ANVIL

The AI code editor for quant, trading, crypto, ML and data work.

Monaco + language servers + terminals + git, rebuilt around Python research workflows: run # %% cells in a live IPython REPL, open Parquet in a real data grid, edit code with AI in place, and never commit an API key or a seed phrase again.

Download for Windows · Architecture · Decisions

General-purpose editors treat a backtest like any other script. Anvil is tuned for the loop you actually live in: tweak a signal, run the cell, look at the numbers, ask "is this leaking the future?", repeat. Everything else (the extension marketplace, the 300 settings) is gone. It starts fast and stays out of the way.

• Monaco with real language servers: basedpyright for Python (using your interpreter's site-packages), typescript-language-server for TS/JS. Go to definition, hovers, inlay hints and diagnostics.
• Split editors, preview tabs, breadcrumbs that show the class › method and the # %% cell you're in.
• Git in the gutter: added / changed / deleted bars against HEAD, plus inline blame for the current line.
• Local history: every save is snapshotted (50 per file, 30 days). Diff or roll back without git.
• Bookmarks, an outline with cells, classes, functions and constants, a TODO/FIXME radar, and ripgrep search.
• Quick Open (Ctrl+P) with fuzzy matching; > commands, @ symbols, : line.
• 51 snippets for quant and ML work: Sharpe, Sortino, drawdown, Kelly, Black–Scholes + greeks, implied vol, purged K-fold, triple-barrier labels, vectorised backtest, ccxt pagination, PyTorch loops, Optuna, polars/DuckDB. Type the prefix or browse the Snippets view.

• Scratchpad (Ctrl+Alt+P): a buffer that persists between sessions and never touches your project. # %% cells run in the REPL like any file.
• Transform selection (Ctrl+Alt+X): 46 transforms, previewed on your own text. Case (snake, camel, Pascal, kebab, CONSTANT, dot, Title…), lines (sort A→Z, numeric or by length, reverse, shuffle, unique, number, to a Python list), clean (trim, dedent, tabs ↔ spaces), encode/decode (base64, URL, JSON string, HTML entities, hex, unicode) and code (f-string, print() the variables, key: value lines to a dict, sort imports).
• Evaluate math (Ctrl+Alt+=): select price = 1.5k, qty = 20, price * qty * 2% and get 600 in place. Suffixes (k, m, b), percentages, variables, sqrt, ln, exp, mean, std, round and friends.
• Clipboard history (Ctrl+Alt+V): your last 30 copies from the editor, terminal and chat, searchable. Memory only, never written to disk.
• Insert (Ctrl+Alt+I): UUID, nano ID, ISO / unix timestamps, random hex, lorem ipsum.
• Code Snap (Ctrl+Alt+C): a styled PNG of the selection or file, with eight backgrounds, window chrome, line numbers, padding and font size, ready to copy or save.
• Back / forward (Alt+← / Alt+→) through the places you jumped from.
• Spotlight (Ctrl+Alt+D) dims everything except the current cell, function or paragraph.
• Error lens writes errors and warnings at the end of their line. TODO / FIXME / HACK / NOTE get their own colors. Color swatches with a picker appear next to #hex, rgb() and hsl() in any file.
• Clickable tracebacks: File "…", line 42 and src/a.py:12:5 in the terminal open the file at that line.
• Compare a file with the clipboard or with another file. Trim trailing whitespace and final newline on save. Alt+Z word wrap, change language mode, convert indentation. The status bar counts selected lines and words, and the palette lists what you ran recently first.

• Interpreter picker: finds .venv/venv, uv, conda and system Pythons. The language server, run commands and REPL all follow it.
• Run file (F5), run cell (Ctrl+Enter), run cell and advance (Shift+Enter), run selection (F9). Cells go to a persistent IPython REPL, Jupyter-style, with your variables kept between runs.
• Data viewer for CSV, TSV, JSON/JSONL, Parquet, Feather and Excel. Virtualized to a million rows, with filter, sort, cell-range copy and a column profile (nulls, unique, mean/std, histogram). Parquet and Excel are read by your own Python (polars first, then pandas).
• Notebook viewer for .ipynb (outputs, images, tracebacks), with one-click conversion to a # %% script. Plus image and Markdown previews.
• Tasks: npm scripts, pyproject scripts, poe, pytest, ruff, Makefile and justfile targets, detected and runnable in one click.
• Format on save with ruff. Project templates: quant research, ML training, paper-trading bot, FastAPI + DuckDB data API, minimal uv project.

• Chat that sees your file, selection, git diff and errors. @ attaches files, / runs commands, and code blocks can be copied, inserted, or applied through a diff preview.
• Inline edit (Ctrl+I): describe a change, watch it land in place, then accept (Tab) or reject (Esc).
• Ghost-text autocomplete from a fast model (Claude Haiku 4.5 by default). Requests are debounced and cancelled the instant you keep typing.
• One-click actions: explain, find bugs, write pytest tests, add docstrings, vectorise, fix the problems on this line, write the commit message, and audit for look-ahead bias and leakage.
• Works with Claude, OpenAI, Gemini, or a local Ollama (free, offline, fill-in-the-middle autocomplete). Claude requests use prompt caching, so follow-ups are cheap.

• Secret shield: .env values are blurred (hover to peek). API keys, PEM keys, EVM private keys, Solana keypairs and seed phrases in code are flagged as problems. Commits that stage one are blocked.
• API keys live only in the main process, encrypted with Windows DPAPI. The UI can ask whether a key exists, never for its value.
• A sandboxed renderer with a strict CSP, a typed and validated IPC contract, and no navigation away from the app.

• Toolbox: unix timestamps (s/ms/µs/ns), wei/gwei/ETH, lamports/SOL, sats/BTC, bps/%, base58/hex/base64, JWT decode, JSON format, regex tester, SHA-256, position sizing, compound growth.
• Terminals: PowerShell, cmd, Git Bash, a Python env shell, the REPL, and Claude Code / Codex / Gemini CLI presets.
• Command palette for everything, a menu bar, a keyboard shortcuts sheet, zen mode, and a status bar with git, problems, interpreter, language servers, AI status and Anvil's own CPU and memory.

A skin isn't a color theme. Each one changes the layout, chrome, fonts, icons, shapes and effects, so Anvil can look like a completely different program, and each skin has 4 to 16 color variants of its own. Ctrl+Alt+Y switches skins with a live preview as you arrow through them; Ctrl+Alt+T flips through the current skin's variants.

Inside any skin you choose the color variant, the accent (the variant's own, a preset, or any color), the interface font (each skin offers the fonts it was designed for), the code font (12 bundled: JetBrains Mono, Fira Code, Cascadia Code, Geist Mono, Monaspace Neon, Maple Mono, Victor Mono, Iosevka, IBM Plex Mono, Space Mono, Share Tech Mono, VT323), density (compact / cozy / roomy), effects (full / subtle / off: scanlines, glows, sweeps and grain calm down or disappear) and which side the side bar sits on. Plus line height, cursor style, a neon cursor, rainbow indentation and tabs tinted by file type.

Skins live in their own folders and are discovered automatically; docs/SKINS.md explains how to write one.

It's also quick. The installed app reaches an interactive workbench in about 0.4 s, and the UI process idles at about 110 MB; the rest is Electron's usual main and GPU processes. Monaco (~10 MB), the viewers and the chat panel load the first time you use them. Measure it yourself with npx tsx scripts/measure.mts.

Effects are optional. Settings → Appearance → Effects: subtle / off (and Glass for Cyber Glass) calms every skin down, for integrated GPUs and battery. The editor itself never renders over a blur, so text stays crisp and scrolling stays cheap.

Download the installer from Releases and run it. It updates itself in the background from the same page. The installer is not code-signed, so SmartScreen may ask once: choose More info → Run anyway.

Then add a key under Settings → API Keys (Anthropic, OpenAI or Gemini), or point Settings → AI → Ollama at a local server. Everything except AI works without one.

For Python features, have Python installed or a venv in your project (uv venv). IPython and ruff are used when they're available.

Windows 11, Node ≥ 22, Git.

npm install
node node_modules/electron/install.js   # Electron downloads its binary lazily
npm run dev                              # app with hot reload (F12 = devtools)

Renderer (React 19, sandboxed, no Node)       Main process (Node)                  Your machine
┌──────────────────────────────────┐         ┌─────────────────────────────┐     ┌───────────────────┐
│ Workbench · Monaco · xterm       │ typed,  │ fs · git · ripgrep · pty    │────▶│ python / IPython  │
│ Quick Open · Chat · Data grid    │◀──zod──▶│ LSP relay · AI (streaming)  │     │ basedpyright · tsls│
│ Zustand + TanStack Query         │  IPC    │ secrets (DPAPI) · updater   │────▶│ AI APIs / Ollama  │
└──────────────────────────────────┘         └─────────────────────────────┘     └───────────────────┘

Details in docs/ARCHITECTURE.md. Every non-obvious choice is written up in docs/DECISIONS.md.

Built by Marto with Claude Code.