Tolk — the language for TON

Tolk is a statically typed language designed for TON smart contracts.

It provides declarative structures, automatic cell serialization, first-class message handling, and a modern development experience.

The language compiles to TVM (TON virtual machine) with zero overhead and full control over execution.

type AllowedMessage = CounterIncrement | CounterReset

fun onInternalMessage(in: InMessage) {
    val msg = lazy AllowedMessage.fromSlice(in.body);
    match (msg) {
        CounterIncrement => { ... }
        CounterReset => { ... }
    }
}

get fun currentCounter() {
    val storage = lazy Storage.load();
    return storage.counter;
}

Key features

Tolk offers high-level readability while remaining low-level in nature:

• a robust type system to express any cell layout in TON
• lazy loading: unused fields are skipped automatically
• unified message composition and deployment
• a gas-efficient compiler targeting the Fift assembler
• friendly tooling and IDE integration

Tolk is a replacement for FunC

Tolk started as an evolution of FunC and is now the recommended language for TON smart contracts.

If you are migrating from FunC:

• Look through benchmarks: notice 30–50% lower gas fees.
• Scan the page Tolk vs FunC to get the overall picture.
• Use the FunC-to-Tolk converter to migrate existing projects.

Quick start

1. Run the command:

   npm create ton@latest
   

2. Enter a project name and choose “simple counter contract”.

3. Follow the “Your first smart contract” article to get explanations.

IDE support

All major IDEs support syntax highlighting and code completion:

1. JetBrains IDEs (WebStorm, CLion, etc.) — via the plugin
   => install “TON” from Marketplace, read more

2. VS Code — via the TON extension
   => install “TON” from Marketplace, read more

3. Cursor and Windsurf — via the OpenVSX registry
   => install from the website, read more

4. Neovim, Vim, Zed, etc. — via the language server
   => download an archive, consult the link above

Where to go next

Recommended starting points:

• Basic syntax
• Idioms and conventions
• Type system
• Message handling

External resources

Useful links outside this documentation:

• TON Dev chats in Telegram
• @tolk_lang channel in Telegram
• GitHub for issues and sources