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Launch your own branded stablecoin, backed 1:1 by USDC reserves on Coinbase, with instant onchain liquidity. This documentation is for technical partners integrating with the Custom Stablecoins swap program. You’ll find everything you need to construct and submit swap transactions from your application or smart contract.

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Use cases

Branded payment tokens

Launch your own stablecoin for in-app payments and rewards while maintaining USDC liquidity

Loyalty and rewards

Issue branded tokens as rewards that users can seamlessly convert to USDC

Gaming economies

Create in-game currencies backed by USDC with instant redemption

DeFi protocols

Integrate custom stablecoins into DeFi applications with guaranteed USDC liquidity

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Key features

  • 1:1 USDC backing: Fully backed by USDC reserves on Coinbase
  • Instant swaps: Single-transaction settlement on Solana
  • Predictable pricing: Fixed 1:1 ratio with no slippage surprises
  • Flexible integration: API or Cross-Program Invocation (CPI) from Solana programs
  • Multi-decimal support: Automatic normalization for 6-9 decimal tokens

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Onchain liquidity

Stableswapper is the onchain liquidity program that powers instant swaps between USDC and any Custom Stablecoin issued through the program. Built on Solana, it provides the settlement layer partners need to let their users move freely between custom tokens and USDC. Learn how to integrate swaps into your application.

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How it works

The Stableswapper program maintains a liquidity pool with separate vaults for each supported token.
1

User initiates swap

The input token is sent to the appropriate vault
2

Validation

The program checks the whitelist (if enabled), validates slippage protection, and applies any configured fee
3

Settlement

The equivalent amount of the output token is sent from the output vault to the destination account
Swaps settle atomically in a single Solana transaction at a 1:1 ratio before fees, with automatic decimal normalization between tokens with different precision (6-9 decimals).

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Concepts

ConceptDescription
PDA (Program Derived Address)Deterministic on-chain account owned by the program — used for the pool, vaults, and whitelist
VaultA PDA that acts as the logical owner for a token’s reserves within the pool
Vault Token AccountThe SPL token account that actually holds the token reserves for a given vault
ATA (Associated Token Account)A user’s standard token account for a given mint, derived deterministically from their wallet
WhitelistAn optional on-chain list of authorized wallet addresses. When enabled, only listed addresses can execute swaps
SlippageThe minimum acceptable output amount (min_amount_out). Protects against fee changes between transaction construction and execution

Quickstart

Get up and running with your first swap in 10 minutes

Reference

Swap instruction parameters and accounts

Production Readiness

Helper functions, error handling, and best practices

Key Addresses

Program IDs, token mints, and deployed addresses