Founding Software Engineer
- Platform & Integrations
- Full-time
- Paris · hybrid
Own the systems that connect Qastel to a company's tools and apply its policies while AI is in use: integrations, backend infrastructure, the MCP gateway and runtime enforcement.
About the role
Qastel finds the AI a company uses by reading the systems it already runs, then applies the company's own rules while that AI is being used. Both depend on deep, reliable integrations: connectors for Microsoft Entra ID, Okta, Google Workspace, Netskope, Cloudflare and AI platforms, a browser extension, a desktop agent, and a gateway that sits in front of the tools AI agents call.
You will build these systems alongside Nordine, our CTO. This is a senior role for someone who takes a production system from design to operation on their own: you choose the approach, write the code, ship it and run it.
A decision service answers every AI request in real time: allow, block or ask for approval. It has to be fast, available and correct, because every employee of a customer feels a slow or wrong answer.
What you will do
- Build new connectors to identity, network security, device management and AI platforms, and make the existing ones reliable at scale
- Develop the MCP gateway that applies a customer's policies to the tools their AI agents call
- Keep the policy decision service fast and available under load
- Extend runtime enforcement across the browser, the desktop and developers' agents
- Improve the engine that merges signals from several sources into one AI inventory
- Own the backend and its infrastructure on a European cloud: data layer, background jobs, observability and releases
- Work with customers to test integrations against their real environments
Your first six months
You have shipped several integrations that customers asked for by name
Runtime enforcement has service-level targets, and we measure them
You own a part of the platform end to end, and Nordine no longer reviews every change to it
Who we are looking for
- A senior software engineer who has built and run production systems independently
- Strong in TypeScript and backend development, and comfortable with PostgreSQL
- You have built integrations against third-party APIs and lived with them in production
- You know enterprise identity and access: OAuth, OpenID Connect, SCIM
- You use coding agents in your daily work and review what they produce
- Working French or English, and willing to work in both
Nice to have
- Experience with the Model Context Protocol, API gateways or policy engines
- Experience with security products: secure web gateways, CASB, data loss prevention or endpoint agents
- Rust, for the desktop agent
- Experience with infrastructure as code
No one matches every line. If the job is one you want and you can do most of it, apply.
What you will work with
- TypeScript
- Bun
- Hono
- PostgreSQL
- Drizzle
- MCP
- Rust
- Terraform / OpenTofu
Hiring process
Introduction call
30 minutes with one of the founders, about your background, the role and what you are looking for.
Working session
A practical exercise based on real work for this role, which we go through together.
Meeting both founders
A longer conversation about how you work and what you would take on first, in Paris when possible.
Decision
We check references and give you an answer. Salary and terms are discussed openly with you during the process.
Interested in the Founding Software Engineer role?
Tell us about yourself. We read every application and reply to each one.