Senior Software Engineer (.NET, Node.js, React)

Headquarters: Poland URL: https://www.opsflowhq.com/

Role: Senior Software EngineerContract type: B2B, Independent contractorDuration: ~3-6 monthsDay rate: $250 - $325 USD (~$5k - $6.5k/month)Domain: Wholesale DistributionTech stack: .NET, Node.js, ReactLocation: Remote --- Our client, a UK-based B2B SaaS startup, is seeking a Senior Software Engineer on a contract basis to expand the functionality of their ERP product for the wholesale distribution industry. You'll work across the stack, spending 70% of your time on the backend and 30% on the frontend. As part of a small engineering team, you'll work alongside the technical founder and take ownership of the entire SDLC, from analysing business requirements to deployment. You won't just write code, you'll help shape the product and make important technical decisions. Company Our client is an early-stage B2B SaaS startup building a niche ERP software product for the wholesale distribution industry. The company is led by a technical founder with 15+ years of software engineering experience and is currently developing its product in close partnership with its first enterprise customer. Tech Stack Note that this role doesn't require proficiency across the entire stack. The product uses the following technologies:

Backend: ASP.NET Core, Node.js (Nest.js), PostgreSQL, RabbitMQ, Ably (streaming) Frontend: React, Next.js, TypeScript Mobile: React Native, Expo Infrastructure: Vercel, Digital Ocean

The backend is a dual stack with services split between .NET and Node.js. Responsibilities

Analyse business requirements and work with colleagues to break down features Design, build and run backend systems using .NET and Node.js Contribute to the development of the frontend systems using React.js Own full SDLC from requirements gathering to deployment and monitoring Collaborate on technical architecture, UX and product decisions. Take ownership of technical decisions, ensuring alignment with business goals Participate in planning and manage your own tasks.

Qualifications Essential:

5+ years of commercial experience in backend software engineering. Strong expertise with C#, ASP.NET and Node.js (Ideally with Nest.js or Express.js). Experience with Docker, Linux, Git, and container-based environments. Commercial experience in frontend development using React.js/Next.js/TypeScript. Experience in automated testing and understanding the value it unlocks. Comfortable owning projects end-to-end and working in the ambiguity of a startup environment. Strong engineering mindset and solution-oriented approach. Good product sense and empathy for users Can do attitude and ability to figure out things on your own.

Beneficial:

Experience in mobile development with React Native. Experience building CI/CD pipelines (e.g., Jenkins, GitLab CI, GitHub Actions). Experience working with cloud platforms (e.g., Vercel, DO, AWS, GCP). Experience working with fleets of IoT hardware. Responsible use of AI coding tools (Claude, Cursor).

Hiring process

CV review Intro call with talent partner (60 minutes) Interview with the client (60minutes) Offer stage

What we offer

Competitive compensation: $250-$325 USD per day (~$5k-$6.5k/month) Challenging project you d be proud to have in your portfolio High autonomy with an opportunity to influence technical decisions and product direction Direct collaboration with an experienced technical founder Work where you want, remotely

To apply: https://weworkremotely.com/remote-jobs/opsflow-senior-software-engineer-net-node-js-react