Senior Software Engineer - Web App & DevEx

Runware; Belgium; Remote; EUR 80,000 - 110,000; Full time

Benefits offered by this job

Generous PTO

Stock options

Remote-first setup

Flexible hours

Family leave

Company retreats

Job summary

Runware is seeking a Senior Software Engineer to build and evolve systems and APIs powering our Web App and Developer Experience. You will collaborate with backend and frontend teams, product, and design to deliver reliable APIs and production-ready features.

You’ll own backend work from requirements to delivery, shaping technical decisions and contributing to robust, scalable systems while maintaining a strong focus on quality, security and performance.

Qualifications

• Backend API design and implementation
• Experience building reliable production systems
• Strong understanding of API design and distributed systems
• Security, performance and reliability focus

Responsibilities

• Build and maintain internal and developer-facing APIs and services powering Runware's Web App and DevEx
• Develop and evolve public API functionality including task types, validation, routing, and WebSocket/REST behavior
• Own and maintain the Admin API and panel as an internal platform used across Runware
• Work with usage, billing and customer data to ensure accuracy and reliability, including Stripe
• Investigate and resolve production issues and security vulnerabilities affecting the Web App and APIs
• Write, test and review clean, maintainable code with strong engineering practices
• Clarify requirements with Product/Design and define well-scoped technical solutions
• Contribute to technical decisions across frontend and backend boundaries with the wider Backend team

Job description

We're looking for a Senior Software Engineer to help build and evolve the systems and APIs that power Runware's Web App and Developer Experience (DevEx).

You’ll work closely with backend engineers, frontend engineers, Product, Design and other teams to build reliable internal and developer-facing APIs and functionality that make complex AI infrastructure simple to use.

You’ll take ownership of backend work from understanding requirements and technical constraints through to implementation and delivery, contributing to the quality, reliability and evolution of the Web App and its supporting APIs.

This role combines technical depth with product thinking and collaboration. You’ll be expected to work autonomously, contribute to technical decisions and help turn ambitious ideas into robust production systems.

What you'll do

• Build and maintain internal and developer-facing APIs and services that power the Web App and developer experience
• Develop and evolve public API functionality, including task types, validation, routing and WebSocket/REST behaviour
• Own and maintain the Admin API and panel as an internal platform used across Runware
• Work with usage, billing and customer data to ensure accuracy and reliability, including Stripe
• Investigate and resolve production issues and security vulnerabilities affecting the Web App and its APIs
• Write, test and review clean, maintainable code, contributing to strong engineering practices and code quality
• Work with Product, Design and engineering teams to clarify requirements, identify dependencies and define well-scoped technical solutions
• Contribute to technical decisions, work across frontend and backend boundaries where appropriate, and collaborate with the wider Backend team where specialist knowledge or shared systems are involved

Requirements

• Strong experience building backend systems and APIs
• Strong programming experience in one or more backend languages, with the ability to quickly learn and work effectively in new languages and technologies
• Experience building reliable, maintainable and well-tested production systems
• Good understanding of API design, asynchronous workloads and distributed systems concepts
• Strong engineering fundamentals around security, reliability and performance
• Strong communication and collaboration skills, with the ability to work effectively across engineering, Product and Design
• Strong ownership and autonomy, with good judgement around when to involve others
• Comfortable using AI-assisted development tools and agents to improve productivity, while understanding their limitations and maintaining responsibility for the quality, security and correctness of the resulting code

Nice to have

• Experience with PHP, Symfony and/or Doctrine
• Experience with WebSockets
• Experience building public APIs or other developer-facing products
• Experience with usage-based billing, credits or financial data
• Experience contributing to architectural decisions and mentoring other engineers

Benefits

We're a remote-first collective, meeting in person twice a year to plan, brainstorm, celebrate wins, and enjoy some face-to-face time. We have core hours for cooperative working and calls, but outside of that your calendar is yours. Work the hours that let you perform at your peak while also building a healthy life.

We move quickly and hold a high bar, but we also believe sustainable performance matters. After major releases and milestones, we create space for the team to properly unplug, recharge and come back with the energy to tackle what's next.

• Generous paid time off - vacation, sick days, public holidays
• Meaningful stock options - share in the upside you create
• Remote-first setup - work from home anywhere we can employ you
• Flexible hours - own your schedule outside core collaboration blocks
• Family leave - paid maternity, paternity, and caregiver time
• Company retreats - twice-yearly gatherings in inspiring locations