Once you start delegating work to AI coding agents, you spend more time reading code than writing it. px0 is a read-only code viewer built for exactly that reading step. It runs as a single static binary, boots in under 1 millisecond, and idles at around 20MB of memory. You open it in your browser to jump to symbol definitions or check git diffs. It is developed by Arpit Bhayani in India, and v0.1.0 was published on September 13, 2026 under the MIT license.
Key Features
- Boots in under a millisecond: It uses neither Electron nor Node.js, shipping HTML, CSS, and JavaScript inside a single binary. Idle resident memory is about 20MB, so it does not get in the way even with your usual editor still open
- Fuzzy search that finishes in milliseconds: It supports search by file name, symbol, and regular expression. The official site shows an example of searching 95,710 files in the Linux kernel in 6 milliseconds
- Jump to definition via LSP: It lazily launches language servers such as gopls, rust-analyzer, and typescript-language-server from your
$PATH, enabling jump to definition, find references, and hover information. When no language server is present, it falls back to a regex-based outline view - Git diffs right where you are: It offers working-tree status badges, a filter that narrows the tree to changed files only, and a diff view against HEAD that toggles between split and unified layouts
- Markdown preview and 14 themes: It renders GitHub Flavored Markdown in place and lets you toggle between source and preview with a keystroke. Fourteen built-in themes including Tokyo Night, Dracula, and Catppuccin ship with it, and syntax highlighting covers roughly 280 languages
- Remote-first by design: You can run it on a remote server, VM, or CI runner and browse over HTTP. The official site describes the division of labor plainly ─ editing itself is left to coding agents such as Claude, Gemini, and Cursor
Pricing
| Plan | Price | Highlights |
|---|---|---|
| Open source (MIT) | $0 | All features available. No paid tier or in-product billing |
Pricing is current as of September 2026. px0 is released under the MIT license and the official site has no pricing page. Please check the official site for the latest information.
Pros & Cons
✅ Pros
- Startup latency is effectively zero, so you can open it casually when you just want to glance at some code
- Resident memory stays around 20MB, so your machine does not slow down with your editor, browser, and agents all still running
- No configuration file is required ─ point it at the directory you want to read and start it
- Run it on a remote server and forward a port, and you can read the code in a browser without pulling it down locally, skipping the work of setting up an editor over SSH
- Being a single binary under the MIT license keeps the cost of handing it to teammates or dropping it into a CI environment low
⚠️ Cons
- Because it is read-only, you cannot fix what you notice on the spot. Corrections mean going back to a separate editor or to an agent
- To use LSP features such as jump to definition, you need to install the language server for each language yourself
- As of September 2026 the version is v0.1.6. It was released recently, so its track record for long-term stability is still being built
- By default it binds only to localhost (127.0.0.1). Sharing it with a team requires additional settings such as specifying a host
Comparison with Similar Services
| Service | Main use | Difference from px0 |
|---|---|---|
| px0 | Reading and reviewing code | Read-only. Fast to start and small in resident memory |
| VS Code (Web / Server) | Full IDE including editing | Editing, debugging, and extensions are all there, but resident resource use is large |
| GitHub Codespaces / code-server | Building a remote dev environment | Provisions a whole development environment in the cloud, but setup and resource use are heavier |
Terminal tools such as bat and delta serve a similar purpose, but they do not offer LSP integration or a browser-based diff UI. It helps to think of px0 as filling the gap between the lightness of a terminal and the readability of a browser.
Who Is It For
- People who delegate implementation to AI coding agents and spend a long time reviewing the generated diffs
- People who want to read monorepos or open source codebases of tens of thousands of files on a laptop
- People who want to check code on a remote server in a browser, without configuring an editor over SSH
- People who want to add one lightweight “read-only” viewer while keeping their usual editor as is
- People who like small tools written in Go and want to inspect MIT-licensed source themselves
Summary
The time we spend reading agent-written code will only grow from here. px0 extracts that reading step alone and makes it extremely light. In exchange for dropping editing features, it gains fast startup and a small memory footprint. A realistic way to use it is to leave editing to the editor and agents you already know, and keep px0 open as a second window for review. It is open source and ships as a single binary, so the easiest first step is to launch it locally and feel the speed for yourself.