What is OKB (OKB)?
OKB was launched in 2018 by OKX, then called OKEx, as the utility token of its exchange and was originally issued on Ethereum. In August 2025 OKX made it the only gas and native token of X Layer, its own Ethereum layer-2 network, and began phasing out the Ethereum version.
- Type
- Gas token of an Ethereum layer-2
- Launched
- 2018
- Consensus
- Optimistic rollup on the OP Stack (X Layer)
- Max supply
- 21 million OKB (fixed since 2025)
- Swap network
- X Layer
How OKB works
X Layer went live in April 2024 as a zkEVM built with Polygon's CDK. It has since moved to the OP Stack, a migration Optimism announced in December 2025, and now runs as an optimistic rollup with one-second blocks that settles to Ethereum through Polygon's AggLayer. Every transaction on X Layer pays its gas in OKB.
What OKB is used for
OKB covers gas fees on X Layer and serves as a base asset for the DeFi, payments and trading apps built there. On the OKX exchange it has long been tied to perks such as trading fee discounts.
OKB supply
In August 2025 OKX burned 65,256,712 OKB accumulated from past buybacks, upgraded the token contract to remove its mint and burn functions, and fixed the total supply at 21 million OKB. OKT, the coin of OKX's older OKTChain, was converted into OKB as that chain was retired.
Before you swap OKB
OKB here is the native coin of X Layer (chain ID 196), received at a standard 0x address. OKX no longer supports OKB withdrawals to Ethereum, so make sure the receiving wallet or exchange expects OKB on X Layer rather than the old ERC-20 version.