The Spark protocol brings self-custodial deposits over Lightning Network to Polymarket, marking a concrete integration of the Bitcoin layer 2 into prediction markets.
Polymarket has activated Bitcoin deposits via Lightning Network, using the infrastructure of the Spark protocol. Spark announced the development in a post on X.
The integration follows a step already taken in October 2025, when Polymarket had enabled on-chain Bitcoin deposits. That method required three to six on-chain confirmations – a window of between ten and sixty minutes before the platform credited the funds. The minimum deposit was higher, owing to bridging costs: for a user looking to open a position on a live market, both the wait and the cost represent real friction.
Spark addresses both issues through a mechanism called zero-conf: the protocol validates the transaction at the moment it is broadcast to the network, checking for double-spend risk, fee adequacy, and replace-by-fee flags. The deposit is credited in under one second, and confirmation risk is absorbed by the protocol itself. Polymarket does not need to manage confirmation thresholds or operate its own Lightning nodes: a single Spark SDK handles on-chain, Lightning, and stablecoin rails together.
What sets this integration apart from a straightforward technical optimisation is the self-custodial nature of the deposits. Each wallet is tied to the user’s own keys: the protocol, not Polymarket, carries the operational load, and the user retains control of funds up to the moment of the transaction. Building on the same stack are wallet providers such as Breez, Xverse, and Cake; Tether CEO Paolo Ardoino has described Spark as a path toward programmable Bitcoin on Lightning.
