DeFi Jobs

Location: Midtown, New York, NY and Singapore (In-office Mon–Thurs, Remote Fridays) Team: Payments Infrastructure – Mid, Senior, Staff, or Principal Levels

Company: Fun.xyz

Company Description
At Fun.xyz, we believe a tokenized future is a beneficial inevitability, granting financial emancipation to everyone with an internet connection. For a blockchain-first global economy to exist, value exchange must become intuitive, secure, and seamless.

Enter Checkout - the highest converting payment solution in web3. By integrating Checkout, dApps enable users to complete any on-chain action using crypto from a wallet, centralized exchange, or on-ramped fiat from a card or bank account. With access to market-leading routing and their asset portfolio at the point of sale, users are faster, stickier, and more engaged. For dApps, Checkout scales their user acquisition potential without launching new chains or integrating multiple third party providers.

We built Checkout because we envision a world where anyone, anywhere, can purchase anything with any asset. If that sounds like a vision you can get behind, we want to hear from you.

About The Role
We’re looking for a BackEnd Engineer to join our growing team at Fun.xyz and help architect the backend services that power our web3 payments infrastructure. This role is foundational to the success of our platform and will shape how payments, settlement, and transaction routing are handled across chains and payment providers. You’ll be working on high-performance, low-latency systems that support complex use cases like asset conversion, identity and security verification, transaction finality, and decentralized routing—while ensuring fault tolerance, scalability, and compliance across a global user base.

What You’ll Do

• Design and Scale Core Infrastructure: Architect robust backend services that power our Checkout engine and crypto SDK integrations
• Implement Secure, Reliable APIs: Build internal and external APIs for wallet management, payments orchestration, and token conversion across off-chain networks
• Integrate with Blockchains and External Systems: Collaborate with protocol and web3 partners to securely integrate on-chain actions, while also bridging to fiat and off-chain providers like CEXs, banks, and KYC vendors
• Own Transaction Lifecycle Logic: Handle everything from initiation to settlement, including multi-party transaction signing, auditing, and reconciliation.
• Enable Developer Success: Work closely with SDK and frontend teams to build abstractions that make integrating FunKit seamless.
• Design for High Throughput: Support hundreds of transactions per second with graceful degradation and global redundancy.
• Support Regulatory & Compliance Needs: Build infrastructure that supports KYC/AML, data retention policies, and auditability requirements
• Mentor and Collaborate: Lead by example in code quality, technical design, and engineering best practices
  
  
  
  

Required Skills And Qualifications

• Bachelor’s or Master’s in Computer Science, Engineering, or a related field. Equivalent professional experience is acceptable
• 4+ years of experience building and deploying distributed backend systems
• Deep experience with backend languages, Node.js, TypeScript is preferred
• Experience with monitoring and log management tools such as Prometheus, Grafana, CloudWatch, ELK Stack, or Splunk
• Experience with system networking, including aspects like TCP/IP, DNS, load balancing, VPN, VPC, subnetting, and routing protocols
• Experience working with various database systems like MySQL, PostgreSQL, or DynamoDB.
• Experience using infrastructure-as-code tools like Terraform, CloudFormation, or AWS CDK
• Ability to write, test, and debug smart contracts
• Familiarity with DeFi protocols and NFT standards
• Proficiency in writing automated tests for smart contracts
• Experience working in high-throughput, low-latency environments
• Excellent communication and collaboration skills across cross-functional teams
• Strong understanding of system design, caching, data modeling, and error handling
  
  
  
  

Nice To Have (But Not Required)

• Exposure to web3 technologies, including Ethereum, EVM-compatible chains, smart contract interaction
• Experience working with crypto custody providers, decentralized wallets, or key management tools (e.g., Fireblocks, Gnosis Safe, MPC wallets)
• Previous work on payment gateways, crypto exchanges, or DeFi protocols
• Familiarity with chain abstraction layers or bridges (e.g., LayerZero, Wormhole, etc.)
• Knowledge of blockchain data indexing or transaction reconciliation
• Contributions to open-source infrastructure or developer tools
  
  
  
  

What Sets You Apart

• You take ownership and accountability seriously
• You build systems with long-term maintainability and performance in mind.
• You thrive in environments that require both speed and rigor
• You are naturally curious about emerging technology and new paradigms.
• You think deeply about reliability, security, and system tradeoffs.
• You want to make a real-world impact by helping people transact with freedom and ease
  
  
  
  

Why Join Us

• Shape the future of payments and programmable money
• Work with bleeding-edge tech in a domain where innovation moves fast
• Join a mission-driven team focused on access, openness, and trust
• Be a key contributor, not just a cog—your work will ship fast and matter
• Collaborate with top-tier protocols, builders, and financial infrastructure providers
  
  
  
  

Location and Work Environment This role is primarily in-person at our Midtown, NYC headquarters. We work together Monday through Thursday for fast, iterative collaboration and optional WFH Fridays to reset and recharge.