Backend Engineer, Solving

Delphiventures; United States; Remote; USD 180,000 - 240,000; Full time

Job summary

Relay is seeking a Solving Engineer to own the software that generates quotes, routes trades across on-chain and off-chain venues, and fills user requests end-to-end. This high-impact role directly affects fill success, latency, and profitability of Relay’s solver business.

You will design and iterate the core pricing engine, build integrations with DEXs and aggregators, and develop observability and reliability tooling to support a robust, scalable platform that enables fast, low-cost

Qualifications

• Strong TS/Node.js backend experience.
• Experience with DeFi protocols and on-chain data.
• Ability to own multi-stage pipelines from data to execution.

Responsibilities

• Design and iterate on the solver's core quote-generation and pricing engine.
• Build integrations with DEXs and aggregators for swap routing.
• Develop observability tooling and reliable error handling.
• Collaborate to integrate settlement primitives and protocol-backed liquidity.
• Develop features for cross-chain payments use cases.

Skills

TypeScript / Node.js

On-chain protocols

DeFi primitives

High-availability systems

Tools

BullMQ

Redis

Datadog

Job description

About us

Relay is a cross-chain payments protocol that provides instant, low-cost cross-chain bridging, swaps, and transactions. We're the fastest and cheapest way to bridge and transact across chains, serving over 5 million users who have completed 59+ million transactions with $6+ billion in volume across 85+ chains.

Our company mission is to make transacting across chains as fast, cheap, and reliable as online payments. We are building the core infrastructure to abstract chains from end user payments, enabling the next billion users to experience the benefits of blockchain without the UX burdens.

About the role

The Solving team is the engine behind Relay’s ability to execute requests with the best price and highest reliability. As a Solving Engineer, you will build and own the software that generates quotes, routes trades across on-chain and off-chain venues, and fills user requests end-to-end. This is a high-impact, high-ownership role: your work directly affects fill success rates, latency, and the profitability of Relay’s solver business.

What you'll do

• Design and iterate on the solver’s core quote-generation and pricing engine, including on-chain price feeds, swap routing (1inch, LiFi, Uniswap), and dynamic fee calculation.

• Build integrations with DEXs and aggregators — writing contract-level fill calldata, handling multi-hop routes, managing slippage and gas estimation.

• Build observability and reliability tooling: structured error propagation, Datadog alerting, and solver-alarms triage workflows.

• Collaborate with the Protocol team to integrate new settlement primitives and support the transition to decentralized, protocol-backed liquidity.

• Build custom features for payment use cases — like 1:1 stablecoins and fixed pricing on majors.

About you

• You have the ability to own complex, multi-stage pipelines (deposit detection → quote generation → fill execution → settlement).

• You have strong instincts around reliability: you write error-handling, add observability, and think through edge cases like swap failures, liquidity crises, and gas spikes

• You're comfortable with a high degree of ownership and autonomy; you drive work from idea to production

Skills and abilities

• Experience building systems that interact with on-chain protocols: querying DEX quotes, constructing swap calldata, handling transaction reverts and retries

• Strong TypeScript / Node.js backend engineering skills, most of the solver codebase is TypeScript-first

• Understanding of DeFi primitives: AMMs, liquidity pools, token routing, slippage, price impact, and MEV

Nice to have

• Experience with cross-chain bridging protocols or intent-based architectures

• Prior work on solver or market-making systems in a DeFi context

• Familiarity with Solana and Jupiter routing, or Bitcoin UTXO-based transactions

• Experience integrating with BullMQ, Redis-backed job queues, or similar async job infrastructure

• Track record shipping integrations with major DEX aggregators (1inch, LiFi, 0x, etc.)

What we offer

• Competitive base salary

• Equity package

• Comprehensive health benefits

• Unlimited PTO policy with encouraged minimum

• Remote-first culture with emphasis on collaboration, communication, and flexibility