Documentation

Weft 0.6.2 — 83 stdlib packages, 24 registry modules, agents, telecom, devops.

Your app / script ↑ 24 modules telecom · auth · router · config · warp · dataframe · mold ... (registry → vendor/) ↑ 83 stdlib llm · mcp · dns · tls · os · http · db · sysinfo · crypto ... (in the binary) ↑ Language + VM Result/? · match · enum · closures · channels · auto-fetch (lex → parse → compile → run)

Get started

Tutorial Your first hour with Weft. Install, write, run.

Build an app 9 end-to-end examples: REST API, CLI, voice agent, data pipeline, MCP server.

Cookbook 22 paste-ready recipes — searchable on this site.

Ecosystem map How all 83 stdlib + 24 modules fit together: agents, telecom, web, devops.

Install apt, dnf, macOS, Windows, from source.

Language

Language reference Full syntax, types, closures, enums, match, defer, Result, grouped imports. Syntax cheatsheet One-page quick reference. Error handling Result, ?, context, bail, ensure. Concurrency map/filter fan-out, spawn, channels, race, timeout.

Standard library (83 packages)

Stdlib reference All 83 packages grouped by area. Each has maturity label.

LLM providers OpenAI, Anthropic, Ollama, vLLM — one env switch.

Local LLMs Ollama and vLLM setup for offline use. Web & HTMX HTTP servers, static files, SSE, forms, cookies. CLI tools Flags, subcommands, prompts, exit codes. Data & SQL SQLite, Postgres, CSV, table transforms. DevOps & sysops sysinfo, proc, netutil, os, dns, tls, compress, encoding, shell. Charts & viz SVG/HTML charts from data.

Agents & AI

MCP integration Expose tools for AI assistants or connect to MCP servers.

mold — structured output Validate LLM JSON, JSON Schema, tool params. ml — embeddings & RAG Vectors, cosine similarity, RAG index. Fine-tuning Private training, LoRA, presets, air-gapped deployment. Pipelines Data processing and ETL pipelines.

Speech & ML

Deepgram — streaming STT Real-time speech-to-text via WebSocket. Nova-2, interim results, VAD.

ElevenLabs — streaming TTS Real-time text-to-speech. Bidirectional WebSocket for lowest latency.

ML inference ONNX Runtime, Triton, HuggingFace. Classify, embed, detect, batch.

Telecom

Telecom guide IVA voice agents, STT/TTS, DTMF, queues, CDR. FreeSWITCH ESL with frame-level parsing, Asterisk ARI.

FreeSWITCH ESL 42 ESL commands: connect, api, execute, subscribe, uuid operations, sofia, linger, reconnect with backoff.

Asterisk ARI 55+ REST operations: channels, bridges, recordings, device state, mailboxes, ring/moh/silence, applications, system info.

Call queues Priority queues, agent state tracking, skill-based routing, estimated wait time, callbacks.

Infrastructure automation

infra package Health checks (TCP/HTTP/DNS/process/disk/memory), service management, deploy patterns, cert monitoring, network diagnostics.

Deploy patterns Rolling restart with health checks, canary deploy, wait_for, retry_until.

Config management Template rendering ({{key}}), idempotent apply with backup, diff detection.

Host provisioning Package install (apt/dnf/brew), user management, host info, cert monitoring.

Numeric, data & ML

warp — validated NumPy-style arrays Typed strided arrays, broadcasting, advanced indexing, FFT, LU linear algebra, accelerator dispatch.

dataframe — pandas-inspired tables Series, multi-level index, null-aware stats, joins, rolling, CSV/JSON I/O, Warp interchange.

Native accelerators Fail-closed CUDA/ROCm/MLX plugin ABI. Tensor dispatch, trust model, capability-gated loading.

ML — autograd & training Reverse-mode scalar autodiff, minibatch training, checkpoints, classical trainers on packed Warp arrays.

Browser & WASM

Playground Try Weft in the browser — 8 examples, share links, server-side sandbox.

WASM runtime Async execution, browser Fetch HTTP, virtual filesystem (16MB/file, 64MB total), path traversal protection.

Registry modules (24 packages)

Package registry Browse, search, and install. Every module has a maturity label. auth Argon2id password hashing, HMAC, PBKDF2, tokens, OAuth helpers.

router Path params, middleware chains, HEAD/OPTIONS/405, URL decoding, CORS.

config Unified loader: .env, JSON, YAML, TOML with dot-path access and validation.

logger Structured logging: levels, JSON/text output, context fields, child loggers.

queue Synchronous in-memory job list with retries and dead-letter handling.

template HTML templating: layouts, partials, loops, conditionals, auto-escaping.

jwt · cache · retry · cron · semver · color · validate JWT decode, LRU cache, exponential backoff, task scheduling, semver, terminal colors, data validation.

Package manager Auto-fetch, grouped imports, git imports, vendor, lockfiles. Author a module Create, test, publish with ed25519 signing. Security & capabilities Threat model, capability sandboxing, trust boundaries, supply-chain tests.

Infrastructure

Cluster, Governor & Supervisor Distributed locks, node registry, token budgeting, process supervision.

Tooling

Tooling guide build, test (race/mem/timeout), lint, bench (compare/save), debug, profile, lsp, mcp, doc, info, outdated. Testing & benchmarks fn test_*, --race, --mem, --coverage. Bench with baselines and regression tracking. Production Timeouts, secrets, governor budgets, TLS monitoring, deploy checklist. Stability Fuzz, race, compatibility corpus, maturity labels. Roadmap Where we are, where we're going, what's out of scope. Contributing How to contribute: project structure, adding packages, PR workflow. Changelog What changed in each release.

Quick reference

Syntax	What it does
`x := 1`	Bind a value (immutable)
`let mut n = 0`	Mutable binding
`fn add(a, b) { a + b }`	Function (last expression returned)
`fn main -> Result { ... }`	Entry point with error handling
`expr?`	Propagate error (unwrap Ok or return Err)
`"hi $name"`	String interpolation
`x \|> f`	Pipeline
`match x { 1 { "one" } _ { "other" } }`	Pattern matching
`enum Shape { Circle(r) }`	Sum type with payload
`map(list, fn)`	Concurrent map (fan-out by default)
`spawn(fn, args...)`	Run in background
`ch := channel(n)`	Buffered channel
`use pkg`	Import stdlib or registry package (auto-fetch if missing)
`use { "auth" "config" }`	Grouped imports
`use "github.com/user/repo"`	Git import (auto-clone into vendor/)
`use "./lib.weft" as lib`	Import local file

CLI commands

Command	What it does
`weft run [--watch]`	Run a script, auto-reload on change
`weft build [-o myapp]`	Standalone executable (no weft needed on target)
`weft check [--types] [--strict]`	Type check (CI uses --strict)
`weft test [--race] [--mem] [--timeout N] [--coverage]`	Run tests
`weft bench [--save f.json] [--compare base.json]`	Benchmarks with regression tracking
`weft lint [path]`	Static analysis (unused imports, TODOs, line length)
`weft fmt [--check]`	Format code
`weft doc [path]`	Generate API docs from pub fn
`weft info`	System report (memory, disk, uptime, network)
`weft debug [--dap]`	Debugger (CLI or DAP for VS Code)
`weft profile file.weft`	Execution profiler
`weft mcp serve file.weft`	MCP tool server
`weft lsp`	Language server (completion, hover, rename, diagnostics)
`weft update`	Self-update with SHA-256 verification
`weft upgrade`	Upgrade installed packages
`weft outdated`	Check for newer package versions
`weft get <name>`	Install from registry or path
`weft publish --key name`	Publish to registry with ed25519 signing
`weft gen "task" -o out.weft`	LLM generates Weft code
`weft doctor`	Check environment
`weft stdlib [pkg[.member]]`	Browse stdlib (live probe for zero-arg functions)