.

On a server, import init and captureException from @just-every/spool/node. In a Cloudflare Worker, call captureException(error, options, ctx) from @just-every/spool/worker; it keeps the Worker alive with ctx.waitUntil until Spool answers.

2.Register the release

Open Releases and add the release name and build your application reports, such as r42 and b1907. Register each release in the order you ship them: that order is how Spool knows a resolved issue has come back in a later release. Spool refuses errors from releases it does not know.

3.Upload the source maps

Upload the .map file for each bundle of that release and build in Releases. Spool keeps maps private and never fetches source files from the internet. A project holds up to 20 maps of 256 KiB each.

You can also upload maps from your build with a deploy key from Settings. A deploy key can only register releases and upload maps for its project. Keep the key in your build's environment, never in your application's source. With Vite or Rollup, add the SDK's plugin:

import { spoolSourceMaps } from '@just-every/spool/vite';
export default {
  build: { sourcemap: true },
  plugins: [spoolSourceMaps({ endpoint: 'https://spool.example', project: 'web', release: 'web@1.2.0', build: 'build-42', keyEnv: 'SPOOL_DEPLOY_KEY' })],
};

With any other bundler, run the command-line tool after the build:

npx spool-sourcemaps --endpoint https://spool.example --project web \
  --release web@1.2.0 --build build-42 --key-env SPOOL_DEPLOY_KEY dist/app.js

Each bundle needs its .map next to it. Both register the release, mark each bundle so the SDK can match its errors to the map, and upload the maps. The tool prints only how many maps it uploaded, and a failed upload fails your build.

4.Check it works

When you create a project, Send test error registers the release shown and sends one real error with the new key. The Capture page can also send a test exception with your ingest key. It appears in Issues, with its stack mapped to your original source once the matching map is uploaded.