Sr. Software Engineer (.NET Core & API Integration)

Boomtown Accelerators; Leesburg (VA); On-site; USD 120,000 - 170,000; Full time

Benefits offered by this job

Competitive benefits package

Growth opportunities

Collaborative team culture

Job summary

ThrivePass is seeking a Sr Software Engineer with expertise in .NET Core & API integration to build, maintain, and enhance scalable web applications. You will work with cross-functional teams to deliver high-quality software, focusing on performance, security, and maintainability.

Ideal candidates have 4+ years of backend experience in API-heavy environments, strong data modeling skills, and a passion for designing resilient integrations with REST, GraphQL, and event-driven patterns.

Qualifications

• 4+ years backend engineering in API-heavy environments.
• Reverse-engineer poorly documented APIs and map complex payloads.
• Data modeling and abstraction design expertise.
• REST, GraphQL, and event-driven integrations experience.
• Integration middleware, API gateways, and webhooks knowledge.
• Async processing, queues, and retry strategies familiarity.
• Strong problem-solving for edge cases and schema drift.

Responsibilities

• Analyze, map complex APIs into normalized data models.
• Design and build connectors/integrations for SaaS platforms and vendor APIs.
• Develop data transformation pipelines and normalization layers.
• Handle authentication and authorization across providers (OAuth2, API keys, SAML, custom).
• Build resilient integration patterns against rate limits and errors.
• Collaborate with product teams to design unified API schemas.
• Establish testing, monitoring, and logging frameworks for reliability.
• Mentor engineers on integration architecture and abstraction.

Skills

API integration

Data modeling

REST

GraphQL

Event-driven architecture

Middleware & gateways

Async processing

Tools

OpenAPI

JSON Schema

Job description

Who We Are

At ThrivePass, we’re on a mission to help employees and businesses Thrive—because benefits should be more than just checkboxes. Through personalized benefits technology, data-driven insights, and meaningful experiences, we empower companies to support their teams in ways that truly matter.

We don’t just talk about culture—we build it. Everything we do is rooted in our CARE values:

• Courageous – We embrace new challenges and fresh ideas.
• Authentic – We show up as our true selves and value transparency.
• Resourceful – We find creative solutions and make things happen.
• Excellent – We hold ourselves accountable and take pride in our work.

At ThrivePass, performance isn’t just about hitting goals—it’s about how you show up. We invest in our employees’ growth and encourage bold thinking, collaboration, and continuous learning. Join us in shaping the future of employee benefits!

What You’ll Do

We are looking for a skilled Sr Software Engineer with expertise in .NET Core & API integration to build, maintain, and enhance scalable web applications. You will collaborate with cross‑functional teams to develop high‑quality software solutions, ensuring performance, security, and maintainability.

• Analyze, understand, and map complex, heterogeneous third‑party APIs into normalized data models.
• Design and build connectors/integrations for SaaS platforms, field‑specific APIs, and proprietary vendor APIs.
• Develop and maintain data transformation and normalization pipelines that abstract away vendor‑specific differences.
• Handle authentication and authorization flows across diverse providers (OAuth2, API keys, SAML, custom flows).
• Build resilient integration patterns that gracefully handle API inconsistencies, rate limits, and error behaviors.
• Collaborate with product teams to design consistent, unified API schemas that scale across multiple providers.
• Establish strong testing, monitoring, and logging frameworks for integration reliability.
• Mentor and guide engineers in best practices for integration architecture and abstraction design.

What You Bring

We are seeking someone who is experienced in API‑first engineering and is comfortable working with complex data structures, integrations, and scalable system design.

Must Haves

• 4+ years of backend engineering experience, with significant time spent in API‑heavy environments.
• Proven ability to reverse‑engineer poorly documented APIs, understand complex JSON/XML payloads, and resolve mapping challenges.
• Deep experience with API normalization, data modeling, and abstraction design.
• Expertise with REST, GraphQL, and event‑driven integrations.
• Strong knowledge of integration middleware, API gateways, and webhooks.
• Familiarity with async processing, queuing systems, and retry strategies.
• Excellent problem‑solving skills in handling edge cases, non‑standard implementations, and schema drift.

Nice to Have

• Experience working at or integrating with unified API platforms.
• Familiarity with domain‑specific APIs (e.g., PRISM, HRIS, ATS, CRM, Healthcare APIs).
• Knowledge of schema evolution strategies, versioning, and API governance.
• Background in ETL/data pipelines or interoperability standards (e.g., OpenAPI, JSON Schema).

Why You’ll Love Working Here

We’re an inclusive and welcoming environment for all. ThrivePass is committed to fostering a workplace where everyone feels valued and respected. We do not and shall not discriminate based on race, color, religion (creed), gender, gender expression, age, national origin (ancestry), disability, marital status, sexual orientation, or military status in any of our activities or operations.

• A culture that values courageousness, authenticity, resourcefulness, and excellence (we don’t just say it—we live it).
• Opportunities to grow, learn, and level up your skills.
• A team that genuinely enjoys working together and celebrating wins.
• Competitive benefits package because we believe in walking the talk when it comes to employee well-being.

Salary Offered

Join Us!