Polymarket enables sub-second Bitcoin Lightning deposits

Polymarket enabled instant Bitcoin deposits over the Lightning Network, crediting funds in under one second by using the Spark protocol developed by Lightspark. The new route replaces onchain deposits that previously took 10–60 minutes and required three to six confirmations before accounts were credited.

Spark validates a bitcoin transfer at the moment it is broadcast, checking for double-spend risk, fee adequacy and replace-by-fee flags before the platform credits the deposit. The protocol uses statechain technology to track ownership off the main Bitcoin chain while keeping control of funds with the user’s private keys.

Polymarket noted the upgrade reduces funding latency and lowers fees. The exchange does not need to run its own Lightning nodes or set confirmation thresholds after integrating Spark’s software development kit, which handles onchain, Lightning and stablecoin rails. Wallets remain self-custodial and tied to each user’s private keys until a trade is placed.

Polymarket first added onchain bitcoin deposits in October 2025; those deposits required three to six confirmations and carried higher minimums to cover bridging costs. The Lightning route settles in seconds and typically incurs near-zero fees, allowing lower minimum deposits.

Wallet providers including Breez, Xverse and Cake are building on Spark. Tether CEO Paolo Ardoino described the technology as ‘A route to programmable Bitcoin over Lightning.’

The upgrade arrives as Polymarket competes with regulated rival Kalshi. Kalshi reported $5.42 billion in taker volume for April, while Polymarket reported $1.99 billion for the same month. Polymarket has also added perpetual futures for U.S. markets to expand its product set.

Polymarket’s Lightning rails give the platform direct access to bitcoin holders and remove a conversion step that previously led some users to fund accounts with stablecoins.