Blackbird Flynet Explained: Building the Rollup to Transform Restaurant Loyalty

“All we have is infra.”

“Why do we need another L2?”

“Where are the apps?”

Everyone in the Ethereum ecosystem has heard this sentiment: While we’ve built powerful infrastructure, we don’t have any apps that normal, everyday people would want to use.

The recent launch of Flynet is a direct response to that challenge. Flynet is the new rollup powering Blackbird, an onchain restaurant loyalty and payments company that saves restaurants money on credit card fees, gives users control of their restaurant data, and rewards them with $FLY points (aka tokens) they can use to buy meals – real meals, at real restaurants, in the real world. 

The best part is that Blackbird looks like a sleek web2 app. All the “crypto stuff” happens under the surface, but nonetheless provides utility restaurants and users couldn’t get otherwise. And the Flynet is at the center. Keep reading to learn how Conduit worked with the Blackbird team to build a high-performance rollup capable of putting Blackbird users’ restaurant activity onchain.

The Blackbird vision: Putting the restaurant experience onchain

Blackbird fills two core functionalities, both of which happen onchain:

• Check-ins that earn users $FLY they can put toward meals
• Payments

There are plenty of restaurant loyalty apps in the web2 world that have similar functionalities. But Blackbird saw an opportunity to better serve both restaurants and patrons by moving those functionalities and the data they generate onchain, and out of the centralized databases and closed systems where they currently sit. 

We spoke to Blackbird Lead Engineer Jeff Blanchette to learn more about the vision. “There are straightforward benefits like lowering payment fees for restaurants, and rewarding customers with a token they can spend on future meals.” Both of these are important. Credit cards charge 3.75% or more in fees, while Blackbird takes just 2% – crucial savings in a low-margin industry like dining. And of course, what user wouldn’t want free restaurant cash?

But there are other benefits as well. By memorializing every restaurant experience onchain, Blackbird allows users to take control of their data and turn it into a decentralized identity they can bring with them to new restaurants. Imagine you had to move to a new city tomorrow and leave your favorite restaurants behind. With Blackbird, you could choose to share your dining history with restaurants in the new city so that they know how to tailor the experience to you – your favorite drink, where you like to sit, how you like your steak, and so on.

“There’s so much value in the contributions customers make to restaurants, not just in foot traffic, but through their presence, personality, and experiences," said Jeff. "With Blackbird, customers can own their dining history, keep it in their Blackbird wallet, and use it to enhance future hospitality experiences."

Building Flynet: The why and how behind a custom rollup

Scalability and transaction costs are a major challenge for any onchain consumer app that’s growing quickly. Every restaurant interaction users have through Blackbird is posted to the chain as a transaction, along with another transaction rewarding users for those interactions. An L3 rollup was the only way to process all that data while still maintaining user experience. “You never have to worry about whether your bill is settled – it’s all happening in real time, and costing you less than a fraction of a cent,” said Jeff. 

Launching on a rollup also allowed the Blackbird team to partner with a platform like Conduit, who could handle the infrastructure and enable the team to put all their energy into making Blackbird the best app possible. “Conduit had everything we needed right out of the box – block explorer, bridge, a great interface. And the platform made it really simple for us to set up a testnet and tinker with it to make sure everything worked,” said Jeff.

Once Blackbird confirmed Conduit was the right platform to launch Flynet, our teams began working together to build it.

Flynet infra choices: Optimizing for performance and community with Arbitrum and Base

After investigating both OP Stack and Arbitrum Orbit, Blackbird decided to build Flynet on Arbitrum, largely due to its performance and customizability. “Arbitrum has really low block times, which means we can settle transactions faster. And it has a high-performance custom EVM language we plan to utilize,” said Jeff. 

Another big point in Arbitrum’s favor was its support for custom gas tokens – in Flynet’s case, the $F2 token. “We really wanted to avoid users needing to seed their wallet with ETH to use Blackbird – it’s bad UX,” said Jeff. But $F2 will do even more than that. “$FLY is essentially a stablecoin that’s only meant for restaurant payments. $F2 is what we’ll use to reward users and incentivize developers to build on Flynet,” he explained.

Jeff pointed to Conduit’s expertise as essential in managing the difficulties that come with a custom gas token. “Custom gas tokens behave a bit differently. It’s complex to have your chain’s native token powered by smart contracts on another chain,” said Jeff. “Conduit has been excellent about getting into the weeds with us on how to manage that and making sure we don’t make any mistakes.” 

Meanwhile, Blackbird chose Base as its settlement layer because of its ability to draw on both great builders and a large community of users. “Base has a huge builder ecosystem that can really enrich Flynet,” said Jeff. “We want those builders to put products on Flynet, or enhance their products with Blackbird data. And the ability to onboard users from Coinbase is huge.” 

Customizing the chain

Once Blackbird made its core infrastructure choices, Conduit worked with the team to customize the chain further to meet Blackbird’s exact needs. “We had a strong, specific understanding of what Flynet needs to be, and Conduit was the only team who could give us that without any real difficulty,” said Jeff. For example, Conduit helped Blackbird set custom fees at the sequencer level to ensure that the chain is always cheap for users, and also worked to ensure no assets were bridged to Flynet early, helping Blackbird maintain regulatory compliance. 

Conduit also helped Blackbird set access restrictions at the sequencer level so that they could control who builds on Flynet early on, before allowing more developers in the future. “We can’t risk our users’ trust by letting unvetted developers build potentially scammy apps on Flynet,” said Jeff. “That would be game over. Conduit helped us set up the sequencer so that we can start with first-party apps, then open access to more devs later.” 

Wallet infrastructure and account abstraction for top-tier UX

One of Blackbird’s strongest attributes is its UX. The team is utilizing the latest account abstraction and MPC wallet infrastructure to give the app an intuitive, web2-like interface for users.

One key partner here is Privy. Users can sign up for Blackbird with just a phone number and email, and Privy creates their wallet in the background. Users don’t even need to learn their wallet address unless they want to deposit crypto to it themselves. “Privy is totally embedded into the application, and we can put our UX right on top of it with zero restrictions,” said Jeff.

Privy’s also enables users to recover their account if they lose their private key, and makes it possible for users to simply pay for meals in one screen tap, without having to input the bill amount or receiving wallet address. “Users just give us permission from the wallet, and we do everything in the background,” said Jeff.

What’s next for Blackbird and Flynet?

Blackbird is pioneering a new model for restaurant loyalty and payments, and showing the crypto industry what a real world onchain app looks like. Already, more than 100,000 wallets hold $FLY, with each of those wallets averaging 6.2 transactions – the traction is clearly there. 

The story of how Blackbird built Flynet highlights a key benefit of rollups: Customizability. A team can build a chain from the ground up for their own unique use case, while still tapping into the decentralization and community of the larger but less flexible L1 at the bottom of the stack. It also shows how choosing the right onchain infrastructure – even infrastructure that runs under the hood – ultimately enables the UX that users want. 

“Our team, especially our CEO Ben Leventhal and Crypto Product Lead Jake Schlessinger, had an amazing vision for Blackbird and executed on it so well,” said Jeff. “Partners like Conduit, Arbitrum, Base, and Privy were essential.”