Backend Engineer

**Fun.xyz** Backend Engineer (Mid–Staff); SGD 120–300k across L1–L4 + equity; Singapore (open to relocation and visa sponsorship)

**About Company** Fun.xyz builds crypto payment infrastructure that makes onchain value transfer intuitive, secure, and seamless for everyday users and developers. Its flagship product, Checkout, is a high-conversion payment solution that lets users complete any onchain action using assets from self‑custodial wallets, centralized exchanges, or on-ramped fiat from cards and bank accounts. By aggregating routing and exposing users’ full asset portfolios at the point of sale, Checkout helps dApps drive faster, stickier, more engaged users without stitching together multiple providers or spinning up new chains. If you believe anyone, anywhere should be able to purchase anything with any asset, Fun.xyz is a place to build that future.

**About the Role** The Backend Engineering team designs and operates the high-performance systems that power Checkout and Fun.xyz’s broader payments stack. Backend Engineers architect APIs, services, and distributed systems that handle payments, settlement, asset conversion, identity/security verification, and multi-chain transaction routing. This is a foundational role in building fault-tolerant, low-latency infrastructure that can scale globally while meeting security and compliance expectations. You will report into the CTO (ex-Hyperlane, ex-Uniswap) and work closely with product engineers and protocol engineers.

**Responsibilities** - Design, build, and maintain high-performance APIs and backend services for Fun.xyz’s Web3 payments platform. - Implement and evolve systems for payments, settlement, transaction routing, asset conversion, and identity/security flows across chains and providers. - Build new backend features that improve product experience, conversion, and reliability for dApps and partners. - Participate in system design, architecture reviews, and incident response to ensure reliability, scalability, and fault tolerance. - Write clean, well-tested code and contribute to code reviews and engineering standards.

**Required Skills** A. Strong experience building production backend systems in a modern language (TypeScript preferred; Go or Rust acceptable for strong system engineers willing to work in TS). B. Proficiency with TypeScript or clear ability and motivation to ramp quickly (core stack). C. Deep understanding of distributed systems, APIs, and database design principles. D. Hands-on experience with cloud platforms and containerization (e.g., Docker, Kubernetes, modern cloud infra). E. Solid CS fundamentals in algorithms, data structures, and systems design.

**Bonus Skills** - Experience in payments, fintech infrastructure, or transaction-heavy consumer apps. - Prior exposure to blockchain integrations, smart contracts, or DeFi protocols (not a hard requirement). - Familiarity with event-driven architectures and real-time data processing. - Contributions to open source or technical writing in backend, infra, or crypto domains.

**Logistical Info** - **Location:** Singapore (open to relocation and visa sponsorship) - **Compensation: **Fun.xyz targets roughly 75th percentile of market base comp with a broad band from ~120–300k SGD across L1–L4, with equity scaled by level; senior backend/EM profiles can approach the top end of the band (exact band confirmed per candidate level). - **Number of openings:** Up to 2

**Ideal Background** - Candidates from these schools (no exceptions): https://www.hkengage.gov.hk/en/how-to-apply-for-a-visa/admission-scheme-matching-tool-institutions - Backend/system engineers from high-scale fintechs, infra companies, or consumer apps with experience in payments, routing, or transactional systems. - Crypto/Web3 backend engineers with strong infra chops who can operate in TypeScript and distributed architectures. - Recruiter note: for big-tech / mega-corp backgrounds (TikTok, ByteDance, Shopee, Grab, Meta, etc.), include a 'why Fun.xyz' motivation blurb before the first call. **Green Flags** - Building something from zero vs. maintaining or optimizing existing systems - Candidates that can move fast with 'minimal scaffolding' (ideally from startups or fast teams where speed and ambiguity were the norm) - Gritty, hungry builders

**Red Flags** - Pure front-end profiles without substantial backend ownership. - Pure bank backgrounds (0% pass rate; deprioritizing entirely) - Strongly remote-only candidates unwilling to commit to in-office presence. - Shallow systems design or weak fundamentals, especially under time-boxed live coding. - Pure bank backgrounds (0% pass rate; deprioritizing entirely); Java isn't a disqualifier, but seeing correlation between Java and bank/finance backgrounds and failing their screen - Candidates with CEX backgrounds that were on 'slow teams' vs faster startup-esque teams (identify which teams candidates were on; do not submit based on logo alone) - Senior candidates (10-20 YoE) from banks who hopped to CEX

**Interview Process** 1. Recruiter screen with Recruiter 2. 1-hour live coding interview with CTO or senior backend engineer using a shared environment (e.g., CodeSandbox/HackerRank); candidates can choose language, but mainstream languages fare better. 3. Follow-up systems design / technical deep-dive. 4. Onsite for additional coding and technical interviews (~2 hours) plus potential founder chat.