Apply on Employer Site

Toptal · 4 hours ago

Senior SQL Developer

New York, United States

Contract

Hybrid

Senior Level

Toptal is an exclusive network of the world’s top freelance professionals, and they are seeking a Senior SQL Developer to optimize and stabilize a high-volume SQL environment for a healthcare technology client. The role focuses on diagnosing slow-running queries, resolving locking issues, and improving overall system performance within a C#/.NET and Angular application stack.

CopywritingHuman ResourcesProduct DesignSaaSSoftwareSoftware Engineering

No H1B

U.S. Citizen Only

Responsibilities

Conduct a full performance audit of existing SQL queries, stored procedures, and reporting pipelines

Optimize slow-performing queries, multi-table joins, window functions, and EF-generated SQL

Diagnose and resolve locking, blocking, and deadlock conditions

Improve indexing strategy, query plans, and concurrency handling

Optimize Entity Framework usage patterns and reduce unnecessary DB roundtrips

Review and optimize SQL interactions within API calls and background jobs

Implement monitoring to track query health, performance regressions, and long-running jobs

Provide documentation and knowledge transfer to internal engineering leadership

Qualification

SQL optimizationC#/.NET performance tuningEntity FrameworkConcurrency patternsStored procedures tuningSQL performance toolsKnowledge transferBackground job processingHigh-concurrency systemsDocumentation

Required

Expert-level SQL skills with proven experience optimizing complex queries at scale

Strong experience with locks, blocking, deadlocks, and concurrency patterns

Hands-on experience tuning stored procedures, CTEs, and window functions

Experience with C#/.NET and Entity Framework performance tuning

Familiarity with high-concurrency systems and background job processing

Experience working with SQL performance tools (Query Store, Profiler, Execution Plans)

Preferred

Experience optimizing large reporting workloads

Familiarity with Angular-based frontend environments

Experience scaling systems with thousands of concurrent users

Experience with ETL pipelines or job schedulers in .NET ecosystems

Company

Toptal

Glassdoor3.8

Toptal is a network of talent in business, design, and technology that enables companies to scale their teams, on demand.

Founded in 2010

San Francisco, California, USA

1001-5000 employees

https://www.toptal.com

Funding

Current Stage

Late Stage

Total Funding

unknown

2012-07-01Seed

Leadership Team

Taso Du Val

CEO

Alejandro Rigatuso

Principal Growth Marketing Strategist

Recent News

Business Wire

Toptal Announces the Acquisition of Graphite

2026-01-07

Tech Times

BruntWork's 220% Pandemic Surge Sets Up A 45% FY25 Growth Trajectory

2025-10-25

Business Insider

This CEO says companies are getting hybrid wrong. It's not about mandating days in the office, he says.

2025-10-23

Company data provided by crunchbase