Nomad is a novel approach to blockchain interoperability that leverages an optimistic mechanism to increase the security of cross-chain communication. Using Nomad, developers can securely build cross-chain applications (or xApps) and bridge assets between chains. Nomad channels and the flagship xApp, the Nomad token bridge, are live on Ethereum and Moonbeam, with more chains coming soon.
While designing Nomad, we found ourselves presented frequently with difficult design decisions. Interoperability is a complex field, to say the least, and bringing a novel protocol to market required thinking deeply about the design space.
What we found through connecting the dots backward is that there is a consistent philosophy that informs Nomad’s design. Specifically, there are three core tenets that our decisions anchor to. By leaning on this backbone anytime we encountered a hard decision, we ensured that we developed Nomad in a way that adhered to our values and prioritized delivery over yak shaving.
We thought that these tenets could be useful for other teams working on gnarly problems, and could serve as a guidepost the way it does for us. Without further ado, the three tenets behind Nomad:
Users Over Systems
Tech matters. Users matter most.
The ability to build solutions to problems that real people experience is what gets us out of bed in the morning. Prioritizing the system can easily distract us from providing great products users want. System design should serve this end; it is not the end itself.
- We value human-facing utility more than interesting primitives.
- If we must choose between applications and mechanisms, we choose applications.
- Our success is measured in the wild, not in the lab.
Simple Over Complex
Complexity is the death of innovation.
We strive to build solutions that are no more complex than they need to be. We avoid new cryptography, and love reusing others’ libraries. Interoperability is inherently complex. Our goal is to make it simple for any developer.
- We value approachable and maintainable code more than minimal code.
- If we must choose between documentation and optimization, we choose documentation.
- Our success is measured in the bazaar, not in the cathedral.
Safety Over Formalism
Real harm is more important than theoretical harm.
We strive to take advantage of every tool that protects users. We aim to minimize the probability and impact of security issues. Our security practices are informed by formal analysis, but not centered on it.
- We value the real-world safety of users and funds more than crypto-economic models.
- If we must choose between smart contract security and a new whitepaper, we choose smart contract security.
- Our success is measured in mainnet attacks, not arXiv attacks.
Applying our Worldview
These core tenets help us make day-to-day decisions as we build Nomad. They’re guideposts that help us confidently navigate difficult terrain. Even before we wrote them down, they informed the core design of the system. It’s easy to see their impact on the system design today:
Users Over Systems
Nomad is underpinned by a generalized cross-chain messaging protocol. However, the heart of our tech stack isn’t the networking layer, it’s the applications that Nomad channels enable.
In order to build applications, we designed the Router pattern. Routers enable quick, secure development of xApps that can use any cross-chain channel, allowing us to rapidly iterate on the Nomad Bridge and our cross-chain Governance xApp. These applications matter more than the underlying channels.
Simple Over Complex
Cross-chain messaging is an enormous problem space. There is no perfect, generalizable solution. For years, light clients have been the apex of cross-chain tech. These underpin IBC, the Near Rainbow Bridge, and tBTC. Light clients require deep expertise of proof of work and proof of stake implementations, and are not approachable to new devs.
Nomad’s design eschews light clients in favor of a message tree and fraud proof. As a result, developers do not need to be consensus experts to contribute to Nomad. We focus on making the internal processes approachable, and providing xApp developers a clear interface and obvious best practices for using it.
Safety Over Formalism
When we decided not to include light clients in Nomad’s design, we also gave up formal security. While this decision had tremendous benefits for simplicity and operating cost, we had to accept that Nomad would not be provably secure. Nomad is designed to be secure in practice.
Nomad’s core channel relies on fraud proofs and proof of publication to prevent channel failure. In addition, it allows users and application developers to delegate trust protectors, who can mitigate the harm of fraud. In other words, Nomad’s system design chooses to provide safety via guard rails where it cannot provide provable security. We believe that this is the only choice that achieves our goals.
There Are No Solutions, Only Trade-offs
These tenets are not universal truths, and we respect other viewpoints. We believe in the power of formalism and system design, and we understand that complexity can be necessary to achieve goals.
We use these tools to improve our products whenever we can. Unfortunately, in the real world, tradeoffs sometimes must be made; we can’t always have our cake and eat it too. The Nomad design tenets guide us through complex decisions when sacrifices must be made, and they are the metrics by which we will measure our success.
We invite you to come along with us on this journey to a cross-chain future, we’d love to hear from you in our Discord and on Twitter. The Nomad team is working tirelessly to ensure we provide the best possible bridging experience, and we’re excited to see where this fledgling ecosystem goes in the next month, year, and beyond!
If you’re interested in seeing these tradeoffs in the wild, check out our GitHub, read the docs, and bridge some tokens.
