Sr. Backend Engineer

Job DescriptionJob DescriptionSr. Backend EngineerNashville, TN, or Santa Rosa Beach, FLResumes must be submitted in EnglishNo third-party recruiters, please!OMNICOMMANDERis 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 HereBe 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 ResponsibilitiesOwn 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 ForSenior-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 HolidaysPTO Days (Paid Time Off)PTO Day for your birthdayMedical InsuranceDental & Vision InsuranceCompany Paid Life Insurance401(k) Job Type: Full-timeA criminal background check is required.US work authorization is required.