Bitcoin-only app Relai taps Blockstream Greenlight for Lightning payments

Source: Cointelegraph

Users of the Swiss-based Bitcoin-only app Relai are set to unlock Lightning payment functionality following its integration with Blockstream’s Greenlight solution.

According to an announcement shared with Cointelegraph unpacking details of the collaboration, Blockstream’s Lightning-as-a-service solution is being integrated into Relai’s Bitcoin-only wallet platform.

Greenlight’s functionality is set to allow 100,000 Relai users to make low-cost Bitcoin BTC $72,767 payments using the Lightning Network while maintaining control of their private keys. Integrating Greenlight also means Relai does not have to build and maintain bespoke Lightning infrastructure.

Blockstream launched Greenlight in June 2023 as an alternative service for developers and platforms to provide fast, low-fee Bitcoin payments. The service hinges on using Blockstream’s infrastructure while preserving user control over private keys.

Custodial solutions are an alternative option that offers quick onboarding and convenience, but these typically compromise security and privacy guarantees for users. Noncustodial solutions prioritize security and privacy but require more technical and operational resources.

Greenlight’s approach to enable custodial Lightning splits nodes into smaller components that operate separately. Using Core Lightning as the base implementation, Greenlight allows all operations involving private keys to be performed on a user’s device as the signer. The remainder of the node and operational needs run on Blockstream’s infrastructure.

A visualization of Blockstream’s Greenlight architecture, which allows users to maintain sole control of their Bitcoin private keys. Source: Blockstream.

Blockstream built its signer on the Validating Lightning Signer project to ensure end-to-end verification. This means only users can initiate operations involving their funds, not the infrastructure operator or anyone with similar control or access.

The design is similar to hardware wallets, where a user has a client interface and signer, while the wallet provider operates a Bitcoin node that connects to the network. User-controlled elements can initiate payments and sign invoices while Blockstream runs the node.

Relai was founded in 2020 with a sole focus on Bitcoin trading and custody. The app has generated over $300 million in trading volume over the past four years. Relai’s decision to onboard Lightning payments comes off the heels of some of the biggest exchanges looking to improve their Bitcoin payment functionality.

Coinbase, the largest exchange operator in the United States, announced that it would integrate Bitcoin Lightning payments into its offering in September 2023. Coinbase CEO Brian Armstrong cited Bitcoin’s position as the most important asset in the cryptocurrency ecosystem and said that its functionality would help facilitate faster and cheaper BTC transactions.