lightning network
Greenlight by Blockstream: Lightning Made Easy
July 21, 2021
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Today we’re excited to unveil Greenlight, our latest Lightning Network service. The new service provides simple, secure access to the Lightning Network, allowing anyone to spin up their Lightning node in the cloud while retaining complete control over their funds.

Getting started with Bitcoin can be challenging, particularly when learning how to keep funds safe and private. Onboarding Lightning adds another layer of complexity because of the need to operate channels and liquidity as well as manage backups and watchtowers. New users often opt for custodial services where these technical challenges are managed for them but at the cost of trusting the service operator with their funds.

There is, however, a middle ground that we think is far better: use an operator to run the node with all of the associated challenges while keeping control over the funds with the user. This is precisely what Greenlight enables. Based on the highly modular and extensible open-source c-lightning implementation, we can run the node on our infrastructure while the user retains the keys on their own user device. Anything that touches your private keys requires signing by your device.

Lightning Simplified

Greenlight allows anyone to boot up their personal Lightning node on our cloud infrastructure in seconds and take full control over their funds. The private keys, required to sign both on-chain and off-chain transactions, never leave the user’s device.

Users interact with the node via a simple programmable interface and we take care of the rest. We schedule the node on our infrastructure when needed, managing everything from the Bitcoin back-end to encrypted backups and watchtowers. You take care of your funds, we’ll manage the rest.

When scheduled to run on the infrastructure, the node will attempt to connect to the user’s device which holds the keys and ask for sign-off on any operation that involves the user’s funds. When the user isn’t using their node, it shuts down automatically until it’s needed again. Starting the node is almost instantaneous, ensuring that the user experience is seamless.

The key differences from other setups can be summed up by the following:

A Tool for App Developers

As we mentioned above, one aspect of Greenlight is its user-friendliness that caters to newbies in the space, supporting them as they start their Bitcoin journey. Another important aim of ours is to empower developers building Lightning-enabled apps to innovate without needing to become node operation experts in the process. To help actualize this goal we’ve been working with two very exciting companies—Sphinx and Lastbit.

Sphinx Chat is a browser for the Lightning Network, where you can send and receive sats, form encrypted chat groups, and stream podcasts. By downloading the sphinx-relay onto Raspberry Pi hardware and connecting it to the Greenlight server, users can spin up a node and begin chatting in a matter of seconds without the overhead of syncing with the blockchain, installing a Lightning node, or setting up the rest of the infrastructure.

Lastbit is a technology platform that provides low-cost, instant payments around the world through the Lightning Network. Lastbit utilizes Greenlight through its simple web interface, Striga, which allows visitors to the website to spin up their personal node on demand without having to run any of the infrastructure themselves.

Availability

We want to ensure that users have the best possible experience when using Greenlight. In order to guarantee this, we plan to incrementally grant access to new users as we scale up in a controlled manner. At the moment, we onboard new users through our launch partners, which helps us improve the service before opening up to everybody. If you’d like to participate in the early phase and test the service firsthand, let us know.

This is but the first step in our journey. Currently, the service provides c-lightning nodes on demand. Looking ahead, you can expect additional features, such as automatic proposing channels, rebalancing liquidity, swap services, and much, much more.

Greenlight is available through Sphinx and Lastbit (currently on testnet), with an incremental rollout planned for the greater public after the initial beta phase. We encourage interested users to try out Greenlight via Sphinx or Lastbit.

The Road Ahead

This is just the beginning, and we are committed to improving and extending Greenlight with new features, security and privacy improvements, as well as improvements to the accessibility of the service as we learn together with our partners.

Blockstream holds a strong belief in setting realistic goals and not overpromising. Honoring this tradition, we’d like to share some of the open research questions and planned features, and how we plan to tackle them:

We are a small team, and some of these will undoubtedly take time. If these challenges sound interesting to you, and you’d like to help make them a reality, we are always looking for talented engineers to join our ranks. Just send us a message.