Tether on 14 August said it has integrated Lightspark’s ‘Spark’ Bitcoin Lightning infrastructure into its open-source Wallet Development Kit, a move the stable-coin issuer says will allow developers to build non-custodial wallets that handle instant, low-cost payments in both bitcoin and its USD₮ token via a single API. The company described the upgrade as a step toward “a more inclusive financial future,” noting that Spark enables support for native Bitcoin Layer 1, Lightning and stable-coin transactions across mobile, web and embedded devices without relying on custodial services. Paolo Ardoino, Tether’s chief executive, said the change “will empower innovators to develop programmable and resilient monetary systems.” Lightspark co-founder and CEO David Marcus called the partnership a chance to deliver “fast, cheap, real-time Bitcoin” to a wider audience and predicted WDK could capture a significant share of consumer payments. The toolkit will be fully open-sourced “soon,” according to Tether, which views the integration as foundational for future applications, including AI-driven autonomous agents that transact in bitcoin and USD₮.