v2

STON.fi v2 smart contract API - advanced contracts with vault architecture and gas optimization

API reference

Important: This API reference documents low-level smart contract methods and opcodes. For production applications, we strongly recommend using the official SDK + TonConnect instead of manually compiling BOCs and sending transactions. The SDK provides better developer experience, handles edge cases, and receives official support. Custom BOC compilation should only be used for specialized/advanced use cases.

Overview

The section contains separate documents for each smart contract used in AMM:

• Pool

• Router

• LpAccount

• LpWallet

• Vault

Example schemes

Example schemes can be found here:

• Swap examples

• Lp provide examples

• Vault examples

Op code list

A table with DEX v2 op codes:

• Op Codes

New DEX v2 features:

Swap

• custom payload & nested operations after swaps

• chain multiple swaps on the same Router

• chain multiple swaps on different v2 Routers

• custom refund address and payload on swap failure

• deadline for tx completion

Liquidity

• custom payload after liquidly provision

• improved initial liquidity locking management, no coins are lost anymore

• now always mints a maximum possible amount of lp tokens to user even if provision ratio is different from current one in Pool

• single side liquidity provision

• deadline for tx completion

Referral

• referral fees are stored in Vault contract

• custom referral fee value in each swap (maximum 1%)

Note: Protocol fees in DEX v2 are collected in ASK jetton.

Referral Fees

DEX v2 accumulates each swap's referral portion in a dedicated Vault contract (one per referrer × token pair). Fees can be configured in the 0.01 %–1 % range and must later be withdrawn by the referrer. See the Omniston referral fees guide (note: although the guide is Omniston-oriented, the referenced paragraph explains in detail how DEX V2 referral fees work).

You can inspect vault balances and accrual history using the Stats & Vaults REST API:

• GET /v1/wallets/{addr_str}/fee_vaults – lists all known vaults per referrer

• GET /v1/stats/fee_accruals – shows all operations that led to fee accrual for the referrer, filterable by period

• GET /v1/stats/fee_withdrawals – lists all withdrawals from the referrer's vaults, filterable by period

• GET /v1/stats/fees – returns aggregated referral fee metrics (for example, total accrued USD value) by time frame

All endpoints are documented in the Swagger UI.

pTON v2

• now uses a custom op code for ton transfers

• ton transfer to user is non-bouncable

• improved gas management

• can chain ton transfers between 2 pTON wallets (to chain pTON swaps on v2 Routers)

Other

• LpAccount and Vault are deleted if they have 0 tokens on balance to avoid paying storage cost

• better error management: no coins are lost if Pool doesn't exist / payload is not correct

• complete refactoring of the codebase and usage of libs in masterchain to make all operations cheaper

• fixed various excesses issues

• fixed some Pools having broken get_jetton_data

Removed

Pool

• off-chain get_expected_outputs

• off-chain get_expected_tokens

• off-chain get_expected_liquidity

• on-chain getter_expected_outputs

• on-chain getter_expected_tokens

• on-chain getter_expected_liquidity

• user-called collect_fees