Nordstjernen web browser

Nordstjernen is a web browser written from scratch in C, focused on support for modern HTML, CSS and JavaScript standards. It is built in Norway.

Desktop builds run on Windows, macOS, Linux, FreeBSD and NetBSD. The same engine also powers Android and iOS shells and a Java/JVM binding.

Current release: 1.0.28 (October 2026) — see Changelog.md.

Standards. Behaviour is measured against the spec text, section by section, not against another browser. The walk-through of the in-scope WHATWG HTML standard (§1–§16) in docs/HTML-compatibility.md records 140 spec rows fully implemented, 31 partial, 0 absent (July 2026), besides a handful that are non-goals by design: embed/object plugins, frame/frameset, applet/marquee, telemetry, and AI-style web APIs.

Security. Each tab's engine runs in its own sandboxed process (seccomp + Landlock on Linux) behind an IPC + shared-memory-framebuffer boundary. No JIT.

Minimalism. The core engine is about 210,000 lines of project C and headers, excluding vendored libraries and generated assets — small enough for one person to read and audit end-to-end.

See northstar-browser-gpl for the GPL-licensed sibling project.

Download

Windows 10 or later is required (the GTK 4 frontend links DirectComposition). Every other platform builds from source — see "Build" below and the per-platform install notes in docs/.

Browser features

• HTML/CSS — HTML is parsed by the in-tree lexbor engine; the CSS engine covers the modern cascade and CSSOM, Media Queries Level 4, container queries and units, flex, grid, transforms, gradients, animations and vertical writing modes.
• Text layout — desktop builds shape text with ns-pango, a Pango fork pinned as a meson subproject that caches finished glyph strings and font metrics across layouts, so measuring and painting a run reach HarfBuzz once instead of three times. Android and iOS link the system Pango; -Dns-pango=disabled builds that path on the desktop too.
• JavaScript on the QuickJS interpreter — DOM, Shadow DOM, observer APIs, Canvas 2D (Path2D, ImageBitmap, DOMMatrix), WebCrypto (crypto.subtle over OpenSSL), custom elements including customized built-ins (is= / {extends}), and the Navigation API for single-page routing, plus Web Workers, IndexedDB (over SQLite), WebSocket and EventSource. The engine binding is a build-time seam: an experimental V8 backend (-Djs_engine=v8, external V8 monolith, never vendored) runs page scripts with live core DOM bindings while QuickJS stays the default — see docs/V8.md. The QuickJS itself is selectable too: the in-tree quickjs-ng fork by default, or Fabrice Bellard's original QuickJS with -Dquickjs=quickjs — see docs/quickjs.md.
• Networking over HTTP/2 with libcurl — HSTS, CSP, subresource-integrity checks, partitioned cookies, speculative subresource loading, request coalescing and a Vary-aware HTTP cache. An in-tree libnghttp2 transport backend is selectable at build time (-Dhttp_backend=nghttp2), with HTTP/3 over QUIC via ngtcp2 + nghttp3 + gnutls when present. Both backends fetch byte-identically, so the independent transports cross-check each other. See docs/http-backends.md.
• Images and graphics — Wuffs decodes PNG/APNG, GIF, BMP, JPEG and lossy WebP; libwebp handles lossless and animated WebP; ICO and SVG are rendered in-engine, with optional AVIF and inline PDF support.
• Media — <video> plays inline for MPEG-1 (decoded in-tree by pl_mpeg) and, when FFmpeg's libav is present at build time, WebM (VP9/VP8 + Opus/Vorbis). MSE/blob: streaming and HLS/DASH manifests play through the nordstjernen-video helper, and a <track default> WebVTT file is drawn over the video. Other codecs render a poster and play overlay. See docs/media.md.
• WebGL / WebGPU / WebAssembly — WebGL 1/2 mapped onto OpenGL ES, on by default (docs/webgl.md); experimental navigator.gpu over external wgpu-native, built only when that library is installed and gated behind --enable-webgpu (docs/webgpu.md); the full WebAssembly JS API over a vendored WAMR interpreter (docs/webassembly.md).
• MathML — a minimalist presentation-MathML renderer (src/mathml.c) laid out over Pango/Cairo and embedded inline on the text baseline.
• Spell checking — optional, via Enchant: misspelled words in editable text get a red wavy underline, honouring the spellcheck attribute.
• Safe browsing — a top-level navigation's host is checked against a local SHA-256 blocklist before it is fetched, entirely on-device; a match shows a full-page warning. Overridable via ~/.config/nordstjernen/safebrowsing.list.
• Process-per-tab — each tab's engine runs in its own sandboxed nordstjernen-renderer process; the GTK app is a thin shell that blits the renderer's shared-memory framebuffer and forwards input over an IPC control channel, so a page can't take down the UI (docs/tab-isolation.md). --single-process runs every tab's engine in the shell process instead (docs/single-process-mode.md).
• Privacy — no telemetry or update pings, standards-compliant client hints, local-only safe browsing, partitioned cookies and a --private session mode.
• UI — tabs, bookmarks, history, downloads, find-in-page, printing and save-to-PDF, a JavaScript console, settings, headless mode, and a C embedding API (docs/Embedding.md). The interface is translated into 40 languages and follows the operating-system language (docs/i18n.md).
• Extensions — initial support for simple, page-facing WebExtensions (docs/extensions.md).
• Java/JVM — org.nordstjernen.Nordstjernen drives fetch / parse / layout / script / render from Java over a JNI bridge, or RemoteBrowser / RemotePage drive a separate renderer process so an engine crash can't take down the JVM. The fat jar is both the embedding library and a standalone Swing browser (java -jar nordstjernen-java.jar <url>). See java/README.md.

Build

sudo apt install build-essential git pkg-config meson ninja-build \
    libgtk-4-dev libepoxy-dev libcurl4-openssl-dev libssl-dev libuchardet-dev \
    libpsl-dev libsqlite3-dev libseccomp-dev libwebp-dev libsdl2-dev \
    libavformat-dev libavcodec-dev libavutil-dev libswscale-dev libswresample-dev
meson setup builddir && meson compile -C builddir
./builddir/src/gtk/nordstjernen

Windows, Fedora, openSUSE and macOS instructions are in docs/; keyboard, mouse and touch controls are in docs/Controls.md.

Dependencies

Nordstjernen is an independent engine — no upstream browser code.

Vendored in-tree, built from the main tree with no submodules: lexbor (HTML5 → DOM parser, CSS, and the WHATWG URL module), QuickJS (quickjs-ng fork, no JIT), WAMR (WebAssembly interpreter), Wuffs (memory-safe image decoding), pl_mpeg (MPEG-1 video + MP2 audio) and minimp3 (MP3). The only setup-time download is ns-pango, the text-shaping fork; -Dns-pango=disabled links the system Pango and needs no network.

Required system libraries:

Optional, auto-detected or build-time-selected: FFmpeg libav* (inline WebM playback — required on Linux and Windows, auto-detected on macOS), poppler-glib (inline PDF), libavif (AVIF images), Enchant (spell checking), fontconfig / pangoft2 (extra font backends), libnghttp2 (the in-tree HTTP/2 backend), ngtcp2 + nghttp3 + GnuTLS (HTTP/3 over QUIC inside it), wgpu-native (experimental WebGPU), a V8 monolith (experimental -Djs_engine=v8) and Fabrice Bellard's original QuickJS (-Dquickjs=quickjs, fetched through a meson wrap).

License

Nordstjernen is dual-licensed: use it under either the Nordstjernen Source License v1.0 or the GNU General Public License version 3 or later, at your option (LicenseRef-NSL-1.0 OR GPL-3.0-or-later).

• GPL-3.0-or-later — free software: use, modify and redistribute it for any purpose, provided derivative works are also released under the GPL. See COPYING.
• NSL-1.0 — use, modify and redistribute freely, except as a competing browser; each release becomes MIT after ten years. It is inspired by the Functional Source License.

See License.md for the full terms. Commercial licenses by agreement. Bundled third-party components keep their own licenses (THIRD-PARTY-LICENSES.md).

Project home: https://nordstjernen.org · Copyright 2026 Andreas Røsdal · Join the Discord

Builds