Senior Backend Engineer - Fintech SaaS, AWS, C#/.NET

Omnicommander; Santa Rosa Beach (FL); On-site; USD 120,000 - 190,000; Full time

Benefits offered by this job

Company Paid Holidays

PTO Days (Paid Time Off)

Birthday PTO Day

Medical Insurance

Company Paid Life Insurance

401(k)

Job summary

Omnicommander is a fast-growing fintech company hiring a senior backend engineer to design, build, and operate cloud-hosted services for financial institutions. The role focuses on C#/.NET, PostgreSQL, and AWS, delivering secure, multi-tenant software.

You will mentor teammates, guide technical decisions, and work on REST APIs, data models, and scalable architectures, reporting to the Software Engineering Manager, with on-site work in Brentwood, TN or Santa Rosa Beach, FL.

Qualifications

• 6+ years of senior backend engineering experience with ownership of production systems.
• Advanced C# and ASP.NET Core experience, modern .NET, asynchronous programming and API design.
• Strong PostgreSQL and EF Core skills, including schema evolution and safe migrations.
• Practical AWS production experience with containerized workloads, IAM, monitoring, and troubleshooting.
• Experience building secure, multi-tenant SaaS applications with auth and SOC 2 considerations.
• Evidence of automated testing, Git-based code review, and CI/CD ownership.
• Excellent written and verbal English communication; mentoring experience welcome.
• Experience with Terraform or IaC tools; AWS services like CloudFront, Secrets Manager, KMS, WAF, or Step Functions is a plus.
• Experience with SignalR/WebSockets, Redis, DynamoDB, event-driven systems, or observability is a plus.
• Experience with Python or Rust for supporting services; AI integrations or vector search is a plus.

Responsibilities

• Own design, implementation, maintenance, and evolution of REST APIs and backend services using C#, ASP.NET Core, and EF Core.
• Design PostgreSQL schemas and migrations; optimize data access, queries, and concurrency.
• Build and support workloads on AWS using Docker, ECS/Fargate, Lambda, S3, SQS.
• Engineer secure authentication/authorization with JWT/OIDC, RBAC, least-privilege, and tenant isolation.
• Implement resilient asynchronous workflows and integrations for assets, notifications, and publishing.
• Deliver well-tested code through unit/integration tests, PRs, CI/CD, deployment and rollback practices.
• Investigate production defects and performance issues using logs and metrics to identify root causes.
• Collaborate with Product/QA/Design/Engineering; review designs and mentor teammates.
• Strengthen secure development practices, documentation, audit trails, and SOC 2 readiness.

Skills

C#

ASP.NET Core

PostgreSQL

AWS

Docker

SaaS architecture

Security best practices

CI/CD

Terraform

WebSockets / SignalR

Tools

Terraform

Redis

DynamoDB

Docker

KMS

SQS

ECS/Fargate

Job description

Omnicommander is a fast-growing fintech company hiring a senior backend engineer to design, build, and operate cloud-hosted services for financial institutions. The role focuses on C#/.NET, PostgreSQL, and AWS, delivering secure, multi-tenant software.

You will mentor teammates, guide technical decisions, and work on REST APIs, data models, and scalable architectures, reporting to the Software Engineering Manager, with on-site work in Brentwood, TN or Santa Rosa Beach, FL.