Senior SW Developer / Financial SaaS

A client within the financial software sector is looking for a senior software developer to join their project team short-term. You'll be working on software development tasks, using AI tools like Claude to support your daily coding work. Work will be conducted under NDA (Non-Disclosure Agreement).

Start: ASAP (October 2026)

Duration: Until 31.12.2026

Location: Mostly remote, occasional visits to Helsinki or Lappeenranta office

Language: English

Allocation: 100%

We're looking for:

• Proficiency in C# and .NET (.NET 10)
• Experience with relational databases like PostgreSQL or SQL Server
• Competence in writing and maintaining tests, with experience in Playwright, xUnit, or Moq
• Daily hands-on use of AI coding agents like Claude Code or GitHub Copilot, plus the judgment to review AI-generated code
• Security practices including SAST, dependency scanning, and secret hygiene
• A proactive, team-player mindset with effective communication skills

Beneficial:

• Experience with complex integrations and data migrations
• Experience with REST and XML/SOAP APIs, OAuth2, API keys, and webhooks with signature validation
• AWS experience, including Lambda, ECR, API Gateway, and Secrets Manager
• Familiarity with CI/CD pipelines, Git, and GitHub Actions
• Infrastructure as code using Terraform and database migrations
• Experience handling integration challenges like idempotency, retries, partial failure, rate limits, and reconciliation
• Experience writing custom AI tools, agent skills, subagents, or MCP servers

Interested? Please contact Lisa_Witted in Slack or lisa.teutari@witted.com