Spark is a web-based GUI wallet designed for speed, safety and simplicity that utilizes Blockstream’s Lightning implementation c-lightning as its backend. The platform allows for easy spending and receiving of bitcoins over the Lightning Network, which is renowned for its payment speeds. Users can also run their own Bitcoin-based nodes, c-lightning nodes and Spark GUIs in a completely trustless environment.



Independent developer Nadav Ivgi is the developer behind the project. Also an ambassador at the Tel Aviv Bitcoin Embassy and the founder of Bitrated, a company that seeks to bring stronger consumer protection to blockchain applications, Ivgi developed Spark through a sponsorship from blockchain development company Blockstream.

Speaking with Bitcoin Magazine, he says Spark is a “purely off-chain wallet that provides a simple way to send and receive Lightning payments on multiple platforms. Spark is free and open-source software released under the terms of the MIT license.”

Spark provides users with a simple and minimalistic interface, designed to make things easy even for those with minimal crypto experience. It also includes automatic self-signed certificates, along with LetsEncrypt integration and Tor hidden service (v3) support for broader safety and security.

According to Ivgi, Spark can be used in three different ways, the first being through web browsers from any desktop or mobile devices. “For this, users need to set up Spark as a web server alongside their c-lightning node, which they can then access from everywhere over the web,” he comments.

Spark can also be used via desktop apps for Linux, macOS and Windows. These apps can connect directly to the c-lightning node and don’t require a Spark server setup. Lastly, Spark can be used with an Android mobile app, which connects to the Spark server and acts as a “remote control” for a c-lightning node hosted at home or on the cloud. Though only compatible with Android, at present, Ivgi says iOS will soon be an option.

Once Spark is started, the platform generates and prints a random username and password that the customer can utilize to log into the wallet. They can then customize their credentials once this first step is completed and bind an address to the app, which will allow them to access Spark remotely in the future.

Ivgi says that LetsEncrypt and Tor allow remote clients to access their accounts while enjoying the highest level of privacy. “When configured to accept remote connections, Spark will automatically enable TLS encryption with a self-signed certificate,” he explains. “This improves security but causes browsers to display a security warning about the certificate not being “certificate authority” (CA) signed. To make getting a CA-signed certificate as easy as possible, Spark has a built-in integration with LetsEncrypt, a certificate authority that gives free certificates with an automated API. After enabling this, encryption will work with no warnings and with a green lock bar.”

CA-signed also means “self-signed;” that is, an identity certificate is signed by the same entity whose identity it certifies. Regarding Tor, Igvi describes it as “ideal” for setting up Spark at home.

“Overall, I would say that my goal was to create a user-friendly wallet UI for using Lightning in day-to-day payments with the tools to make it easy for users to host their Lightning node at home under their full control and operating it remotely,” he says. “Integration of Spark into plug-and-play hardware solutions like the Casa Lightning Node would help make that even more accessible and is something I’m very interested in seeing develop.”