Senior Software Engineer, 0x

• 7+ years of backend engineering experience, including at least 2 years in DeFi at a trading app, wallet, DEX aggregator, onchain data company or similar
• Senior or Lead Engineer with a track record of owning complex projects end to end
• Built and maintained developer-facing APIs
• Deep onchain knowledge, especially EVM: how transactions work, including calldata, contract interfaces, gas and approvals
• Strong system design experience for production-scale backend services
• You’re an AI power user who uses it to multiply your impact as an engineer, yet you don’t let it replace your judgment
• Clear communicator, comfortable explaining technical tradeoffs to non-engineers
• Aligned with our core values: do the right thing, consistently ship, and focus on long-term impact
• Able to attend annual in-person team offsites around the globe

Desirable

• Behind every 0x trade is a lot of hard work. We integrate hundreds of liquidity sources, optimize for gas, slippage and latency, split routes and simulate every result to get traders the best possible outcome
• The API Products team turns that routing logic into easy-to-integrate APIs that wallets, exchanges, trading apps, bridges and developers around the world rely on
• This team of four built, maintains and continues to evolve our flagship Swap, Gasless and Cross-Chain APIs, which have moved billions in volume. Next, they’re building new products that give developers even more tools for building trading apps
• We’re hiring a Senior Software Engineer to expand what the API Products team can take on
• You’ll lead projects from first idea to production, on new products and on the APIs that are already live, working closely with our product team and some of our biggest customers
• This is a hands-on IC role for someone who wants real ownership and works well with little direction
• Build new APIs and trading products, from researching the problem and designing the architecture to shipping the first version
• Maintain and extend our existing APIs, including support for new chains, bridges and customer-requested features
• Keep our APIs fast and reliable as traffic grows, and participate in the on-call rotation
• Investigate failed trades and stuck transfers using logs, traces and onchain data, and resolve the root cause
• Work with product, legal and GTM, turning business and compliance needs into technical decisions
• Write design documents for your work and review your teammates’ designs and pull requests