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Sava Milanov
Sava Milanov

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SDEV Programming Language

#programming #sdev #language #development

sdev is here.

Today, July 12, 2026, sdev goes live.

If you've never heard of it: sdev is a new programming language. It runs in your browser, in a full IDE, without an install. It has a syntax nothing like Python or JavaScript. It ships with a bytecode virtual machine, a virtual kernel, a Web DSL, Leaflet integration, a package system, a 26-language keyword translator, a VS Code extension, and a full-length book in two languages. And its compiler is written in itself.

Here's how it got here, and what you can do with it.

Why sdev exists

Every popular programming language today was designed for people who already program. The people they were designed for don't need print(x) to be more readable, because they've long since stopped reading it as "print, open paren, x, close paren" — they read it as one word. But for someone opening a code editor for the first time, that punctuation isn't invisible. It's a wall.

sdev's premise is that the wall is optional. Not every language has to be built for the people who have already scaled it.

So the syntax reads out loud:

set greeting to "hello, world"
say greeting

for each n in [1, 2, 3]
  say n * 10
end
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say beats print(...) every time I run this test with a non-programmer. set … to beats = and let. for each … in … end beats for (;;) and for … :. None of these choices are arbitrary; they're all the result of watching real people fail to guess what mainstream syntax means.

But a beginner-friendly language that can't do real work isn't a language. It's a toy. So sdev also had to be real.

What "real" means, on day one

  • A bytecode VM. Not a tree-walking interpreter — a proper stack-based virtual machine, with a .sdevc binary format and a documented opcode set.

  • A virtual kernel. Tasks, syscalls, a mark-and-sweep garbage collector.

  • A browser IDE. File tree, terminal, debugger, live canvas preview, live web preview, autocomplete, syntax highlighting, minimap, find/replace, go-to-line, problems panel, command palette.

  • A Web DSL. page, h1, p, style { … }, onclick { … }, plus raw_html / raw_css / raw_js escape hatches. A complete HTML document, in six lines of sdev.

  • Leaflet interop. A live map with markers, popups, polygons, and layers, in two lines.

  • A decentralized package system. summon "gist-url" pulls a library straight from GitHub Gists. No central registry, no lock file, no npm.

  • A 26-language keyword translator. Write sdev in Bulgarian, Japanese, Portuguese, Arabic — the AST is the same. A child in Sofia and a child in Osaka can write the same program in their own languages.

  • A self-hosted compiler. Which brings us to the part I'm most proud of.

The compiler compiles itself

sdev's v2 compiler is written in sdev.

The bootstrap chain runs like this:

  1. Stage 0 — a hand-written WebAssembly seed VM (lang/bootstrap/seed.wat, about four kilobytes of .wat) with a fixed linear-memory layout and two host imports for output.

  2. Stage 1 — a JavaScript "reference compiler" (lang/bootstrap/compile.mjs) that lowers sdev source to seed bytecode. Its only job is to be replaced.

  3. Stage 2 — lang/compiler/lexer.sdev, parser.sdev, and codegen.sdev. The real compiler, written in sdev, loaded through the seed VM.

  4. Stage 3 — lang/compiler/compile-self.mjs, a thin shim that exposes the self-hosted pipeline as a drop-in replacement for the JS reference.

As of today, lexer.sdev and parser.sdev compile byte-identically through the self-hosted pipeline versus the JS reference. Same bytecode. Same string pool. Down to the last byte. codegen.sdev itself is one memory-widening away.

Once that widening lands (next milestone), the JS bootstrap gets deleted. sdev will compile itself, from source, entirely through sdev-authored code running on a hand-written WebAssembly seed.

I don't know of another beginner-first language that has done this.

What's next

  • Milestone 5n — widen the seed VM so codegen.sdev round-trips.
  • Milestone 5o — delete the JS bootstrap.
  • Native x64 codegen — already scaffolded in lang/native/.
  • Hardware DSL — sdev programs that lower to Arduino/ESP32 C++, for the maker crowd.
  • Pro tier — desktop app, cloud sync, private Gists.

Try it now

Open the IDE. Type say "hello, world". Hit run. You'll see it work. Then poke around at the example Gists, or read the book, or write your own program.

→ https://web.sdev.codes

No signup needed to run code. Signup is only for saving files and publishing Gists.

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