Software Engineer II, Full Stack

About the company For over a decade, 700+ organisations have trusted Notnull's products to automate pieces of their operation. Among them the Portuguese armed forces, the tax authority, Social Security, and Teixeira Duarte.

Now we are building the autonomous company: AI agents that run a business's operations end to end, from customer support to closing the month.

About the opportunity The role is based in Porto, and is hybrid with 2 days a week in the office; competitive pay, equity, health insurance, and 25 days of PTO.

Models can already reconcile a month of payments against the bank statement, write the reminder for an invoice three weeks overdue or resolve a production issue affecting an angry customer. What nobody has solved is trust and reliability. An agent that touches real money has to run for hours without drifting, operate inside hard limits, ask before doing anything irreversible, keep a record its owner can read line by line, and ignore the email in its inbox telling it to send the refund somewhere else.

We are building that system; the first piece, coreloop.run, is in beta.

You would be the first engineer, working directly with the founder and a senior design lead. Decisions get made on the same day, and what you ship is in front of users immediately.

This is the closest you can get to building a software company from zero without founding one. One day you are building the highly available agent runtime; the next you are on calls with early users to figure out what should be next in the roadmap.

What you will do

• Build products from zero to one in a small team.
• Lead features end to end, from a one-paragraph brief to production.
• Set the engineering practices that keep quality high as the products grow.
• Keep the products that 700+ organisations already rely on running.
• Learn what it takes to build a product, and a company.

What we are looking for:

• Product-minded engineer
• 2+ years building and running complex software in production, across both frontend and backend
• Proficiency with TypeScript, Postgres, and React
• Comfortable working in a fast-moving, low-process environment
• Experience owning features end-to-end

Nice to have:

• Entrepreneurial mindset and strong ownership mentality
• BSc/MSc degree in Computer Science, or a similar technical degree
• Hands-on experience building with LLMs
• Background in distributed systems, databases, or container orchestration
• Good technical English communication skills

What we offer at Notnull:

• Interesting and challenging work
• Competitive salary and equity
• A lot of learning and growth opportunities
• Health and dental insurance
• 25 days of PTO

Location:

• Porto, Portugal
• Hybrid, 2 days a week in the office.

PS: In case you are curious, our products are built on Typescript (Tanstack Start and Hono), PostgreSQL, Redis, Temporal, and some Python but experience with these is not a requirement.