Senior Full-Stack Developer (C# + AWS)

The Role:

The Senior Full-Stack Developer owns delivery of roadmap features set by our executives. Working hands-on under the guidance of the technical cofounder and alongside a small team of senior engineers, this person will architect, build, and operate cloud-native services without day-to-day micromanagement.

Key Responsibilities:

• Design, develop, and maintain scalable microservices and web applications using C#/.NET Core
• Architect, deploy, and optimize workloads on AWS (EC2, ECS Fargate, Lambda, RDS, DynamoDB, S3, CloudFormation or AWS CDK)
• Drive all phases of the software lifecycle: technical design, implementation, testing, monitoring, and continuous improvement
• Participate in peer code reviews and help uphold high engineering standards
• Identify and implement platform improvements that enhance performance, reliability, security, and developer experience
• Collaborate with Product, Support, and QA to release customer-facing features and resolve production issues promptly

Required Qualifications:

• 8+ years of professional software development, including 5+ years with C#/.NET Core or later
• Demonstrated success building and operating full-stack applications on AWS
• Strong knowledge of relational and NoSQL data modeling
• Proven ability to work autonomously, take accountability for outcomes, and deliver high-quality solutions
• Excellent written and verbal communication skills with a bias for action and clarity

Bonus Qualifications (VoIP & Real-Time Communications):

• Hands-on experience with one or more of the following:
  • Asterisk or FreeSWITCH
  • SIP, RTP, and media negotiation
  • Kamailio or OpenSIPS
  • WebRTC data or media channels
• Experience designing, scaling, and troubleshooting VoIP workloads on AWS, including NAT traversal and global media routing
• Familiarity with audio codecs, QoS, and diagnostic tools such as sngrep and Wireshark

Working Practices & Culture:

• Time-zone overlap – minimum of three overlapping hours with teammates in Europe or US Eastern time for real-time collaboration
• Autonomy with guidance – goals are set with the technical cofounder and CEO; the developer chooses the best execution approach
• Continuous delivery – small, frequent deployments supported by automated tests and infrastructure as code
• Ownership mindset – every engineer can improve the product, codebase, and processes