STON.fi

STON.fi is an AMM-based decentralized exchange on TON. Historically one of the first full-featured DEXes in the ecosystem, it consistently sits near the top of TON DeFi rankings by trading volume and pool depth.

What it offers

STON.fi runs the classic constant-product model (xy=k), similar to Uniswap v2: liquidity sits in two-asset pools, prices are set by reserve ratios, and LPs are paid through swap fees collected from arbitrageurs and regular users.

Core operations:

• Swap. Trade TON against any listed jetton, or jetton-to-jetton with routing through TON as an intermediate hop.
• Add liquidity. Deposit a pair of assets into a pool and receive LP tokens that accrue swap fees.
• Remove liquidity. Burn LP tokens to withdraw the underlying assets.
• Farming. Stake LP tokens in incentive pools to earn additional emissions, often STON or partner tokens.

Technical notes

Contracts are written in FunC, open-source, and audited. Each pool is a separate smart contract; a router contract handles multi-hop swaps. The architecture is built on top of TEP-74 (the jetton standard), so listing a new token typically means deploying a pool.

Slippage and pool fees follow standard AMM conventions: 0.3% goes to LPs, with an optional protocol fee on top. The UI displays expected output and a worst-case slippage figure before each swap.

Integrations

STON.fi is accessible as a standalone web app, as a Telegram Mini App, and via TON Connect through dozens of third-party wallets and dApps. Tonkeeper, MyTonWallet, and the in-Telegram Wallet can route swaps through STON.fi directly from their built-in swap UIs without leaving the wallet.

For developers, a public SDK and REST API expose pool quotes, historical prices, and backend swap routing.

The STON token

The platform issues its own jetton, STON, as a governance token. It is used for voting on protocol parameters and for staking inside incentive programs. See the separate STON token entry for details.

Risks

• Slippage in thin pools. Not every jetton pair has deep liquidity; a large swap into a small pool will move the price meaningfully. Always check slippage.
• Scam tokens. Listing on STON.fi is essentially permissionless via TEP-74, so look-alike scam jettons appear in free-form search. Always verify the contract address against an official source.
• Smart-contract risk. Standard for any DEX: a bug in pool code could lead to LP losses. STON.fi has been through multiple audit rounds, but audits are not insurance.

STON.fi and DeDust together capture the majority of TON’s spot DEX volume. For larger swaps it pays to compare quotes on both venues before executing.