Senior API Developer

Senior API Developer
Porto
Porto, Porto District, Portugal

Are you a passionate backend engineer ready to shape the future of Web3 finance? Join a pioneering team building
- facing APIs at enterprise scale, powering the next generation of digital asset and fintech innovations.

We're spearheading a new business division that empowers enterprises to leverage a
- tested,
- performance platform with deep liquidity, seamless 'Anything-to-Anything' capabilities, and integrations across dozens of blockchain networks. If you thrive on designing scalable, secure APIs for millions of users in a
- moving industry, this is your chance to own
- critical work from day one.

What You'll Be Doing (Your Day-to-Day Impact)

• Design and build robust,
  - facing REST APIs engineered for massive scale and multiple enterprise partners
• Make key architectural decisions while migrating from monolith to microservices
• Develop
  - quality, performant code (primarily Node. js/Type
  Script, with some Go exposure)
• Own the full lifecycle of API features — from design and implementation to deployment, monitoring, and
  - call support
• Create
  - tier API documentation and interfaces that external developers love to use
• Collaborate closely with product, architects, and stakeholders across planning, design, and delivery
• Tackle
  - world challenges: payment widget integrations,
  - volume onboarding, SOC compliance, idempotency, versioning, and security at scale

Must-Have Skills & Experience

• 5+ years building Saa
  S or API-driven applications (public APIs in fintech/banking a strong plus)
• Expert-level Node. js (Java
  Script/Type
  Script) +
  - on Postgre
  SQL
• Proven experience designing & delivering highly scalable REST APIs (Graph
  QL bonus)
• Solid understanding of core API principles: security, versioning, idempotency, traffic monitoring, gateways & tools (Postman, etc. )
• Hands-on with microservices, Docker, and Kubernetes
• Strong relational database skills (Postgre
  SQL preferred) + familiarity with
  - relational (Redis/Valkey)
• Excellent English communication — you'll collaborate across teams and document for external audiences

Nice-to-Haves That Will Make You Stand Out

• Experience with financial services APIs, payments, Web3/crypto/digital assets
• Go language exposure
• Familiarity with AWS, Data
  Dog, Sentry, Cloudflare, Pager
  Duty
• Open-source contributions, blog posts, talks, or certifications

If you're a senior backend talent in Portugal who values speed without sacrificing quality, enterprise challenges, and building for the future of finance — we want to hear from you!

Apply now and let's build the gateway to Web3 together