Senior .NET Developer / Tech Lead

Project/Client:Fintech Location:Lithuania Start Date:ASAP Duration:12 months Language:English

Role Overview:

We’re looking for aSenior .NET Developer / Tech Leadto join our engineering team and build payment-focused backend solutions in a regulated fintech environment. This is a hands-on role combining software development with technical leadership. You’ll design and develop backend services, contribute to technical and architectural decisions, and help the team maintain high engineering standards.

Key Responsibilities:

• Design and develop backend services usingC# / modern .NET

• Contribute totechnical designandarchitectural decisions

• Build integrations withREST APIs, third-party platforms, messaging, and file-based interfaces

• Ensure code quality throughcode reviewsand engineering best practices

• Mentor developers and leadtechnical discussions

• Work withSQL, relational databases,CI/CD, andDocker

• Buildsecure, reliable, and scalablesoftware solutions

• Collaborate with product, compliance, QA, and other engineering teams

Must-Have Requirements:

• 7+ yearsof hands-onC# / .NETexperience

• Strongbackend developmentexperience

• Experience withREST APIs, integrations, anddistributed systems

• StrongSQLand relational database experience

• Experience withDockerandCI/CD

• Understanding ofsecure and reliable software development

• Experience as aSenior Engineer,Tech Lead, or similar

• Ability to taketechnical ownershipand guide other developers

Nice to Have:

• Experience inpayments,banking,fintech, orfinancial services

• Experience in aregulated / compliance-driven environment

• Knowledge ofISO 20022 / SEPA

• Understanding ofclearing,settlement, orpayment processing

• Experience withAzureorAWS

• What we offer

  • Model: B2B contract with Bonapolia - one contract, one monthly invoice

  • Rate: negotiated per candidate seniority and client budget

  • Payment: monthly invoice, paid on the same schedule the client pays us (usually 30 days)

  • Contract written under your country's law

  • We handle the client-side paperwork: MSA, NDA, invoicing

  🏢 About Bonapolia

  Bonapolia is a family-owned IT staff augmentation team based in Lisbon. We build engineering teams for product companies and IT consultancies across Europe and the US.

  More at 📩 Ready to Join? We look forward to receiving your application and welcoming you to our team!

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