Back-End Developer (Node.js / Microsoft SQL Server)

Flexi Software•Atlanta, GA

8d•Hybrid

About The Position

Flexi Software, a 30+ year-old enterprise software company, is building the next generation of its commercial accounting applications as a modern multi-tenant SaaS solution on Azure, while continuing to support on-premises deployments. This role is a core engineering hire for this re-platforming effort, based in the Atlanta office. The company's accounting logic is proven, and customers are live on the existing software, but the underlying technology is dated and expensive to maintain. The new platform aims to modernize the technology stack while ensuring the correctness and reliability that customers depend on for their financial operations.

Requirements

4–7 years of professional back-end development experience.
Strong Node.js skills, with production experience building REST APIs — NestJS, Express, or comparable.
Professional TypeScript experience. We expect working fluency with typed JavaScript (TypeScript) rather than a willingness to learn it.
Deep Microsoft SQL Server / T-SQL expertise: stored procedures, views, functions, triggers, transactions and isolation levels, indexing strategy, and query tuning from execution plans. SQL Server 2017 or newer.
Practical experience with concurrency in a high-volume OLTP system: transaction isolation levels, locking and blocking, deadlock diagnosis, and row-versioning approaches such as snapshot isolation. In an accounting system, a lost update is not a performance problem; it is a financial error.
Demonstrated ability to design and evolve relational schemas for transactional systems, including migrations against databases that are already in production.
Experience troubleshooting performance problems in high-volume data environments.
Solid grasp of API design fundamentals: versioning, authentication and authorization, error handling, and backward compatibility.
Comfort with Git and modern development workflow — branching, code review, CI.
Bachelor's degree in Computer Science, Engineering, or a related discipline, or equivalent practical experience.
Clear written and verbal communication: accurate status updates, early flagging of risk, and the judgment to raise a problem before it becomes a deadline.
Ability to own tasks through to completion without detailed supervision, and to estimate your own work realistically.

Nice To Haves

Experience in a professional environment using C# and the .NET stack.
Multi-tenant SaaS architecture experience, particularly tenant isolation and data-partitioning approaches.
Azure platform experience: Azure SQL Database, App Service, Azure DevOps.
Background in accounting, ERP, or financial software, or in any domain where data correctness is non-negotiable.
Experience with commercial software that ships to customers, as opposed to internal-only systems.
The Atlassian tool suite — Jira, Confluence, and Loom.
Reporting and analytics exposure — Microsoft Fabric, the umbrella Microsoft's data and analytics services are consolidating under, along with Power BI and Azure Synapse Analytics.

Responsibilities

Build API services: design, develop, test, and document RESTful services in TypeScript on Node.js (NestJS or Express).
Work across the data boundary: write and tune T-SQL, design and evolve schemas, and make deliberate case-by-case calls about whether business logic belongs in a stored procedure or in the service layer.
Carry legacy logic forward: read and understand existing legacy database code, and translate it into the new architecture without losing the accounting behavior our customers depend on.
Make it fast under real load: profile and optimize queries, indexes and API endpoints for concurrency and large data volumes; diagnose performance problems from execution plans and query statistics.
Build for multi-tenancy: implement tenant isolation, data partitioning and access patterns that hold up as the tenant count grows.
Support both deployment models: write code that works against Azure SQL Database in our cloud and Microsoft SQL Server in customer on-premises installations, and account for the differences between them.
Contribute to architecture: participate in design discussions for new functionality; on a team this size, mid-level engineers are expected to have a voice in the design, not just an assignment.
Fix what breaks: investigate and resolve defects surfaced through QA and customer support, including issues that only appear at customer data volumes.
Write the tests and the docs: unit and integration tests for the code you ship, and technical documentation your teammates can actually use.