GMX is a decentralized spot and perpetual exchange running on Arbitrum and Avalanche. GMX allows users to leverage trade various assets and contains stop-loss orders, take-profit orders, no price-impact trades, and staking for the platform's utility and governance token.
GMX started as Gambit Protocol, which was launched on Binance Smart Chain and initially focused on creating a partially backed stablecoin that automatically generated interest (USDG). Essentially, a stablecoin backed by leverage. Gambit's native token was GMT which had a whitelist presale in early March 2021. Within three weeks of launching on mainnet, Gambit recorded $400m of volume and $380k in fees. In June, the name GMX started to take shape after a proposal passed to merge all four different protocol tokens into a single token called GMX. With this change, GMX (still named Gambit at this time) also removed the backed-by-leverage stablecoin aspect of the protocol. Instead of users providing liquidity to a whitelisted asset and receiving USDG in return, they will receive GLP.
In August 2021, GMX posted a Medium article detailing the launch plans to Arbitrum. The contracts were deployed in July, but Arbitrum had not yet opened to the public.
The GMX trading platform launched on Arbitrum on September 1st, 2021. Within two weeks after launching GMX handled a volume of $150m and earned $300k in fees.
As of April 28th 2022, GMX has $341m total value locked (TVL).
The three main tokens associated with GMX are GMX, esGMX, and GLP.
GMX tokens are used for governance and can be staked for a share of swap and leverage fees. 30% of swap and leverage fees are converted to ETH on Arbitrum or AVAX on Avalanche and distributed to stakers of GMX tokens. 
70% of swap and leverage fees are distributed to GLP token holders in ETH on Arbitrum or AVAX on Avalanche. 
GLP (GMX Liquidity Provider) tokens can be minted with any asset supported by GMX on the chain the user is interacting on and can be redeemed for any other asset in the pool. GLP token holders also earn esGMX (escrowed GMX rewards) which can be staked like GMX or vested to become GMX tokens over the course of a year.