The modern web, on a 25-year-old Mac.

MacSurf is a web browser for Classic Mac OS 9 PowerPC. CSS3, ES5 JavaScript, and PNGs with alpha — running on a G3 iMac.

MacSurf is a nights-and-weekends project. If it brought your old Mac back to the web, a coffee helps keep development going.

Intro Video

Note

Early alpha — it runs, renders, and speaks TLS 1.3 natively on a 233 MHz G3, but most of the modern web won't work in it yet. Expect hand-built pages, retro-style sites, and the strange thrill of ES5 JavaScript on PowerPC. Don't expect smooth browsing on arbitrary modern sites, video, or anything React-heavy.

If you've got a Power Mac G3 or G4 sitting around, load it up and see what breaks — bug reports and real-hardware screenshots are exactly what this project needs. See docs/status.md for the current punch list.

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Why this exists

The web outgrew Classic Mac OS twenty years ago. Modern HTTPS finished it off around 2016. Pull a G3 or G4 out of the closet today and it can barely reach a single live website.

MacSurf is an attempt to fix that on the machine itself — no screenshot proxy, no remote terminal trick. A native browser, built with the tools that were already on the platform: CodeWarrior, Carbon, QuickDraw, Open Transport. Real CSS3 layouts and real JavaScript, running inside the 64 MB memory floor of a 1999 iMac. Since late May 2026 it speaks TLS 1.2 directly to the modern web through macTLS, a BearSSL-based stack that ships inside the browser binary with 121 trust anchors from the Mozilla CA bundle. No proxy needed anymore.

As far as we can tell, this is the first serious NetSurf port to Classic Mac OS, and the first browser ever shipped on Mac OS 9 with native CSS Grid, CSS custom properties, and ES5 JavaScript.

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The progression

Each shot below is a real milestone, captured on a Power Macintosh G3 running Mac OS 9. The fix-number annotations match this repo's commit history.

v0.2: JavaScript on Mac OS 9 First real-world JS-bearing page. Duktape 2.7.0 ES5 evaluating live: Math.sqrt, JSON, ES5 array methods.	fixes73: CSS transforms Native transform: rotate() / scale() / translate(). Integer Q15 sin/cos table, no FPU dependency, arbitrary angles on QuickDraw.
fixes74d: radial gradients 2-stop radial gradients via concentric PaintOval stack. 16 levels smeared on decode. Shape + position keywords parsed.	fixes77: CSS animations Linear ping-pong animation player on top of fixes73 rotation. Wiggle, swing, and full 0°→359° spin.
fixes79b: PNG transparency QuickTime Graphics Importer feeding the NetSurf image content handler. PNG + GIF + BMP, all with real transparency.	fixes136: word-break / overflow-wrap word-break: break-all, keep-all, white-space: nowrap, legacy word-wrap: break-word. URL-style aggressive wrapping.
fixes147: stacking contexts CSS 2.1 painting order. Opacity, transforms, and explicit z-index all create new stacking contexts, properly painted on real hardware.	fixes151: CSS Grid column placement grid-column: span N, 1 / -1 full-row hero, positional start / end, span + auto-wrap. Real Grid layout on OS 9.
v1.0: Showcase The new tool-belt toolbar, razor-sharp URL field, and matted icons rendering home.macsurf.org on a G3 iMac running OS 9.2.2. Native HTTPS via macTLS direct to the origin, server-rendered portal, true-colour images end to end.

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The pieces

Component	Language	Purpose
browser/	C (C89, CW8)	NetSurf fork with a macos9 frontend. Carbon for the UI, QuickDraw for drawing, Open Transport for networking, Duktape for JS.
proxy/	Go (stdlib only)	The old TLS-stripping HTTP proxy. Largely retired now that macTLS works natively, but still useful as a fallback or on machines without CarbonLib. Mac sends plain HTTP, proxy fetches via HTTPS, returns plain HTTP.
macTLS sibling repo	C (CW8)	Native TLS 1.2 library for OS 9 — modern HTTPS straight from the Mac, no proxy required. BearSSL underneath, 121 trust anchors baked in.

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What works today

Rendering pipeline Full NetSurf fetch → parse → cascade → layout → plot Native libcss with var() resolution QuickDraw plotters with an offscreen GWorld back-buffer CSS — around 150 properties consumed in layout Custom properties and var() Flex: justify-content, align-content, order Grid V1 plus grid-template-columns/rows, gap border-radius, box-shadow, opacity Linear and radial gradients text-shadow, text-overflow: ellipsis transform (rotate, translate, scale) z-index stacking contexts (CSS 2.1 painting order) CSS counters, viewport units, aspect-ratio Font-family aliases for sans, serif, monospace Full CSS status →

JavaScript — Duktape 2.7.0, full ES5 Closures, prototypes, regex, JSON Promises (polyfill), recursion, Mandelbrot About 6 seconds for ackermann(3,7) on a 233 MHz G3 Images — all five formats PNG with real per-pixel alpha (lodepng + CopyMask) GIF with palette transparency JPEG, BMP, TIFF Networking Open Transport TCP, plain non-InContext calls HTTP/1.1 + chunked + keep-alive + 3xx follow Connection pooling, 15-second no-progress timeout HTTPS via macTLS (default) or the Go proxy (fallback) Browser chrome Address bar, back / forward / reload / home Status bar, page-info, multi-window Smooth scroll bar, keyboard scrolling

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Download

Latest is MacSurf v1.4 — Open House (2026-06-01): JavaScript marathon closed. 23 JS-bridge issues went from open to closed in one release — setTimeout / setInterval / requestAnimationFrame, window.location, window.history, URL, URLSearchParams, classList, style, Event constructors, MutationObserver, DOMParser, FormData, localStorage, fetch, load / DOMContentLoaded events, plus <details> / <summary> toggle. The new probe suite scored JS 19/19 pass, 0 fail on a G3 iMac. Diagnostic pages live: about:cache, about:memory, about:config, about:perf all render real counters. View Source renders inline, Find-in-page opens a real Carbon dialog. Predecessor v1.3.1 "Forward, refined" shipped multi-curve TLS 1.3; v1.3 "Forward" was the first native TLS 1.3 on Classic Mac OS; v1.2 "Sealed" closed the entropy hole; v1.0 "Showcase" was the chrome-redesign release; v0.6.2 "Speed-Run" was the cold-load speedup (mactrove.com 30+s → ~2-3s); first numbered alpha at v0.1a1.

• MacSurf.sit — the v1.4 binary, ready to run. Expand on Mac OS 9.1+ with CarbonLib 1.5+ and launch.
• Building from source: clone the repo, then on the Mac side open browser/netsurf/frontends/macos9/MacSurf.mcp in CodeWarrior 8 and choose Build. v1.4 builders on a v1.3.1 workspace need to add one new source file to the project: browser/netsurf/desktop/search.c (provides browser_window_search for the new Find dialog; content/textsearch.c is already in). macTLS is unchanged from v1.3.1. v1.3 builders on a v1.2 workspace need to add four macTLS files for TLS 1.3: bearssl/src/ec/ec_c25519_m15.c, os9/ostls_tls13_keysched.c, os9/ostls_tls13_record.c, os9/ostls_tls13_handshake.c. v1.2 builders on a 1.0 workspace need desktop/download.c. The earliest release ships a BuildPack.sit snapshot with the CW8 project pre-wired, but current builds work straight from a fresh clone.

Earlier alpha notes if you want context: docs/release-notes/MacSurf-0.1a1.md.

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Getting started

Building the browser MacSurf is built on Mac OS 9 with CodeWarrior 8 Pro (8.3 update). The source is cross-compile-clean against Retro68 PowerPC GCC, which is what we use for fast Linux-side syntax checks. Mac-side build guide Linux cross-dev workflow