# jimmywarting/StreamSaver.js

StreamSaver writes stream to the filesystem directly asynchronous

Repository: https://github.com/jimmywarting/StreamSaver.js
Canonical: https://ross.abutalabs.com/products/streamsaverjs
Homepage: https://jimmywarting.github.io/StreamSaver.js/example.html
Language: JavaScript
License: MIT
License Family: permissive
Topics: stream, service-worker, filesaver, ram, html5
Last push: 2026-07-30T12:07:39+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 95, release rhythm 8, longevity 100
- inputs: {"age_days": 3746, "days_push": 34, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4367, forks 443 (observed 2026-08-28T04:08:46.684359+00:00)

## What it is
StreamSaver.js is a JavaScript library that lets browser apps write a WritableStream directly to the user's file system, saving large files without buffering them in RAM. It works by emulating server download headers via a service worker, making it ideal for streaming client-generated data to disk.

## Use cases
- save large files in the browser without running out of memory
- stream generated data directly to a file on disk
- download client-generated content as a file
- write a readable stream to the filesystem asynchronously
- save big exports from a web app on devices with limited RAM

## When to choose
- you need to save large or streamed data to disk in the browser without loading it all into memory
- the content is generated client-side and can't be served with download headers from a server
- you need broad browser support for streaming file saves today

## When to avoid
- the file already lives on a server - use proper Content-Disposition response headers instead
- you only need to save small blobs - FileSaver.js is simpler
- your target browsers support the native File System Access API and you don't need legacy coverage

## Facets
- artifact type: library
- maturity: maintenance
- function: file-system, streaming, file-upload
- domain: web-development, frontend, files
- platform: browser
- tags: streams, service-worker, filesaver, large-files, client-side, web-server

## Member repositories
- jimmywarting/StreamSaver.js (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:46.684359+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:21:24.333729+00:00, confidence not recorded.
  - readme: https://github.com/jimmywarting/StreamSaver.js (fetched 2026-08-28T04:08:46.684359+00:00, sha 954af71a7d0a)
  - homepage: https://jimmywarting.github.io/StreamSaver.js/example.html (fetched 2026-08-29T09:10:02.446741+00:00, sha 19c26ea04c42)
- Data as of 2026-08-30T08:39:29.467469+00:00.