Senior Backend Engineer (Python)

Location
Vilnius, Lithuania
Employment Type
Full-time
Part-time
Temporary
Fixed Term
Location Type
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Hybrid
Team
Engineering
Marketing
Design
Customer Support
Finance
HR
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Data
Overview
Application

Quick summary: We're looking for a backend engineer who can build Python systems that handle 50,000+ businesses running AI employees. You'll create the infrastructure that powers our agents - from handling LLM interactions to running background jobs to orchestrating workflows. All while managing large amount of business context. The challenge: writing clean, scalable code with great error handling so AI can understand failures and recover. You'll set patterns that make our backend stable and easy for the team to build on.

Why join Sintra?

We build AI employees for small businesses. Real helpers with personalities, not faceless chatbots. They handle the work that keeps owners up at night - answering customer emails, posting on social media, analyzing sales data. For business owners who've always worked alone, we're giving them their first team.

50,000+ businesses use Sintra because for the first time someone made AI actually useful for them. While Silicon Valley builds for tech companies, we're building for the florist who needs help with Instagram, the contractor drowning in invoices, the restaurant owner who can't keep up with reviews.

This is a unique moment in history. AI just became good enough to fundamentally change how small businesses operate. Behind every business is someone trying hard for their family. Someone with one goal - put food on the table. And our job is to help them succeed.

Having just raised our $17M seed round, we're off to the races. Small, fast-moving team building together in person. We ship daily, take ownership of what we build, and live by one principle - work is play.

Who we're looking for
  • 4+ years building Python backend systems at scale
  • Deep understanding of async programming, queues, and database design
  • Experience with LLM integration and handling AI-specific edge cases
  • Track record of improving entire codebases
  • Comfortable using AI tools to accelerate development

What you'll do
  • Build systems that let AI employees work autonomously - job queues, workflow orchestration, state management
  • Implement robust error handling for non-deterministic AI behavior - retries, fallbacks, user-friendly error states
  • Design database schemas and service architecture that scale
  • Own major features like background task systems and automated workflows
  • Create patterns and abstractions that make the backend consistent and maintainable
  • Optimize performance - reduce latency, identify and fix root causes of errors
  • Make our systems observable with proper tracking, logging and monitoring
  • Write documentation and establish patterns that level up the entire team

Our tech stack
  • Frontend: React
  • Backend: Python with FastAPI, Pydantic, PostgreSQL, Celery
  • Infrastructure: Railway, AWS, multiple LLM providers
  • DevOps & Tooling: Github Actions, Grafana

Our hiring process
  1. Fill in the application form. If we see a fit, we'll reach out for an intro call.
  2. Complete a take-home task that mirrors real work you'd do here. Be prepared to explain what you did and why.
  3. Join us for a trial day in Vilnius. Meet the team, see if we're right for each other.
  4. Get an offer if it's a mutual fit.

We understand good people have options, that's why we move super fast. Life's too short for drawn-out hiring processes.

What we offer
  • Compensation & Equity
    Top-of-market salary in Vilnius plus meaningful equity, so you own part of what you build.
    Salary range for this role: €5,000-8,000/month depending on expertise and experience.
  • Health & Wellness
    Health insurance, gym membership with personal trainer option, team lunch at the office.
  • Seamless Relocation
    Relocation bonus and support to make your move to Vilnius smooth.
About

We're looking for a hacker that can ship quality code fast and can work quite independently without too much oversight or guidance. You'll brainstorm the product with us and set off to ship great code that helps our customers grow their businesses.

Responsibilities
  • Build and ship features across the whole Sintra platform
  • Collaborate with design and product to turn ideas into reality
  • Own projects from architecture to deployment
  • Write clean, maintainable, and testable code
  • Improve performance, reliability, and scalability of the platform
  • Participate in code reviews and help shape engineering best practices
  • Contribute to technical decisions and roadmap planning
  • Move fast, stay curious, and take initiative.

What we expect from you
  • At least 4+ years of experience in Python development.
  • Ability to ship quality code fast.
  • Experience in startups or strong tech teams.
  • Work well independently and take ownership.
  • Product mindset - you care about user experience and impact.
  • Bonus: experience with scalable systems and clean architecture.

What you should expect from us
  • Salary ranges from €5,000 to €8,000 depending on expertise and experience
  • Work when and where you’re most productive — remote, hybrid, or in-office
  • Team lunch every day, cooked with love by our in-house chefs
  • Stock options after your trial period
  • Gym access + personal trainer (optional but encouraged — it’s fun with the team!)
  • Spontaneous team trips — we recently flew the team to San Francisco
  • MacBook and any other tools you need to do your best work
Apply Now
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