Senior Full Stack Developer

Justt is on a tear. We are reshaping a multi billion dollar problem with AI, our customer base is growing fast, and the momentum is real. Every quarter we are taking on bigger merchants, harder problems, and more interesting technical surface area. This is the moment to join a company that is past the "will it work" stage and squarely in the "how big can we go" stage.

You will work with sharp, ambitious people who care about what they ship. The product has clear customer impact, the roadmap is full, and your work will move metrics that matter to the business. If you are looking for a place where ownership is real, the pace is high, and your fingerprints will be all over the next chapter of the company, this is it.

What You Will Own

Build and own complex integrations with merchants, processors, and third party APIs end to end
Design and maintain the data pipelines that ingest and normalize customer data into Justt's schema
Improve reliability and observability across our integrations to reduce reactive load
Partner with Solutions Engineering on technical scoping for new customers
Mentor developers and help shape the technical direction of the Integrations team

How You Work

We value engineers who:

Take ownership end to end, from scoping through production support, without waiting for permission
Communicate trade offs clearly, especially when timelines, scope, and technical reality are in tension
Treat customer impact as a first class signal, not an afterthought
Build systems that other people can run, debug, and extend
Use AI tools as a force multiplier for drafting, synthesis, and triage, while still investing in deep system understanding

Requirements:

5 to 8 years of full stack engineering experience, with a strong backend bias
Deep experience with Node.js (TypeScript preferred) in production environments
Solid React experience for building internal tools and customer facing surfaces
Hands on experience with AWS (Lambda, ECS or EKS, S3, SQS or EventBridge, RDS or DynamoDB)
Practical experience building scrapers or browser automation with Playwright, Puppeteer, or Selenium
Strong fundamentals in API design (REST and webhook patterns), authentication, and error handling
Track record of building observable systems with structured logging, metrics, and tracing
Experience integrating with third party APIs at production quality, including rate limits, retries, idempotency, and reconciliation
Clear written and verbal English, including the ability to translate technical risk into business language for non engineering partners

Nice to have

Experience in payments, fintech, fraud, chargebacks, or any domain with high data sensitivity and regulatory pressure
Experience working closely with Solutions Engineering, customer success, or other customer facing functions
Experience with queue based and event driven architectures