Sr. Backend Engineer

Job Description

Job Description

Sr. Backend Engineer

Nashville, TN, or Santa Rosa Beach, FL

Resumes must be submitted in English

No third-party recruiters, please!

OMNICOMMANDER is a fast-growing fintech company and three-time Inc. 5000 honoree. We lead the industry in digital branches and marketing, giving financial institutions a single platform to create, host, and manage their digital branch. We have offices in Tennessee, Florida, and Bogotá, Colombia. This is an on-site role based in Brentwood, TN, or Santa Rosa Beach, FL.

We are hiring a senior backend engineer to design, build, and operate cloud-hosted services for financial institutions. This is a hands-on role focused on C#/.NET, PostgreSQL, and AWS. You will build secure, multi-tenant software, guide technical decisions, and mentor teammates while staying close to the code. This role reports to the Software Engineering Manager.

Why You’ll Love Working Here

• Be part of a fast-growing fintech company with a fun, supportive culture.

• Work in a dynamic, high-tech environment with hands-on experience working with AI.

• Competitive pay and comprehensive benefits, including paid holidays, PTO, an additional day of birthday PTO, company-paid life insurance, and 401(k) with employer match.

• Global team with offices in Tennessee, Florida, and Bogotá, Colombia.

Key Responsibilities

• Own the design, implementation, maintenance, and evolution of REST APIs and backend services using C#, ASP.NET Core, and Entity Framework Core.

• Design PostgreSQL schemas and migrations; improve data access, query performance, transactions, and concurrency behavior.

• Build and support workloads on AWS using Docker, ECS/Fargate, Lambda, S3, SQS, and related services as appropriate.

• Engineer secure authentication and authorization, including JWT/OIDC, role-based access controls, least-privilege permissions, and strict tenant isolation.

• Implement resilient asynchronous workflows and integrations for assets, notifications, publishing, and other platform operations.

• Deliver well-tested code through unit and integration tests, GitHub pull requests, CI/CD pipelines, and safe deployment and rollback practices.

• Investigate production defects and performance issues; use logs and operational evidence to identify root causes and prevent recurrence.

• Collaborate with Product, QA, Design, and engineering peers; review designs, mentor teammates, and communicate tradeoffs clearly.

• Strengthen secure development practices, documentation, audit trails, and repeatable controls that support SOC 2 readiness.

What We Are Looking For

• Senior-level engineering experience, 6+ years or equivalent demonstrated expertise, with substantial ownership of production backend systems.

• Advanced C# and ASP.NET Core experience, including modern .NET, asynchronous programming, dependency injection, API design, error handling, and maintainable architecture.

• Strong hands-on PostgreSQL and Entity Framework Core skills, including schema evolution, query optimization, data integrity, and safe migrations.

• Practical AWS production experience, including containerized workloads, IAM, service configuration, monitoring, and troubleshooting.

• Experience building secure, multi-tenant SaaS applications and implementing authentication, authorization, and defense-in-depth protections.

• Evidence of automated testing, Git-based code review, CI/CD ownership, and debugging complex production issues.

• Strong written and verbal English communication (B2 level or higher), sound technical judgment, and experience mentoring engineers.

• Experience working with Terraform or other infrastructure-as-code tools; AWS CloudFront, Secrets Manager, KMS, WAF, or Step Functions is a plus.

• Experience with SignalR/WebSockets, Redis, DynamoDB, event-driven systems, or advanced observability is a plus.

• Experience with Python or Rust for supporting services; Amazon Bedrock, AI integrations, or vector search is a plus.

• Fintech or enterprise SaaS experience, secure SDLC practices, and familiarity with SOC 2-oriented evidence and controls are highly desirable for this role.

Benefits: (waiting period may apply)

• Company Paid Holidays

• PTO Days (Paid Time Off)

• PTO Day for your birthday

• Medical Insurance

• Dental & Vision Insurance

• Company Paid Life Insurance

• 401(k)

Job Type: Full-time

A criminal background check is required.

US work authorization is required.