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Sr. Software Engineer, Fullstack - Remote

Firstup

Remote · United StatesFull Time$120k–$190k
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Sr. Software Engineer, Fullstack - Remote at Firstup is a full time role based in Remote · United States (remote). The listing states pay of $120k–$190k. It was published on 17 August 2026 and was open at last check.

Sr. Software Engineer, Fullstack - Remote at Firstup — key details
RoleSr. Software Engineer, Fullstack - Remote
CompanyFirstup
LocationRemote · United States (remote)
Employment typeFull Time
Pay (as listed)$120k–$190k
Published17 August 2026
StatusOpen at last check

Who We Are

At Firstup, our mission is to improve the employee experience at every moment that matters, large and small. As the communication pipeline for the world's workforce, we now serve 40 of the Fortune 100 companies, reaching and connecting more than 17 million employees daily.

Our employees are experts in the employee experience, workforce communications and technology.

Joining Firstup means joining a movement to make work better for every worker. As the world’s first intelligent communication platform, Firstup meaningfully engages employees at every moment from hire to retire, and delivers engagement insights to help companies support, promote and retain their talent. Our movement has taken root and is evident in our world-class customer base. Now we need your help. Ready to make a difference in the world?

Job Summary

We're looking for a Senior Full Stack Engineer who thrives at the intersection of craft and scale. You'll design and deliver large-scale, multi-tenant cloud services — with a relentless focus on availability, fault-tolerance, and elegant architecture. You'll set the bar for engineering quality and help elevate those around you.

Responsibilities

Core Engineering & Ownership: Build and own scalable SaaS applications end-to-end — frontend, backend, and data layers. Write production-grade code that is reliable, readable, efficient, and testable. Raise the bar through thoughtful code reviews and comprehensive documentation.

System Architecture: Design future-ready architectures and proactively close gaps before they become problems.

Performance & Reliability: Drive system availability and performance — investigate, analyze, and resolve reliability issues across the stack. Recognize opportunities and advocate for better performance and efficiency of software, systems, and processes across teams.

Shift Left Testing & Quality:You champion a rigorous 'shift-left' quality culture, embedding comprehensive testing—unit, integration, and contract—early and continuously in the development lifecycle, not as an afterthought.

AI Integration: Leverage and advocate for AI-assisted tools (e.g., GitHub Copilot, Claude) to accelerate development while maintaining rigorous engineering judgment and accountability for code correctness.

Leadership: Drive team-wide best practices, conduct quality code reviews, and mentor engineers to elevate overall engineering quality.

Collaboration (Product & Design): Partner with Product and Design to translate requirements into intuitive UI, making informed technical trade-offs in the face of ambiguity.

Collaboration (Engineering Standards): Champion engineering best practices across teams and collaborate on solving complex, high-impact problems.

Minimum Qualifications

  • Bachelor's degree in Computer Science or related field, or equivalent experience.
  • 5+ years building reliable, performant applications and microservices in production environments. Proven full stack fluency - you're comfortable across frontend, backend, and the database layer.
  • A polyglot mindset — you evolve with the tech. Familiarity with Ruby on Rails, TypeScript, Node.js, or React.js is a strong plus.
  • Proven full-stack experience across frontend (React.js), backend, and database layers.
  • Technical depth in at least one engineering domain: distributed systems, multi-tenant SaaS, application databases, networking, security, serverless, event streaming, or similar.
  • A genuine drive to build beautiful, intuitive products with the customer always in focus. Innate curiosity — you love learning and have a desire to teach and lift others. Strong communication skills and openness to collaborative idea-sharing across teams.

Preferred Qualifications:

  • Core Stack Experience: Familiarity with Ruby (including Ruby on Rails), TypeScript, Node.js, or React.js is a strong plus.

Why Firstup?

Because you care - about people, the work you do, and the connections you make. Work is such a large part of life; it only makes sense to make it awesome.

If you want to engage brilliant minds in a high-growth and inclusive environment where ideas are rewarded regardless of who they come from, join us. This is a rapidly changing space so if you thrive on ambiguity, are hungry for a challenge, and have the guts to speak your mind, you could be a perfect fit.

We offer an excellent PTO program, great health benefits, a casual and friendly environment, remote work, and a leadership team who truly believes in your growth – both personally and professionally.

Firstup is committed to providing equal employment opportunities to all applicants for employment and to all employees, without regard to race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, protected disability, veteran status, or any other protected status in accordance with applicable federal, state or local laws.

Originally posted on Himalayas

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Create your free OnJob profile to apply — we'll take you to Firstup's application after sign-up. · Posted 17 Aug 2026.

Sr. Software Engineer, Fullstack - Remote at Firstup — questions answered

What does the Sr. Software Engineer, Fullstack - Remote role at Firstup pay?

The Sr. Software Engineer, Fullstack - Remote at Firstup listing states pay of $120k–$190k for the Remote · United States (remote) position. That figure is taken directly from the employer's own posting as published, not estimated or averaged from other roles.

Is the Sr. Software Engineer, Fullstack - Remote role at Firstup remote?

Yes — Firstup advertises this Sr. Software Engineer, Fullstack - Remote role as remote, tied to Remote · United States, and it is listed as full time work. Remote terms come from the employer's own posting, so confirm the expected working hours, timezone and any on-site days with Firstup before you apply.

Is the Sr. Software Engineer, Fullstack - Remote role at Firstup still open?

The Sr. Software Engineer, Fullstack - Remote posting at Firstup was open at OnJob's last check of the employer's careers page, having been published on 17 August 2026. OnJob re-checks source listings on each build and marks a role closed once it disappears, but listings can close without notice, so the employer's own page is the final word.

How do you apply for the Sr. Software Engineer, Fullstack - Remote role at Firstup?

Apply to the Sr. Software Engineer, Fullstack - Remote at Firstup role through OnJob with a free profile: OnJob scores your fit against the listing, shows the skills lowering that score, and submits an ATS-ready profile to Firstup's own application page. Creating a profile is free and needs no card.

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