Product Engineer | Callimacus.ai

Way of work: On site Milano, zona Moscova
Key tech skills: TypeScript (Node.js), React, AWS, RAG/LLM/agent orchestration
Experience: Middle/Senior
Total comp: 45-85k (45-60k middle, 70-85k senior) plus equity and benefits

About Callimacus

Callimacus is reinventing how people interact with the web. Since the Nineties, digital experiences have been built around a fixed paradigm: predefined pages, menus, and navigation trees, that no longer fits how people browse, shop, and get informed today.

Callimacus built the engine for something different: a multi-agentic platform that plugs into a company's existing stack, reads real-time signals to understand what a visitor wants, and composes the entire interface around that intent in milliseconds, selecting the most relevant content and components as the person interacts.

Founded in 2024 with early backing from Brunello Cucinelli, now both an investor and a customer, Callimacus launched in January 2026 to strong enterprise interest, and recently raised an important investment from Salesforce Ventures, its largest AI investment in Italy. The team is small, product-focused, and founder-led, working on hard problems nobody has solved before.

What you'll build

You'll join a small senior team at the point where the platform's foundations are still being set. Callimacus is in production with demanding customers, and the architecture, the performance envelope, and the shape of the developer experience are all still yours to influence. Decisions you make in your first months will still be load-bearing in three years.

• Own the orchestration layer. Design how our agents turn multi-dimensional visitor signals into intent, and intent into a fully composed interface — in milliseconds, in production, for demanding enterprise customers.

• Put inference on the critical path — and keep it fast. Model routing, caching, fallbacks, and latency budgets for a system where “the model is thinking” is not an acceptable state.

• Build the retrieval and selection pipeline. Embeddings, vector search, ranking, and the content-selection logic that decides what a visitor sees next.

• Make agent behavior measurable. Evals, tracing, and feedback loops, so quality is an engineering discipline rather than a feeling.

• Shape how customers extend the system. Tools, guardrails, and configuration — the primitives others will build on.

One note before applying

Callimacus believes working side by side leads to faster progress, stronger ramp-up, and a culture built around community.
For the next months, the team has chosen to be in-person first, they've invested in making the office worth coming to, and are happy to support your commute.

They also don't work by tickets: priorities get redefined often, sometimes mid-week, and you'll need to be comfortable with that. If you're set on remote work or a settled roadmap, this isn't your role. If you want to be in the room while the platform takes shape, they'd like to meet you.

What you'll build

You'll join a small senior team at the point where the platform's foundations are still being set. Callimacus is in production with demanding customers, and the architecture, the performance envelope, and the shape of the developer experience are all still yours to influence. Decisions you make in your first months will still be load-bearing in three years.

• Own the orchestration layer. Design how the agents turn multi-dimensional visitor signals into intent, and intent into a fully composed interface in milliseconds, in production, for demanding enterprise customers.

• Put inference on the critical path, and keep it fast. Model routing, caching, fallbacks, and latency budgets for a system where "the model is thinking" is not an acceptable state.

• Build the retrieval and selection pipeline. Embeddings, vector search, ranking, and the content-selection logic that decides what a visitor sees next.

• Make agent behavior measurable. Evals, tracing, and feedback loops, so quality is an engineering discipline rather than a feeling.

• Shape how customers extend the system. Tools, guardrails, and configuration, the primitives others will build on.

What matters at Callimacus

These are the same for every role.
Callimacus hires people who get the job done and care about the end result: the product, the experience, the people using it.

• Ownership: you feel deeply responsible for your work and behave accordingly, from design through production and after. You don't wait to be told what to do; you see problems and act. "It's not my job" is not part of your mindset.

• Invention: you light up at hard problems and are creative at finding solutions. You experiment, get your hands dirty, and land things. You hold very high standards and always look for ways to improve.

• Team-oriented: you're someone others can count on. You support the best idea even when it's not yours, disagree productively, give and take feedback, share credit, and take on unglamorous work when that's what the team needs.

The craft bar for this role:
- Strong TypeScript and Node.js, with a track record of shipping production systems
- AI systems literacy: RAG, embeddings, vector databases, and agent orchestration are part of your working vocabulary
- You don't need to have trained a model; you do need to know what breaks when inference sits on the critical path.

Where you might be strong:
Callimacus is early-stage, and nobody is strong in all of these, they don't expect you to be. Depth in two or three, plus curiosity about the rest, is what wins. If that's you, apply even if you don't tick every box.

• Agent orchestration and multi-step LLM workflows

• RAG, embeddings, and vector databases in production

• Prompt and eval engineering at scale

• Streaming and real-time systems

• Backend performance work — latency budgets, caching, load

• Data pipelines feeding AI systems

Bonus points

• Experience as an early engineer at a startup or fast-growing company

• Shipped inference-heavy or data-intensive products

• Open-source work in the AI tooling space

What Callimacus offers

Callimacus wants to be a place where talented, driven people flourish, and takes that commitment seriously. A few things you'll find (and there will be more in the upcoming months):

• A product that will light you up. You'll work at the frontier of what AI can do today, on problems nobody has solved before, which means most weeks you'll be reasoning from first principles rather than looking up how it's done. What you land becomes the way it works.

• An exceptional opportunity for growth. You'll work directly with the founders in a small, senior, talent-dense team, with high agency from day one, and play an essential role in the growth of the company.

• Equity. You'll own a real piece of what you're building, aligning your growth with the company's long-term success.

• Amazing offices in the centre of Milan. In the Moscova neighbourhood, one of the liveliest areas in the city and twenty minutes from anywhere.

• Top-of-the-market health insurance. Comprehensive cover, for you and the people who depend on you.

• A welfare budget you decide how to spend. Gym, mental health, museums, courses, travel: whatever actually makes your life better.

• Genuinely good food all day. High-quality, restaurant-level meals, including breakfast, lunch, and all-day snacks.

• CCNL Metalmeccanico

L'annuncio è rivolto a candidati di entrambi i sessi, nel rispetto del D.lgs. 198/2006 e s.m.i., e a persone di ogni età, nazionalità, orientamento sessuale, identità di genere e appartenenza etnica, nel rispetto dei principi di non discriminazione e pari opportunità.