https://t.co/YPXYJCel3U is really fast.

The way I’m gonna use it is pretty simple, quickly checking files without opening the actual IDE.

Especially files like pubspec.yaml and package.json.

thanks @arpit_bhayani !! https://t.co/D90vhPzxi6

px0: a fast, lightweight, read-only IDE

Source: https://px0.ai/ px0v0.1.0read-only ide for the ai-agent erasingle static go binarymit

//agents write the code. you verify it.

When all you want isspeed.

px0 is a read-only IDE for the AI-agent era. It turns your browser into an instant verification console for whatever your agents just wrote: symbol-level navigation, full LSP intelligence, and deep search. One binary, zero config. It starts inunder 1 ms, idles at**~16 MB**, and fuzzy-finds across the Linux kernel’s95,710 files in 6 ms.

cold start<1mssub-millisecond instant bootresident memory16MBVS Code on the same tree: ~1,440 MBfuzzy find6.0mslinux kernel, 95,710 fileslanguages~280tokenized natively by Chromathemes14one CSS file eachruntime deps0no Electron, no Node, no CGO ~/src/px0 · fuzzy.go

127.0.0.1:7777

50// Collected right-to-left; flip in place.

51fori,j:=0,len(pos)-1;i<j;i,j=i+1,j-1{

52pos[i],pos[j]=pos[j],pos[i]

53}

54

55score,prev:=0,-2

56fork,i:=rangepos{

57ifi==prev+1{

58score+=12// consecutive run

59}elseifk>0{

60score-=min(i-prev,12)// gap penalty, bounded

61}

62ifi>=e.nameStart{

63score+=14// basename beats directory noise

64}

65ifi==0||isBoundary(p[i-1]){

66score+=16// start of a path or word segment

67}elseifp[i]>=‘A’&&p[i]<=‘Z’&&p[i-1]>=‘a’&&p[i-1]<=‘z’{

68score+=14// camelCase hump

69}

70ifp[i]==q[k]{

71score+=4// exact case

72}

73prev=i

74}

75// Prefer the shallower, shorter of two otherwise-equal paths.

76score-=len(p)/8

77score-=strings.Count(p,“/”)*2

78ifidx:=strings.Index(e.lower[e.nameStart:],q);idx>=0{

79score+=40// whole query appears verbatim in the basename

80ifidx==0{

81score+=20

82}

83}

84returnscore,pos,true

85}

14 themes

01/bench

Measured,not claimed.

Every number here comes from\./benchmark\.shagainst shallow clones of seven real repositories. Linux, language servers off, fastest of five requests. Run it on your machine and paste the table anywhere.

resident memory · same workspace · linear scale**~90x**lighter

VS Code15+ processes

~1,440 MB

1. 1extension host**~500 MB**
2. 2language server**~350 MB**
3. 3server main**~260 MB**
4. 4IPC proxies & utility**~190 MB**
5. 5PTY host & terminal**~71 MB**
6. 6file watcher**~68 MB**

real corpus · px0 standalonesorted by files indexed

repolangsourcefilesindexfuzzyfull scanopen bigreopenrsspeakflaskPython3 MB2351 ms0.8 ms2.3 msn/an/a16 MB18 MBredisC26 MB1,85513 ms1.0 ms18.2 ms80.8 ms1.2 ms17 MB27 MBdjangoPython74 MB7,01439 ms1.3 ms26.8 ms166.8 ms1.0 ms20 MB29 MBreactJavaScript63 MB7,17852 ms2.7 ms32.2 ms57.7 ms0.7 ms21 MB28 MBkubernetesGo370 MB25,926150 ms13.5 ms84.6 ms199.0 ms0.9 ms30 MB44 MBtypescriptTypeScript414 MB66,533566 ms6.2 ms150.3 ms40.9 ms6.5 ms69 MB105 MBlinuxC1,809 MB95,710370 ms6.0 ms451.8 ms26.7 ms0.6 ms55 MB73 MB full scansearches for a string that matches nothing, so every indexed byte is read. the worst case.open bigis the largest source file, cold. file length does not matter: only the visible window is lexed.

linux kernel · rss across a session**−37 MB**after idle

px0 reclaims memory after 15 s of inactivity, so an open session settles back down.

language server path · goplsserver ready374 ms, paid once

document outline1.4 ms

go to definition1.5 ms

find all references3.0 ms

hover5.1 ms

px0 memory18 MB

gopls memory122 MB

Servers are separate processes, spawned on the first request for their language and shut down on exit. Without one, px0 falls back to a regex outline instantly.

02/why

Agents write.You verify.

Code now arrives from the terminal, not the keyboard. What is left for you is review, audit, and navigation, and that job needs one thing done exceptionally well: a zero-latency, distraction-free place to read, explore, and verify. Not an editor that takes seconds to boot and gigabytes to idle.

1. 01terminal drives generation Agents, harnesses, and orchestrators write the code, run the tests, and move the workflow along. agent 14 files changed ✓ 212 tests passed
2. 02you drive verification Follow symbol references, read the surrounding context, and check the architecture the change landed in. F12 definition Shift F12 refs Ctrl Shift F every call site
3. 03the old ide is overkill Booting an Electron suite with an extension host and a gigabyte-plus heap just to read agent output. 1,440 MB rss, 15+ processes 4 - 10 s to index the workspace

read-only is the feature

• +fuzzy file search, symbols, regex across the tree

• +go to definition, hover, find references (with an LSP)

• +jump into stdlib and module-cache sources the server points at

• +14 themes, word wrap, back and forward history

• -no write endpoints: the HTTP API reads, searches, and asks language servers

• -no extension host, no plugin marketplace, no Electron

• -no telemetry. the one outbound call is a daily release check to GitHub

• -binds 127.0.0.1 unless you pass -host

where it fits

• verifying agent outputopen the worktree, trace the references, close the tab
• auditing a codebaseread a 25,000-file monorepo on a laptop without the fans spinning up
• remote boxesrun on the server, tunnel one port, read in any browser
• beside your editorkeep vim or VS Code for the edits you still type

traditional IDE vs px0side-by-side

dimensiontraditional IDEpx0built fortyping code character by character, hosting pluginsreading, exploring, and verifying codebase memory (rss)~1,440 MB~16 MB80x to 90x lighterstartup cpu spike35% - 50%< 1%cold startseveral secondssub-millisecondprocess tree15+ Node.js / Electron processes1 static Go binaryworkspace indexingmulti-second background churn13 ms for redis, 370 ms for the linux kernelsetupconfig files, plugins, node, npmzero config, zero runtime

03/features

Everything for reading.Nothing else.

The navigation you reach for a hundred times a day, done in milliseconds, in a UI that renders only the lines you can see.

f.01navigate

Fuzzy everything

Files, symbols, and a full-tree regex scan behind three chords. Ranking favours basenames, word boundaries, and camelCase humps, the way fzf feels.

CtrlPgo to file1.3 ms

CtrlShiftOsymbols

CtrlShiftFregex scan26.8 ms

timings: django, 7,014 files

f.02highlight

~280 languages

Native tokenizing through Chroma. The server lexes a 1,000-line window padded with 400 lines of context, never the whole file, and caches rendered HTML under a 512 MB LRU budget.

gorusttypescriptpythoncc++zigluarubyjavakotlinswifthaskellocamlelixirsqlyamltomlnixbashprotobufhcl+ ~258

f.03render

Virtual rows

Opening a 400,000-line file costs the same as a 10-line one. Only the visible window plus 24 rows of overscan is mounted; scrolling recycles rows with a single transform.

400,000lines in file**~60DOM rows0.015%**mounted

f.04lsp · optional

Semantic when you want it

Zero-config detection of servers on your$PATH. Spawned lazily on first request, stopped on exit. Missing or crashed? Instant regex outline instead.

• gopls
• rust-analyzer
• typescript-language-server
• pyright · ruff
• clangd
• zls
• lua-language-server
• solargraph

f.05themes

14 built in

Tokyo Night by default, plus Paper, Catppuccin, Dracula, GitHub Dark, Gruvbox, Monokai, Nord, One Dark, Rose Pine, and Solarized. A theme is one CSS file of tokens.

f.06distribution

One static binary

HTML, CSS, and JS are embedded withgo:embed. No Electron, no Node, no CGO, no system libraries. Copy it to a box and run it.

px0 static, go:embed
├─ index · search · highlight · lsp
├─ web/     html css js, ~74 KB
└─ themes/  14 × css

f.07memory

Gives memory back

After 15 seconds without requests, px0 reclaims memory. A tab left open for the afternoon costs what an idle one should.

peak94 MB

30 s idle57 MB

linux kernel, after five full scans

04/arch

One process.No runtime.

A Go server that owns indexing, search, highlighting, and language servers, talking JSON to a zero-dependency ES module frontend. The speed comes from a pile of small, boring decisions.

browservanilla js

• virtual rows*~60 nodes*
• fuzzy & tree cache
• offscreen font measure
• rAF-throttled paint

px0 · one go process~16 MB

routerHTTP · JSON · pooled gzip

indexpaths + tree, .gitignore aware

searchparallel worker pool

highlightchroma, windowed, LRU

lsp managerlazy spawn, regex fallback

scavengerreclaims memory after 15 s idle

hostyours

• source tree*+ .gitignore*
• gopls · clangd · …on first use
• stdlib & module cacheallowlisted

index

walk semaphoreNumCPU × 4ignore rulessegment · suffix · path, regex lastdir symlinksskipped, no cyclesstartuplisten first, index in background highlight

hlChunk1,000 lineshlContext400 lineshlWindowBytes512 KBbgLimit2 MB exact passcacheBudget512 MB LRU search

fast rejectbytes.Contains on whole filebuffersreused per workercase foldin-place ASCII lowersnipLead32 runes frontend

live rows~60OVERSCAN24 rowspaintrequestAnimationFramemeasureoffscreen, sub-pixel ch

fuzzyScore() · weightsO(n) two-pass

query verbatim in basename+40

basename starts with query+20

start of a path or word+16

camelCase hump+14

inside the basename+14

consecutive run+12

exact case+4

gap between hits−min(gap, 12)path length−len / 8depth−2 per /Pass one proves every query rune is present. Pass two walks back from the last hit to pull matches as tight as possible. The same ranking feel as a dynamic program, in a linear scan.ARCHITECTURE.md →

05/keys

Hands stay onthe keyboard.

The chords you already know from your editor, plus one palette that switches mode on its first character. Press?inside px0 for the full sheet.

shortcuts12 bindings

• CtrlKuniversal palette, quick open
• CtrlPgo to file
• CtrlShiftPcommand palette
• CtrlShiftOgo to symbol in file
• CtrlShiftFsearch the whole workspace
• CtrlFfind in active file
• CtrlGjump to line
• F12/Ctrlclickgo to definition
• ShiftF12find all references
• hovertype signature and docs
• Ctrlhoverinspect identifier link
• Alt←/Alt→back, forward through history

palette prefixesCtrlK

• ∅fileslspsrv→ lspservers.go
• >commands\>wrap→ Toggle Word Wrap
• @symbols@score→ fuzzyScore
• :line:120→ go to line 120

06/cli

Point it at a directory.That’s the setup.

px0starts the local viewer, prints the URL, and opens your browser while the index builds in the background. Multiple instances walk forward to the next free port.

~ · zsh

$ px0 ~/src/linux

px0 0.1.0
  workspace:  /home/you/src/linux
  url:        http://127.0.0.1:7777

ctrl-c to stop
✓ indexed 95710 files  370ms
  · language servers: clangd (started on first use)

$ px0 -version
px0 0.1.0 (linux/amd64)

$ px0 -no-open -port 0 ~/src/api | cat
...
[OK] indexed 1855 files  13ms

flagsusage: px0 [flags] [directory]

flagdefaultdoes-port N7777port to listen on (0 picks an ephemeral free port)-host H127.0.0.1local address to bind-no-openfalsedo not launch the browser-no-lspfalseskip language servers, use the regex outline-no-colorfalsestrip ANSI escape sequences-quietfalsesuppress narration, errors still go to stderr-updatefalsecheck for and install the latest release-versionfalseprint version and architecture, then exit

07/install

One binary.Pick a way in.

Install, point it at a repository, and read. Language servers are optional and picked up from your$PATHwhenever they exist.

a· quick installmacos · linux · bsd

Installs or upgrades to the latest release.

VERSIONpin a release, defaultlatestINSTALL_DIR/usr/local/binor~/\.local/bin

b· prebuilt binary15 targets

darwinamd64arm64

linux386amd64armarm64riscv64

freebsdamd64arm64

openbsdamd64arm64

netbsdamd64

windows386amd64arm64

$ sudo install px0-0.1.0-darwin-arm64 /usr/local/bin/px0

GitHub releases →

c· from sourcego 1.24+

git clone https://github.com/px0-ai/px0.git
cd px0
make build
sudo install px0 /usr/local/bin/

No npm, no node, no CGO, no system libraries.make distcross-compiles all 15 targets.

optional · language servers for go to definition, hover, referencesclick a command to copy

languageserverinstallGogoplsRustrust-analyzerTypeScript / JavaScripttypescript-language-serverPythonpyright or ruffC / C++clangdZigzlsLualua-language-serverRubysolargraph

$px0

Your codebase, open in the time it takes to read this line.

Star on GitHub