1:1 USDT ↔ USDC swaps, via API
Codex Par is a 1:1 stablecoin swap API for payment operators. Offer your customers USDT↔USDC conversion at par with no extra cost for them. We handle the liquidity and settlement.
Book demoPOST /v1/swap { "from": "USDC", "to": "USDT", "amount": "1000000.00", "rate": "1.000000", "receive": "1000000.00" }
Market rate shown is illustrative.
Dragonfly
Coinbase Ventures
Circle Ventures
Wintermute
CumberlandIn a bank, a dollar is a dollar. Onchain, it isn’t.
USDT and USDC are separate instruments from separate issuers, and they trade at a spread. A few basis points in calm markets, or far more under stress.
Your customers don’t know that. They expect 1,000 USDC when they swap or send 1,000 USDT. Someone has to source the liquidity, absorb the spread, and carry the exposure to meet that expectation.
That’s what Codex Par is for.
How 1:1 swaps work
Codex Par sits behind your product, managing the liquidity and settlement. You keep the customer relationship and the economics, whether your customers convert USDT to USDC or USDC to USDT.
Request swap
Call the API endpoint. Every rate returned is 1:1, in both directions. No visible spread or conversion fee for your customers.
POST /v1/swap { “from”: “USDC”, “to”: “USDT”, “amount”: “1000000.00”, “rate”: “1.000000”, “receive”: “1000000.00” }
Execute swap
Codex Par executes the USDT/USDC swap, 24/7/365, within a defined settlement window. Not a best-effort fill with no guaranteed time.
Get billed transparently
Your customers always see 1:1. Your cost is invoiced separately and volume dependent. You always know what you pay, and why.
50,000
USDCReceive
50,000
USDT
Why Codex Par
There are multiple ways to give a customer par on USDT and USDC swaps. Only one of them scales.
Onchain
In-house
Rate
Settlement
Liquidity
Cost
Anyone can quote 1:1. Keeping it at scale is the hard part.
Live in production
since early 2026
Hundreds of millions
in monthly volume
Our customers move between USDT and USDC constantly. Codex Par lets us offer them par pricing without sourcing liquidity or carrying the spread ourselves — the integration was a single endpoint.
APAC Payment Operator
Head of Product
FAQ
Find answers about how Codex Par works, pricing, supported chains, and more.
Codex Par is a 1:1 stablecoin swap API. Payment operators use it to offer their customers USDT ↔ USDC conversion at par, while Codex manages the liquidity and settlement behind the scenes.
Payment operators with downstream customers moving between USDC and USDT, such as PSPs, wallets, remittance companies, and crypto payment processors.
On the open market, USDT and USDC trade at a spread, plus venue fees or gas. But through Codex Par, your customers pay no fee and see no spread. Every swap executes at exactly 1:1. Your cost as the operator is invoiced separately and volume dependent. You always know what you pay, and why.
USDC on Ethereum, Solana, Polygon, Codex, Base, Optimism, Arbitrum, and Avalanche. USDT on Ethereum, Solana, Tron, and Polygon.
Codex can rely on the KYB you've already performed on your customers. The KYB is subject to periodic sample testing so you can keep the relationship.
No. Codex holds and manages the liquidity for you on both sides so you don't need to.
One API key, one endpoint. Every rate returned is 1:1, in both directions.