Senior Software Engineer, API Products

At 0x, our mission is to "Create a Tokenized World Where All Forms of Value Can Flow Freely". We deliver this to web3 builders with a delightfully simple suite of developer APIs that provide faster trading, better prices, and superior user experience.

Founded in 2017, we’ve processed over 211M+ transactions and $180B+ in trading volume from users trading on Matcha, Coinbase Wallet, Robinhood Wallet, Phantom, Rainbow, Defi Llama, Meta Mask, Zerion, Zapper, and many more. Our investors include Greylock Partners, Pantera Capital, and Jump Crypto.

When you join 0x, you’ll become part of a veteran team of crypto builders who know the importance of code quality, team cohesion, and a culture of learning.

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.

Remote, EU timezones preferred.

• 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.

• 7+ years of backend engineering experience, including at least 2 years in De Fi 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.

• Experience with cross‑chain/bridging, or DEX aggregation.
• Experience with other ecosystems outside of EVM such as Solana.
• Experience with Type Script and/or Rust, our main languages.

• The base salary range for this position is USD $150,000 - $230,000 + equity + ZRX tokens + benefits. Within the range, individual pay is determined by job‑related skills, experience, location, business needs, and candidate preferences between the different compensation elements.

• Comprehensive insurance…