5Blue Software

Senior Full Stack AI-first Saas Engineer

Bulgaria, Croatia, Czechia full-time Senior Salary not listed
full-time Senior level Technology & IT Curated
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About the role

Hi there!
We are currently looking for a strong Full-Stack Developer-AI-First SaaS Engineer

About Us:
5Blue Software is an Israeli-Ukrainian software development company specializing in custom software development, staff augmentation, dedicated engineering teams, AI solutions, and CTO-as-a-Service. We help startups and mid-sized companies scale faster with vetted engineering talent across Europe.
About the project:
Join a fast-growing AI-first product company building a B2B SaaS platform that helps organizations simplify security, compliance, and AI governance.
The platform automates processes that traditionally require significant manual work — from evidence collection and monitoring to audit preparation and certification workflows.
You'll join a lean, highly collaborative international engineering team distributed across Europe, Israel, and South Africa.
About the role:
We're looking for a Senior Full-Stack Developer who is comfortable working across both frontend and backend and enjoys taking ownership of features from idea to production.
This is an AI-first engineering environment. AI is used both as part of the product and as a standard part of the development workflow. You'll use AI-assisted development tools to accelerate implementation, debugging, testing, and refactoring while maintaining strong engineering judgment and the ability to write and understand code independently.
You'll work closely with Engineering and Product on system design, architecture, and feature development, with a particular focus on building high-quality React experiences while contributing confidently to the backend.
What you'll do:

Build and deliver full-stack features end to end using React, TypeScript, and Node.js.

Develop intuitive, performant, and scalable frontend experiences for a complex B2B SaaS product.

Implement backend services, APIs, business logic, and third-party integrations.

Develop and integrate AI-powered product features.

Participate in system design and architectural decisions.

Use AI-assisted development tools such as Claude Code or similar as part of your everyday workflow.

Review, debug, test, and improve AI-generated code while maintaining ownership of the implementation.

Take responsibility for the CI/CD and DevOps aspects of the features you build.

Work closely with Engineering and Product to define requirements and technical solutions.

Participate in Agile ceremonies and collaborate with a distributed international team.

Communicate technical decisions clearly and confidently in English.

What we're looking for:

5+ years of professional software development experience, with roughly 5+ years of experience with Node.js as a guide rather than a hard line. Real depth in a closely related stack can also count.

2+ years of professional experience with React as a guide.

Strong experience with TypeScript.

Hands-on experience with Express, Fastify, or a similar API framework.

Strong full-stack capabilities and the ability to work comfortably across frontend and backend, even with a natural lean toward one side.

Production experience with microservices architecture.

Working familiarity with AWS or a comparable cloud provider such as GCP or Azure.

Hands-on experience with both relational and non-relational databases, such as PostgreSQL and MongoDB or similar.

Experience integrating third-party REST APIs into a production system, beyond just building your own API endpoints.

Real experience shipping AI-powered features in a live product, not just experimenting with AI on personal projects.

Experience using AI tools such as Claude Code or similar as a genuine part of your development workflow, balanced with the ability to write and debug code yourself, unaided, live.

Working proficiency in DevOps, QA, and CI/CD at the level expected of a senior engineer, not a dedicated DevOps hire.

Strong spoken English, comfortable holding a real-time technical conversation such as a system design discussion.

A background from a product or SaaS company rather than a project-based agency. Experience in security, compliance, GRC, or developer-tools SaaS is a natural fit, though not required.

Nice to have:

Experience with LangChain, LangGraph, or a comparable agent/AI framework.

Python experience alongside your primary stack.

Experience with Docker, Kubernetes, or containerization more broadly.

A CS / Software Engineering academic background.

A track record as the front-end "champion" on a full-stack team: someone who can carry that surface area while still holding their own on the backend.

What we offer:
— Flexible Work Environment: Opportunity to work remotely.
— 1:1 English Classes: Individual English language training.
— Premium Medical Insurance: Comprehensive health insurance.
— Great Team: Supportive, collaborative, and dynamic international team.
— Equipment Provided: All necessary equipment supplied.
— Accounting Support: Full accounting assistance in Ukraine and Poland.
— Paid Time Off: 18 days of annual vacation and 7 days of sick leave without a doctor's note.
— Flexible Payment System: Convenient payment solution with multiple withdrawal options.
If you're a strong full-stack engineer who enjoys building real products, taking ownership, and using AI to become a more effective developer — we'd love to hear from you.
Originally posted on Himalayas

Interview prep

Walk in with sharper answers.

Use these suggested prompts to prepare. They are not questions supplied by the employer.

Senior
Technology & IT Accounting API integration Javascript MySQL Project Management Senior level

Practice questions

  1. Tell us about work you have done that is close to the Senior Full Stack AI-first Saas Engineer role.
  2. How would you approach your first 30 days at 5Blue Software?
  3. Which of Accounting, API integration and Javascript have you used recently, and what did it help you achieve?
  4. How have you led people, improved a process, or made a hard decision in a previous role?
  5. How do you handle busy days, changing priorities, or pressure at work?

Prepare before the call

  • A recent example that proves your experience with Accounting, API integration and Javascript.
  • One short story with a problem, your action, and the result.
  • Two examples that show the strengths listed on your CV.
  • A clear reason why this role and company interest you.
  • Your availability, preferred work style, and salary expectations.

Ask them

  • What would success look like in the first 90 days?
  • What are the main problems this hire should help solve?
  • How does the team give feedback and measure good work?
  • What does a normal working week look like for this role?
Practice line

I am interested in the Senior Full Stack AI-first Saas Engineer role at 5Blue Software. My relevant experience is [your example], where I [your action] and achieved [your result].

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