Introducing Codex Par — Instant 1:1 USDT and USDC Swaps, via API

Today, we are launching Codex Par, our 1:1 stablecoin swap API that lets payment operators give customers USDT and USDC conversion at par.

No spread for the customer and no swap infrastructure for you to build. Codex handles liquidity and settlement, so the two halves of the onchain dollar behave as one asset inside your product.

A Dollar Isn't Always a Dollar

USDT and USDC hold more than $250 billion in combined circulation, roughly 85 percent of all stablecoin value, yet they do not trade as the same dollar. They are separate instruments from separate issuers that trade against each other at a spread.

In calm markets it is a few basis points; under stress it widens sharply. In March 2023, USDC traded below 90 cents while USDT held near a dollar. That variability is the real problem as you cannot price in a cost you don't know.

Your customers never see any of this. They send 1,000 USDT and expect 1,000 USDC on the other side. Honoring that means sourcing both stablecoins and wearing the market risk between them on every transaction. At payment volume, you are quietly running an FX desk between two versions of the same currency, next to the product you actually sell.

How Codex Par Works

Codex Par sits behind your product. You call one API endpoint and get a 1:1 quote, in either direction, every time. There is no spread logic or conversion accounting to build or reconcile. Your customer sees par with no fee. Your cost is billed separately on volume tiers, so your margin stays yours.

There is nothing to prefund, since Codex manages liquidity on both sides, and Codex can run against the KYB you have already done on your customers.

Codex Par vs. Alternatives

Operators reach par one of two ways today, and both get expensive as volume grows.

Versus onchain: Swapping onchain means a rate that moves with the market and pools that thin out under load, plus gas you can't forecast. Codex Par fixes the rate at 1:1 on institutional liquidity sized for real flow.

Versus in-house: Doing it yourself means wearing the full spread and locking up capital as inventory. Codex Par takes that off your balance sheet and settles inside a defined window, 24/7/365.

Codex Par supports USDC on Ethereum, Solana, Polygon, Base, Optimism, Arbitrum, Avalanche, and Codex, and USDT on Ethereum, Solana, Tron, and Polygon.

Part of The Dollar Machine

Codex Par is the newest piece of The Dollar Machine, our push to make dollars feel the same everywhere: on-ramps from US fiat, off-ramps back into it, stablecoin conversion, and local currency access across Latin America, Asia, Africa, and more. It is the base of a longer build: a full onchain FX platform moving any currency into any other at real rates, without correspondent banking chains. The dollar sits on one side of roughly nine in ten global FX trades, so the build starts there.

When the two most widely held dollar stablecoins act as one asset for your customers, a dollar keeps feeling like a dollar, onchain.

Get Started

Codex Par has been live in production since early 2026 and clears hundreds of millions in swap volume each month, as the wider Codex FX platform crossed $1 billion in monthly volume recently only three months after going live.

If your customers move between USDC and USDT, whether you are a PSP, wallet, remittance company, or crypto payment processor, book a demo and we'll show you what par looks like at scale.