NURL

v0.90.0

A compiled language without a virtual machine, garbage collector, or interpreter — designed as a target for LLM code generation, with deterministic builds and native LLVM performance.

Start with NURL Open Playground

78,880lines of NURL in the compiler

1,687compiler test programs

243stdlib modules

11tested targets

65registry packages

Contributors

Hindurable

iljasrb

WHY NURL

Built for generated code

NURL keeps generated code easy to parse. Fixed arity removes precedence ambiguity, short dependency windows limit context, and the grammar fits on one page.

Regular prefix-arity grammar

Every operator has a fixed arity. There is no infix syntax or precedence table.

Local semantics

A token’s meaning depends on a short span of preceding tokens.

Single-owner memory

Values auto-drop at scope exit. Borrow checking, an explicit unsafe/raw boundary, and a mechanized Lean 4 proof (formal/) guarantee memory safety.

Deterministic compiler

Bootstrap compiles the compiler twice and requires identical LLVM IR from both runs.

LLVM-backed

One LLVM pipeline targets desktops, servers, WebAssembly, RISC-V, and embedded systems.

Self-hosting

The compiler is written in NURL and builds itself from source.

SYNTAX

Prefix notation, end to end

NURL uses OP ARG1 ARG2 …. There is no operator precedence or infix syntax.

Add two integers

@ add i a i b → i { ^ + a b }

( add 3 4 )     // → 7

FizzBuzz

: ~ i i 1
~ <= i 100 {
    ? == 0 % i 15 { ( nurl_print `FizzBuzz\n` ) }
    ? == 0 % i 3  { ( nurl_print `Fizz\n` ) }
    ? == 0 % i 5  { ( nurl_print `Buzz\n` ) }
    { ( nurl_println_int i ) }
    = i + i 1
}

See the language reference for generics, traits, pattern matching, errors, channels, compile-time evaluation, and async runtime support.

BENCHMARKS

Measured runtime performance

20 verified benchmarks compare NURL with C, Rust, Node, and Python. Each implementation must produce the same output before timing.

5 languagesGitHub Actions ubuntu-latest runnerMeasured 2026-11-07Benchmark sources →CI run →

Benchmark runtime in milliseconds; lower is better.
Benchmark	NURL	C	Rust	Node	Python
`lcg`20M-step 64-bit LCG + xorshift	41 ms	41 ms	41 ms	1,813 ms	4,963 ms
`packet_classifier`25M unpredictable branches	59 ms	58 ms	59 ms	169 ms	4,056 ms
`ring_write`20M ring-buffer stores	44 ms	44 ms	45 ms	71 ms	6,220 ms
`histogram_bins`20M binned increments	42 ms	43 ms	43 ms	75 ms	5,671 ms
`prefix_scan`1M 16-wide prefix scans	24 ms	24 ms	24 ms	69 ms	4,445 ms
`binary_search`5M lower-bound searches	42 ms	40 ms	43 ms	111 ms	5,973 ms
`sort_window`2M 8-element bubble sorts	29 ms	29 ms	29 ms	199 ms	11,923 ms
`bloom_filter`4M Bloom-filter queries	19 ms	20 ms	21 ms	2,771 ms	6,964 ms
`hash_join`5M hash-table probes	29 ms	29 ms	32 ms	3,458 ms	7,757 ms
`sieve`Sieve of Eratosthenes to 10M	26 ms	24 ms	25 ms	75 ms	3,444 ms
`fib`Recursive fib(35)	28 ms	33 ms	33 ms	138 ms	1,154 ms
`collatz`Longest Collatz chain below 100k	15 ms	14 ms	15 ms	56 ms	714 ms
`matmul`256x256 integer matrix product	36 ms	35 ms	36 ms	77 ms	3,138 ms
`json_parse`20 parses of a 64 KB document	8.4 ms	14 ms	19 ms	41 ms	37 ms
`nbody`500k n-body integration steps	26 ms	42 ms	28 ms	105 ms	3,006 ms
`chacha20`ChaCha20 over 16 MiB (RFC 8439)	9.9 ms	44 ms	36 ms	n/a	n/a
`poly1305`Poly1305 MACs over 64 MiB (RFC 8439)	14 ms	34 ms	23 ms	n/a	n/a
`blake2b`BLAKE2b-512 over 32 MiB (RFC 7693)	46 ms	67 ms	71 ms	n/a	n/a
`sha512`SHA-512 over 16 MiB (FIPS 180-4)	50 ms	50 ms	52 ms	n/a	n/a
`x25519`1000 chained X25519 scalar mults (RFC 7748)	35 ms	51 ms	52 ms	n/a	n/a

Median wall-clock time for the full process. Lower is better. NURL is highlighted only when its displayed time is lower than every other displayed time.

GET STARTED

Start with NURL

Try it in the browser

Write, build, and run NURL in your browser.

Open the Playground →

Install a release

curl -fsSL https://nurl-lang.org/install.sh | sh
irm https://nurl-lang.org/install.ps1 | iex

Install guide →

Build from source

git clone https://github.com/nurl-lang/nurl
cd nurl && ./build.sh

View the repository →

Editor support

The VS Code extension also works in Cursor and Windsurf, with diagnostics, completion, and formatting.

Editor guide →

TARGETS

One LLVM pipeline across targets

The compiler emits target-agnostic LLVM IR for desktop, server, browser, unikernel, and embedded targets.

Linux x86_64

Windows x86_64

macOS x86_64 and ARM64

FreeBSD x86_64

WebAssembly

Linux ARM64

Linux RISC-V64

Unikernel x86_64, ARM64, and RISC-V64

Milk-V Duo

ESP32 Xtensa

ESP32-C3/C6

Embedded hardware. NURL runs an HTTP file server on the Milk-V Duo and drives ESP32 GPIO through memory-mapped registers.

Browser builds. The playground compiles to wasm32-wasi in your tab and can cross-compile downloadable native binaries.

Bootable programs. The unikernel path links NURL programs without a host OS for x64, ARM64, and RISC-V targets.

STANDARD LIBRARY

243 modules, included with the toolchain

The standard library is plain NURL source: core types, general-purpose modules, and optional higher-level integrations.

Network

TCP, UDP, Post-Quantum TLS 1.3, QUIC, HTTP/1.1, HTTP/2, HTTP/3, WebSocket, MQTT, SMTP, and peer-to-peer networking.

Data

JSON, Protobuf, Zstandard, TOML, YAML, XML, MessagePack, CBOR, CSV, PostgreSQL, and SQLite.

Concurrency

Threads, mutexes, channels, atomics, and a stackful M:N async runtime.

Core

Collections, arbitrary-precision numbers, regex, crypto, compression, UUIDs, paths, and processes.

AI and MCP

Anthropic API support plus MCP clients, servers, sessions, and registries.

Tooling

LSP, formatter, documentation tools, test and benchmark runners, and a differential fuzzer.

Browse the standard library →

PROJECTS

NURL projects

The compiler itself

A self-hosting compiler that produces identical LLVM IR in two compilation rounds.

Explore →

A Game Boy emulator

A complete DMG emulator compiled to WebAssembly for the browser.

Explore →

The playground backend

NURL serves the playground, build service, MCP endpoint, and package registry.

Explore →

Examples

Examples include Game of Life, HTTP/2, MCP servers, agents, and embedded targets.

Explore →

PACKAGES

Packages, one command away

The registry supports semver ranges, reproducible lockfiles, and signed tarballs verified by nurlpkg before unpacking.

nurlpkg search whisper
nurlpkg install nq
nurlpkg add tensor
nurlpkg publish

Browse the registry →

nurllama

whisper

onnx

tensor

grad

yoloe

nwasm

image

MCP SERVER

NURL tools for agents

Connect an MCP client to build, run, and cross-compile NURL without a local toolchain.

claude mcp add --transport http nurl https://play.nurl-lang.org/mcp

Read the MCP setup guide →

REFERENCES

Source, specification, and release history

Documentation

Guides and language reference for installing, writing, and running NURL.

Read the docs →

README

A repository overview of the language, runtime, and build pipeline.

Open README →

Formal grammar

The versioned EBNF grammar and historical snapshots.

Open grammar →

Formal proof (Lean 4)

30,200+ lines of Lean 4 mechanizing NURL’s memory model (A1 & A2): structs, enums, closures, panics, and leak freedom.

Interactive explorer →GitHub source →

Changelog

A release-by-release record of changes.

Read changelog →

Roadmap

Current work and plans toward 1.0.

Read roadmap →

Package registry

Browse packages, source, and generated API documentation.

Open registry →