Nordstjernen Web Browser
Nordstjernen is a web browser, written from scratch in C, focused on supporting the HTML and CSS standards. It runs on Windows, macOS and Linux, with builds for Android, iOS, FreeBSD, NetBSD and the JVM. Nordstjernen is built in Norway.
Nordstjernen Browser version 1.0.20 released! The source-available flagship — more platforms, and video playback. Read the announcement · More info here.
Northstar Browser version 1.0.3 released! The GPL-licensed, more minimalist sibling. Read the announcement · More info here.
HTML Standard. Behaviour is measured against the spec text, section by section, not against another browser — 140 spec rows fully implemented, 31 partial and 0 absent across WHATWG HTML sections 1–16 (July 2026). No element or API row is fully absent any more: every one is implemented, partial, or a deliberate non-goal. Against the Web Platform Tests, the full wpt-fast tree now passes 88.4% of subtests overall — 91.7% of the HTML suite — and QuickJS runs the test262 conformance suite clean. See docs/HTML-compatibility.md.
Secure. Process-per-tab design — each tab runs in its own sandboxed renderer process (seccomp + Landlock on Linux), talking to the UI over IPC and shared-memory framebuffers · no JIT.
Minimalism. The whole engine is about 145,000 lines of clean-room C, excluding the vendored libraries — small enough for one person to read and audit end-to-end.
Capable. JavaScript on QuickJS with Canvas 2D, WebCrypto, Service Workers and the Navigation API · WebAssembly via WAMR · WebGL 1 & 2, enabled by default since 1.0.20 · inline <video> (MPEG-1 always, WebM/VP9 where FFmpeg is present) with WebVTT captions · presentation MathML · on-device safe browsing against a local blocklist.
Local AI. The about:start new-tab page is a chat with a small language model running entirely on your machine via llama.cpp — no cloud, no network at inference time. Build with -Dai=disabled for a fully offline binary.
Nordstjernen has no JIT so it is much more secure, and can still be fast enough. It ships no telemetry of any kind.
the Northstar browser
Northstar is the free-software sibling of Nordstjernen: a single-window, single-page, single-process desktop browser built from the same clean-room C engine, licensed under the GNU GPL, version 3 or later. It keeps the standards-first engine — lexbor, quickjs-ng (no JIT), WAMR, Wuffs — in about 142,000 lines of original C, and adds WebExtensions support, while leaving out multi-window browsing, per-tab renderer processes and video decoding. It runs on Linux, macOS and Windows, behind a Landlock filesystem sandbox and a default-deny seccomp filter on Linux. See the comparison table below for how the two browsers differ.
Read more about the innovations in the Nordstjernen web browser.
news
- · Nordstjernen 1.0.20 released — WebGL on by default, a blinking caret, site-compatibility and memory-safety work. Announcement » · Release notes »
- · Northstar 1.0.3 released — the GPL-licensed single-process edition: Media Queries Level 4, CSSOM used values, and use-after-free fixes. Announcement » · Release notes »
- · Nordstjernen 1.0.19 released — a big step in web-standards conformance, a new animated about:start splash, and a fresh iOS port. Announcement » · Release notes »
- · Nordstjernen 1.0.18 released — a maintenance release. Announcement » · Release notes »
- · Nordstjernen 1.0.17 released — a maintenance release. Announcement » · Release notes »
- · Nordstjernen 1.0.16 released — a maintenance release. Announcement » · Release notes »
- · Nordstjernen 1.0.15 released — a maintenance release. Announcement » · Release notes »
- · Nordstjernen 1.0.14 released — a maintenance release. Announcement » · Release notes »
- · Nordstjernen 1.0.12 released — a maintenance release. Release notes »
- · Nordstjernen 1.0.11 released — a maintenance release. Announcement » · Release notes »
- · Nordstjernen 1.0.0 released — the first stable release. Announcement » · Release notes »
specifications
Two browsers, one clean-room engine. Nordstjernen is the flagship multi-tab browser; Northstar is the GPL-licensed single-window, single-process edition.
Swipe the table sideways to see both browsers.
| Nordstjernen 1.0.20 | Northstar 1.0.3 | |
|---|---|---|
| version | 1.0.20 — released 22 July 2026 · announcement | 1.0.3 — released 22 July 2026 · announcement |
| character | flagship browser · multi-window, multi-tab | free-software edition · single window, single page |
| language | C · ~145 kLOC clean-room · GTK 4 shell · Java/JVM binding via JNI · fully auditable | C · ~142 kLOC original · GTK 4 shell · fully auditable |
| architecture | process-per-tab — each tab in its own sandboxed renderer process, IPC + shared-memory framebuffers | single process — all rendering in one compact, auditable process |
| html / css | lexbor (parser, WHATWG URL, selectors) | lexbor v3.0.0 (parser, WHATWG URL, selectors) |
| javascript | quickjs-ng — bytecode interpreter, no JIT · experimental V8 backend | quickjs-ng v0.15.1 — bytecode interpreter, no JIT |
| webassembly | WAMR — interpreter behind the WebAssembly JS API |
WAMR (vendored subset) — interpreter |
| webgl | WebGL 1 & 2 — enabled by default since 1.0.20 | — |
| images | Wuffs v0.4 (PNG / GIF / BMP / JPEG) · libwebp (WebP) · libavif (AVIF, optional) · SVG via librsvg | Wuffs v0.4 (PNG / GIF / BMP / JPEG) · AVIF · SVG via librsvg |
| media | inline <video> — MPEG-1 via pl_mpeg · WebM (VP9/VP8 + Opus/Vorbis) via optional FFmpeg · WebVTT captions · SDL2 audio |
audio only — MP3, MP2, Ogg Opus/Vorbis, audio MSE streams · <video> lays out but does not decode |
| extensions | — | WebExtensions — local extensions with content scripts, packaged resources, storage and runtime messaging |
| ai | llama.cpp — on-device AI chat · no cloud · optional GPU offload (Vulkan / Metal) · -Dai=disabled for offline builds |
— |
| ui | GTK 4 (≥ 4.22.1 on Windows, ≥ 4.14 elsewhere) · Pango text shaping | GTK 4 (≥ 4.14) · Pango text shaping |
| network | libcurl ≥ 8.5 · HTTP/2 · nghttp2 on Windows since 1.0.20 | libcurl ≥ 8.5 · HTTP/2 · HTTP/3 when the linked libcurl provides it |
| hardening | process-per-tab · seccomp + Landlock sandbox on Linux · sandboxed renderer processes · no JIT | Landlock filesystem sandbox + PR_SET_NO_NEW_PRIVS · default-deny seccomp filter on Linux · no JIT |
| privacy | no telemetry · partitioned cookies · HSTS · CSP · SRI · on-device safe browsing | no telemetry · HSTS · CSP · SRI · safe browsing via local blocklist |
| standards | 140 spec rows fully implemented, 31 partial, 0 absent · WHATWG HTML sections 1–16 · Web Platform Tests: 88.4% of subtests overall, 91.7% HTML (July 2026) | same engine lineage · behaviour measured against the spec text, section by section |
| platforms | linux (gtk) · windows · macos · android · ios · java/jvm · freebsd · netbsd | linux · macos · windows |
| license | NSL-1.0 → MIT after 10 years · The Nordstjernen Source License is inspired by the Functional Source License (FSL), a Fair Source license that converts to Apache 2.0 or MIT. | GNU GPL v3 or later — free software |
| source | github.com/nordstjernen-web/nordstjernen | github.com/nordstjernen-web/northstar-browser |
download
Latest tagged release: Nordstjernen 1.0.20 — released 22 July 2026. Builds for Windows, macOS and Linux, plus the source, are all on the download page. Android is available on Google Play.
Northstar 1.0.3 — released 22 July 2026 — is on GitHub, with a Windows build and the GPL source.
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