sovereign_browser

A Linux x86 web browser built in C99 on WebKitGTK, designed around sovereign identity instead of the traditional web's permissioned infrastructure.

The thesis: the browser's security model (DNS/domains, TLS/CAs, same-origin policy, CORS, cookie sandboxing) is what forces you to rely on permissioned domains, certificate authorities, and centralized account systems. By deprecating that model and replacing it with Nostr identity and FIPS mesh transport, you get a browser that's more capable, not less safe — because trust moves to the layer where it belongs: your keys.

"Not your keys, not your browser." Walk up to a computer with your Nostr identity (via n_signer) and the browser is yours — your identity, your relays, your mesh.

Goals

1. A real browser. Loads any normal HTTP/HTTPS page via WebKitGTK.
2. FIPS addresses are first-class. http://<npub>.fips/ and fips:// resolve over the FIPS mesh, not DNS/IP. Reach any FIPS node by its Nostr npub, no domain, no public IP, no TLS cert.
3. Built-in Nostr signing. The browser injects window.nostr (the nos2x surface) into every page, backed by n_signer — a foreground, RAM-only, human-attended signing program. The browser never holds your private key; every signature is approved at the signer's terminal.
4. Deprecated web security, deliberately. Same-origin policy, CORS, and certificate enforcement are stripped so pages (and the agent runtime to come) can freely call any endpoint — including FIPS mesh services — without the workarounds traditional browsers force on automators. Security moves up to the Qube level (isolation per VM), so the browser doesn't need the traditional in-browser security model.
5. Local file browsing. Open and operate multipage websites directly from file:// with no web server — cross-origin access between local files, fetch()/XHR, iframes, storage, media playback, all work. See Local file browsing below.

Nostr interaction policy

sovereign_browser interacts with Nostr via discrete events only — no continuous WebSocket subscriptions. The browser fetches events on demand (via relay_fetch.c) and publishes events on demand (via settings_sync.c, agent_conversations.c, agent_skills.c). There is no persistent subscription that receives live updates.

This is a deliberate architectural choice:

• Simplicity — No subscription lifecycle management, no reconnection logic, no event deduplication across reconnects.
• Predictability — The user controls when data is fetched or published. No background traffic, no surprise events arriving.
• Resource efficiency — No open WebSocket connections consuming memory and bandwidth while idle.

Trade-off: The browser does not receive live updates. If a conversation or skill is created in another app (e.g., the client web app), it won't appear in sovereign_browser until the user explicitly refreshes. UIs that need fresh data provide Refresh buttons that trigger a one-shot fetch.

What this means for the chat page

The sovereign://agents/chat page differs from ~/lt/client/www/ai.html in this respect:

• ai.html uses NDK with persistent subscriptions — conversations and skills appear live as they're published to relays.
• sovereign_browser fetches conversations and skills on demand — the user clicks a Refresh button to pull new data from relays.

Conversations and skills are still stored as the same Nostr event kinds (30078 for conversations, 31123 for skills) with the same tags, so they're compatible across projects — just not live-synced.

Current status

Working browser with a broad feature set:

• Multi-tab browsing with session restore, tab drag/reorder, context menus
• Nostr login (GTK dialog or CLI flags) with multiple methods: generate, local (nsec), seed (BIP-39), readonly (npub), NIP-46, n_signer hardware
• window.nostr injection (NIP-07) into every page
• Agent MCP server — 100 tools for browser automation via Streamable HTTP at http://localhost:17777/mcp
• Local file browsing — open and operate multipage websites directly from file:// with no web server (see below)
• Bookmarks, history, search — built-in bookmark manager, browsing history, and search engine integration
• Keyboard shortcuts — standard browser shortcuts (Ctrl+T, Ctrl+W, Ctrl+L, Ctrl+Tab, etc.)
• Per-user profiles — separate identities and settings per profile
• Embedded web content — sovereign:// pages for settings, bookmarks, profile, and agent chat/config

See docs/webkit-poc-findings.md for the friction report from the POC phase.

Install

One-command install on Debian 13 (trixie) or similar (x86_64, WebKitGTK 4.1):

curl -fsSL https://git.laantungir.net/laantungir/sovereign_browser/raw/branch/master/install.sh | bash

This downloads and runs install.sh, which:

1. Installs runtime dependencies via apt (WebKitGTK 4.1, libsoup, curl, etc.)
2. Installs Tor via apt (used for .onion routing)
3. Builds and installs FIPS from source with CAP_NET_ADMIN (used for .fips mesh routing)
4. Downloads the latest prebuilt sovereign_browser binary from the Gitea releases (falls back to a source build if no binary is available)
5. Installs a sovereign-browser wrapper command to /usr/local/bin

After install, start the browser with:

sovereign-browser start --login-method generate

Install options

# Non-root install to a user-writable prefix
curl -fsSL <url> | INSTALL_PREFIX=$HOME/.local bash -s -- --yes

# Force a source build instead of downloading the prebuilt binary
curl -fsSL <url> | bash -s -- --build-from-source

# Review the script before running it
curl -fsSL <url> -o install.sh
less install.sh
bash install.sh

Run bash install.sh --help for the full option list.

What the install requires

Requirement	Why
Debian 13+ / Ubuntu 24.04+ (WebKitGTK 4.1)	The browser is dynamically linked against libwebkit2gtk-4.1
x86_64	Prebuilt binary is x86-64; arm64 needs --build-from-source
sudo / root	For apt install, setcap on the FIPS binary, and writing to /usr/local
Internet access	To download the binary, apt packages, and the FIPS source

Tor and FIPS are installed by default (not optional). If either is absent at runtime the browser degrades gracefully — clearnet still works, .onion/.fips show an error page — but the installer sets them up so everything works out of the box.

---

Build

Requires Debian 13 (trixie) or similar with WebKitGTK 4.1 dev headers:

sudo apt install libwebkit2gtk-4.1-dev
make
./browser.sh start [url]    # build + launch (detached, won't hang terminal)

Note: Always use ./browser.sh to start/stop the browser. Running ./sovereign_browser directly will hang the terminal because the GUI process keeps stdout/stderr open. See ./browser.sh --help or .roo/agents.md for details.

Command-line flags

Run ./sovereign_browser --help for the full list. Flags are parsed before GTK init, so they don't conflict with GTK's own options. Flags override ~/.sovereign_browser/settings.conf for the current run only (nothing is written to disk).

Browser / Startup

Flag	Description
[URL...] / --url <url>	Open URL(s) in tabs at startup (repeatable)
--new-tab-url <url>	Override the default new-tab URL
--no-session-restore	Skip session restore for this run
--session-restore	Force session restore even if disabled
--max-tabs <n>	Override max simultaneous tabs
-V, --version	Print version and exit
-h, --help	Show help and exit

Agent Server

Flag	Description
--port <port>	Override agent MCP server port (default 17777)
--no-agent	Disable the agent server for this run
--agent	Force-enable the agent server
--agent-origin <origin>	Allowed origin (repeatable)

Login (skips the GTK login dialog)

Specify --login-method to bypass the interactive login dialog. The method string matches the MCP login tool. Method-specific flags provide credentials.

Flag	Description
--login-method <m>	generate|local|seed|readonly|nip46|nsigner
--nsec <nsec1...>	(local) nsec bech32 private key
--privkey <hex>	(local) 64-char hex private key
--mnemonic <words>	(seed) BIP-39 mnemonic, quoted
--account <n>	(seed) BIP-44 account index (default 0)
--npub <npub1...>	(readonly) npub bech32 public key
--pubkey <hex>	(readonly) 64-char hex pubkey
--bunker <url>	(nip46) bunker:// URL
--nsigner-transport <t>	(nsigner) serial|unix|tcp|qrexec
--nsigner-device <path>	(nsigner) device path / socket / host:port / qube
--nsigner-service <name>	(nsigner) qrexec service name
--nsigner-index <n>	(nsigner) key index (default 0)
--no-save-identity	Do not persist identity to disk
--login-timeout <ms>	Override agent login timeout (GTK dialog path)

Diagnostics

Flag	Description
-v, --verbose	Increase log verbosity (repeatable)
-q, --quiet	Suppress non-error log output

Examples

# Basic usage (via browser.sh — recommended)
./browser.sh start https://example.com

# Generate a fresh key, skip the login dialog, open a page
./browser.sh start --login-method generate --url https://example.com

# Local key from env, custom agent port
./browser.sh start --login-method local --nsec "$NSEC" --port 18888

# Read-only (npub), no agent server, two tabs
./browser.sh start --login-method readonly --npub npub1... \
    --no-agent --url https://a.com --url https://b.com

# Open a local website (no web server needed)
./browser.sh start --login-method generate \
    --url "file:///path/to/website/index.html"

Architecture (summary)

┌─────────────────────────────────────────────────────┐
│ sovereign_browser host (C99)                        │
│  ┌─────────┐  ┌──────────┐  ┌────────────────────┐  │
│  │ UI /    │  │ Request  │  │ Nostr signer shim  │  │
│  │ tabs    │  │ router   │  │ (nostr_core_lib →  │  │
│  │ URL bar │  │          │  │  n_signer socket)  │  │
│  └─────────┘  └────┬─────┘  └─────────┬──────────┘  │
│                    │                   │             │
│         ┌──────────┼───────────┬───────┘             │
│         ▼          ▼           ▼                     │
│   http/https    fips://     nostr://                 │
│   (WebKit net)  (FIPS TUN)  (relays)                 │
└─────────────────────────────────────────────────────┘
                    │
                    ▼
┌─────────────────────────────────────────────────────┐
│ WebKitGTK (system lib, ~35 MB)                      │
│  WebCore renderer + JavaScriptCore + libsoup net    │
└─────────────────────────────────────────────────────┘

Full architecture, engine comparison, and roadmap in docs/architecture.md.

Custom URI scheme layer

The browser registers custom URI schemes via webkit_web_context_register_uri_scheme(). This is the network/content layer — it controls what bytes get loaded into the web view. One infrastructure, multiple uses:

Scheme	Purpose	Status
sovereign://nostr/*	window.nostr bridge — web pages call fetch('sovereign://nostr/signEvent') to sign via the C-side nostr_signer_t	✅ Working
sovereign://settings, sovereign://bookmarks, sovereign://profile	Browser-internal pages (like chrome://settings)	✅ Working
sovereign://agents/chat, sovereign://agents/config	Agent chat and configuration pages	✅ Working
fips:// / *.fips	Route to FIPS mesh nodes via TUN interface	Planned
nostr://	Fetch Nostr events from relays, render as HTML	Planned

A WebKitWebExtension (separate .so loaded into the web process) will be added later for the script manipulation layer — security stripping (CORS/SOP removal), synchronous NIP-07 calls, and content injection. The URI scheme and WebExtension serve different layers and will coexist. See plans/nostr-login-integration.md for the full decision rationale.

Nostr login

Login is a native GTK dialog (not a web page) that calls nostr_core_lib directly. Supported methods:

Method	nostr_core_lib API
Local key (nsec)	nostr_signer_local(), nostr_decode_nsec()
Seed phrase (BIP-39)	nostr_derive_keys_from_mnemonic()
Read-only (npub)	nostr_decode_npub()
NIP-46 remote signer	nostr_nip46_client_session_init()
n_signer hardware	nostr_signer_nsigner_serial/unix/tcp/qrexec() + nostr_signer_nsigner_set_nostr_index()

See plans/nostr-login-integration.md for the full implementation plan.

Browser tabs

The browser supports multiple tabs via a GtkNotebook. Each tab has its own toolbar (hamburger menu + URL entry) and WebKitWebView. All tabs share a single WebKitWebContext, so the sovereign:// Nostr bridge, security settings, and TLS policy apply to every tab automatically.

Tab features:

• New tab: Ctrl+T or the + button at the end of the tab strip
• Close tab: Ctrl+W, per-tab close button, or middle-click on the tab label
• Switch tabs: Ctrl+Tab / Ctrl+Shift+Tab, Ctrl+PageUp / Ctrl+PageDown
• Focus URL bar: Ctrl+L
• Right-click tab context menu: New Tab, Close Tab, Close Other Tabs, Close Tabs to the Right, Duplicate Tab, Reload Tab
• Drag tabs to reorder
• Tab titles update from page load
• Session save/restore: open tabs are saved on exit and restored on next launch (configurable in Settings)

Settings dialog (hamburger menu → Settings…):

• Restore session on startup (default: on)
• New tab URL (default: https://example.com)
• Tab bar position: Top / Bottom / Left / Right (default: Top)
• Show tab close buttons (default: on)
• Middle-click to close tab (default: on)
• Ctrl+Tab to switch tabs (default: on)
• Maximum tabs (default: 50)
• Allow drag to reorder tabs (default: on)

Settings are persisted to ~/.sovereign_browser/settings.conf. Session state is saved to ~/.sovereign_browser/session.txt.

See plans/browser-tabs.md for the full implementation plan.

Local file browsing

sovereign_browser is designed to run websites directly from local files — open an index.html from its directory and navigate as if it were served over HTTP. No web server required. This is a deliberate design choice: security is moved up to the Qube level, so the browser doesn't need the traditional security restrictions (same-origin policy, CORS) that would block local-file web apps.

What works on file:// pages:

• Relative links between pages — index.html → about.html, subdir/page.html, ../index.html, ../../../deep/page.html
• Cross-origin access — all file:// URLs are treated as same-origin. Iframes can access their parent's DOM, window.open() popups are accessible, and fetch()/XHR work across directories.
• fetch() and XMLHttpRequest — load local JSON, text, and other files via relative paths (returns status=0, the file:// convention)
• External resources — CSS stylesheets, JavaScript files, SVG images, favicons, <picture>/srcset, <object>/<embed>
• Video and audio playback — MP4 video and M4A audio play correctly with full duration/dimension metadata
• All browser storage — localStorage, sessionStorage, cookies, and IndexedDB all work fully (open, upgrade, put, get, count)
• history.pushState/replaceState — SPA-style routing works on file:// URLs
• Query strings and hash fragments — preserved in location.href, accessible via location.search/location.hash
• URL-encoded filenames — encoded%20name.html (file on disk: encoded name.html) loads correctly
• Form submissions — GET forms append query strings to the target page; POST forms navigate (body silently dropped, no server)
• window.open() — opens local pages in new tabs
• ES Modules — dynamic import() works with local module files
• Web Workers and Shared Workers — new Worker() and new SharedWorker() with local scripts enable background computation threads (including cross-tab shared workers)
• WebAssembly — WebAssembly.instantiate() works for compiled code
• Cross-origin fetch to remote HTTPS — fetch('https://example.com') from a file:// page works with no CORS blocking (confirms the "deprecated web security" design goal)
• Cross-origin remote resources — remote <script src>, <link rel=stylesheet>, and <img> from HTTPS CDNs all load correctly

Known limitations (WebKit engine quirks, not bugs):

• fetch() for missing files throws Load failed instead of returning an error Response (no HTTP status codes on file://)
• <video>/<audio> error events don't fire for missing source files (valid media works perfectly)
• Cache API (CacheStorage) rejects non-HTTP/HTTPS URLs — use IndexedDB instead for local-file storage
• Service Workers don't work on file:// (W3C spec requires HTTP/HTTPS) — use Web Workers for background processing instead

Test site: A comprehensive multipage test website with 53 edge cases is in tests/local-site/. See tests/local-site/LOCAL-FILE-BROWSING-REPORT.md for the full test report.

# Open a local website
./browser.sh start --login-method generate \
  --url "file:///path/to/your/website/index.html"

Agent tools (MCP server)

The browser embeds an MCP (Model Context Protocol) server using Streamable HTTP transport. External AI agents can control the browser programmatically via http://localhost:17777/mcp.

The server starts before the login dialog and remains available throughout the browser's lifecycle. An agent can log in at any time: while the dialog is showing, or after the browser is already running.

100 tools available, including:

• Login: login_status, login, logout, switch_identity
• Navigation: open, back, forward, reload, get_url, get_title
• Snapshot & inspection: snapshot, get_text, get_html, get_attr, eval, screenshot, screenshot_annotated
• Interaction: click, dblclick, fill, type, press, scroll, hover, focus, select, check, uncheck, drag
• Find elements: find_role, find_text, find_label, find_placeholder, find_alt, find_title, find_testid
• Tabs: tab_list, tab_new, tab_switch, tab_close, close, close_all
• Wait: wait, wait_for, wait_for_text, wait_for_url, wait_for_load
• Cookies & storage: cookies_get/set/clear, storage_local_*, storage_session_*
• Frames: frame_switch, frame_main
• Dialogs: dialog_accept, dialog_dismiss, dialog_status
• Debug: console, errors, highlight
• Files: upload, pdf

Example workflow:

# 1. Login (or use --login-method on the command line)
curl -s -X POST http://localhost:17777/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"login","arguments":{"method":"generate"}}}'

# 2. Open a page
curl -s -X POST http://localhost:17777/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"open","arguments":{"url":"https://example.com"}}}'

# 3. Snapshot — get accessibility tree with element refs
curl -s -X POST http://localhost:17777/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"snapshot","arguments":{}}}'

# 4. Click by ref
curl -s -X POST http://localhost:17777/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"click","arguments":{"ref":"@e2"}}}'

See .roo/agents.md for the full tool list and workflow guide, and plans/agent-tools.md for the implementation plan.

Roadmap

1. ✅ Base browser (WebKitGTK + C99, loads pages)
2. ✅ Browser tabs (GtkNotebook, per-tab toolbar, session restore, settings)
3. ✅ Nostr login (GTK dialog → nostr_core_lib → nostr_signer_t, 6 methods)
4. ✅ window.nostr injection (sovereign:// URI scheme bridge)
5. ✅ Agent MCP server (100 tools, Streamable HTTP at http://localhost:17777/mcp)
6. ✅ Embedded web content (sovereign://settings, bookmarks, profile, agents/chat, agents/config)
7. ✅ Bookmarks, history, search, keyboard shortcuts, per-user profiles
8. ✅ Local file browsing (multipage websites from file:// with no web server)
9. ⏳ Security strip (disable SOP/CORS, accept any cert, shared context)
10. ⏳ FIPS URI scheme (fips:// / *.fips via WebKitGTK scheme handler)
11. ⏳ nostr:// content scheme
12. Future: agent runtime (didactyl hosting), multi-window, FIPS-distributed

License

MIT (to match nostr_core_lib / n_signer / didactyl).