Staff Software Engineer — AI-Driven, Builder-First Platform

Taxfix; Madrid; On-site; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Mental health coaching

Yoga

Monthly flexible allowance

Stock options

30 vacation days

Work from abroad up to six weeks

Team social events

Tax declaration support

Dogs in office

Job summary

Taxfix is seeking a Staff Software Engineer to build core features for our flagship product, turning complex tax scenarios into simple, reliable experiences. You'll work hands-on in a cross-functional team and take ownership from discovery to production, with a strong emphasis on AI-first software development and maintainable code.

You’ll collaborate across frontend and backend stacks, design scalable services, and contribute to technical direction while raising the bar for quality, design, and

Qualifications

• Experience with React and Node.js for frontend and backend services.
• Experience with React Native is a plus.
• Ability to work across system boundaries with engineers outside your primary specialty.
• Experience using AI-assisted development tools to accelerate exploration and implementation.
• Ability to evaluate and troubleshoot AI-generated output with effective prompting.
• Experience with public cloud environments (Google Cloud, AWS, Azure).
• Familiarity with DevOps concepts including CI/CD, observability, and production operations.
• Understanding of authentication, databases, distributed systems, cloud infrastructure, and API integrations.
• Builder-first, pragmatic approach: turn customer problems into shipped outcomes, with initiative and fast iteration.

Responsibilities

• Partner with product, design, and engineering to understand problems and deliver outcomes.
• Own work end to end from discovery to release and iteration.
• Turn ambiguity into action with sound trade-offs for long-term maintainability.
• Contribute to technical direction and strategy aligned with product vision.
• Use AI-assisted development tools in daily work to accelerate exploration and delivery.
• Critically evaluate AI-generated outputs and apply safeguards.
• Share AI best practices and promote responsible experimentation.
• Improve developer experience with tools, automation, and engineering practices.
• Collaborate across product and platform teams to foster growth and feedback.

Skills

AI-assisted development

Cross-functional collaboration

Rapid iteration

Problem solving

Tools

React

Node.js

React Native

Job description

Taxfix is seeking a Staff Software Engineer to build core features for our flagship product, turning complex tax scenarios into simple, reliable experiences. You'll work hands-on in a cross-functional team and take ownership from discovery to production, with a strong emphasis on AI-first software development and maintainable code.

You’ll collaborate across frontend and backend stacks, design scalable services, and contribute to technical direction while raising the bar for quality, design, and