Senior Python Engineer, Billing & Accounts

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 a system from scratch, and then watch a whole team rely on it? As a Senior Python Engineer, Billing & Accounts, you’ll create the Python foundation for Manychat’s Billing. It’s a domain where the complexity is in the details: payments, payment provider integrations, anti-fraud, and local regulatory compliance, all tied to a pricing model that every feature depends on. You’ll build systems that handle failure gracefully, because they’re handling real money. You’ll have real room to move. There’s no roadmap yet, so you’ll design systems end to end, make the architectural decisions, and experiment with what works best. Decisions move fast, and you’re trusted to make them. As new ventures and brands launch on top of Manychat, you’ll shape how Billing grows. Two mid-level engineers will join after you, and the foundation you lay is what they’ll build on. You’ll help them grow too. Sound like your next challenge? Let’s talk! 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 Python foundation: the environment where product features and the existing PHP backend work together. • Set the direction while there's no roadmap yet: experiment, make architectural decisions on your own, and design systems end to end. • Build async services for billing workflows: payments, payment provider integrations, invoicing, anti-fraud, and local regulatory compliance. • Design and integrate APIs, both internal and third-party, with clear and stable contracts. • Build for failure: retries, idempotency, consistency, and observability, so every payment is handled correctly. • Set the testing, CI/CD, and rollout practices this layer runs on, so the team can maintain, extend, and scale it after you. • Mentor and set the technical bar for the two mid-level engineers who join after you. • Work with cross-functional partners, so your technical decisions fit how the business actually runs. • Help Billing support the business as it scales and as new products and ventures launch on top of Manychat.. TO SHINE IN THIS ROLE 💥 You'll need: • 6+ years of commercial Python development in production, with Python as your primary language and recent hands-on work. • Strong expertise in modern Python frameworks (FastAPI preferred; Django or Flask are fine). • Solid experience designing and integrating APIs, including third-party services. • Strong understanding of async programming and concurrency (AsyncIO, non-blocking I/O). • Experience with PostgreSQL and large datasets. • Experience building and maintaining backend systems under production load, designed to last. • Strong testing practices (unit and integration tests; PyTest preferred) and experience with CI/CD pipelines and Docker. • Strong engineering judgment: you design systems end to end and make architectural decisions on your own. • Mentoring or leadership experience of any k