Senior Python Engineer, Billing & Accounts

Barcelona 🇪🇸 or Amsterdam 🇳🇱. Relocation support is available if you need it.

WHO WE ARE 🌍

Creating content that resonates is great — turning that attention into growth is even better. That's what Manychat does.

Our AI-powered automations help creators and brands engage with audiences across Instagram, Messenger, WhatsApp, and TikTok — at the right moment, with the right message, minus the manual work.

We're 400+ people across three continents behind the leading platform for conversational growth, with AI skills shaping how we build, how we work, and how we grow.

WHO WE'RE LOOKING FOR 🌟

Want to build something from zero, with full ownership and C-level backing? Ready to set the engineering bar as the first person on the team? Excited to design and build business-critical systems with zero tolerance for failure?

Then keep reading, because this role hands you a piece of Manychat that doesn't exist yet: Billing's own Python layer.

Billing runs entirely on PHP today, and it works. But Manychat is entering a multiproduct chapter: new ventures and brands are launching on top of the core platform, and Billing has to carry that weight. This isn't a rewrite. It's a foundation that doesn't exist yet — a Python layer built to carry payments, billing, anti-fraud, and compliance logic at scale.

There's no roadmap for this yet. You'll be the first engineer on it, which means you set the patterns, the standards, and the judgment calls, and shortly after, you'll mentor two engineers who join to build alongside you.

YOUR FUTURE TEAMMATES 👋

We run Manychat under serious load, every day, and get it ready to handle even more. The stack is built for speed and durability, and we're already working at the front of the AI era, not scrambling to catch up. We're the ones who shape and own what gets built. You'll do that work alongside a team that already moves fast, holds a high bar, and has each other's backs when it counts.

WHAT YOU'LL DO 🚀

• Design and build Billing's first Python layer: the bridge between product features and the existing PHP core.

• Define the patterns for service communication, orchestration, and how responsibility splits between Python and PHP.

• Build scalable, async services for high-load, latency-sensitive billing workflows: payments, invoicing, anti-fraud, and regulatory compliance.

• Own API contracts across systems, keeping them stable, backward-compatible, and clearly bounded.

• Identify functionality worth extracting from the PHP core into Python services where it improves performance or maintainability.

• Design for failure: retries, idempotency, consistency guarantees, and the observability to catch problems early.

• Set the testing strategy, CI/CD, and rollout practices this layer will run on, since you're the one building them from scratch.

• Mentor and set the technical bar for two mid-level engineers who join the team after you.

• Partner closely with Platform and Product to keep architecture grounded in real business needs, not just technical elegance.

• Help shape how Billing supports new products and ventures being built on top of it.

WHAT SUCCESS LOOKS LIKE 🎯

First 3 months: you understand the PHP core, Billing's constraints, and Product's existing Python layer well enough to make confident calls, and the first pieces of Billing's own layer are in production.

By end of year: the foundation is handling real billing traffic, and you've helped bring the first two engineers onto the team.

Beyond: Billing's Python layer is the reference pattern other teams build on, and your judgment is why it holds up.

TO SHINE IN THIS ROLE 💥

You'll need:

• 8+ years of commercial Python development in production environments, including recent hands-on work.

• Strong expertise in modern Python frameworks (FastAPI preferred; Django/Flask fine).

• Real experience designing and integrating APIs, including third-party services — this is integration and product development work, not infrastructure work.

• Solid understanding of async programming and concurrency (AsyncIO, non-blocking I/O).

• Experience working with PostgreSQL and large datasets.

• Experience building and maintaining high-load backend systems.

• Strong testing practices (unit and integration tests; PyTest preferred).

• Experience with CI/CD pipelines and Docker.

• Strong ownership and product mindset: you connect engineering decisions to business impact and can defend your calls under scrutiny.

• Experience building an environment or foundation comparable to what you'd be building here, ideally under real system constraints rather than a clean slate.

It would be great if you have:

• Experience working with money: billing, invoicing, or payment systems.

• PHP experience.

• Scale-up company experience.

• Experience with loaded projects and queue systems.

• Infrastructure skills.

• Deep third-party API experience.

• Knowledge of different NoSQL solutions and analytical systems.

• Replication, partitioning, sharding, PL/pgSQL, and other marks of serious database work.

WHAT WE OFFER 🤗

We care deeply about your growth, well-being, and comfort:

• 🌍 Hybrid onboarding to start remotely and relocation support for you and your family.

• 💙 Comprehensive health insurance for you and your family.

• 📚 Professional development budget for conferences, courses, and learning resources.

• 🫶 Flexible benefits package tailored to your priorities.

• 🪴 Hybrid work and generous leave options for work-life balance.

• 🍽 In-office perks including free meals and snacks.

• 🤝 Company-funded sports activities, annual offsites, and team-building events.

Manychat is an Equal Opportunity Employer. We’re committed to building a diverse and inclusive team. We do not discriminate against qualified employees or applicants because of race, color, religion, gender identity, sex, sexual preference, sexual identity, pregnancy, national origin, ancestry, citizenship, age, marital status, physical disability, mental disability, medical condition, military status, or any other characteristic protected by local law or ordinance.

This commitment is also reflected through our candidate experience. If you have individual needs that may require an accommodation during the interview process, please indicate this in your application. We will do our best to provide assistance throughout your interview process to ensure you’re set up for success.