Company

Real estate deserves real evidence.

SirJohn is a small, bootstrapped team building the property-analysis tool we wished existed when we first tried to buy in Portugal. Here's who we are, how we work, and how to reach us — jump to any section from the menu.

Why we built it.

SirJohn started at a dinner table where three people trying to buy property in Portugal at the same time had the same problem: no way to check whether the price on the listing was fair.

Agents said yes. Google said maybe. The bank would say no, but only after six weeks of paperwork. By then the opportunity — or the warning — was gone.

The tool we wanted didn't exist. So we started building it. The first version valued a handful of Lisbon apartments against public comparables. The current version weighs 97 features against thousands of transactions, runs 25+ risk checks, and tells you — in plain language — what we'd want to know if we were the one buying.

2025 Q3

The dinner

Three buyers, three cities, same problem. The tool we needed didn't exist.
2025 Q4

First prototype

A handful of Lisbon apartments valued against public comparables.
2026 Q1

Model v2

97 features, 5,828 transactions, parish-level comparables, 25+ risk checks.
2026 Q2

Public beta

You're here. Any listing, any buyer, no account required.

How we work.

Four principles that make every small decision easier — and the big ones defensible.

Clarity over cleverness

A buyer shouldn't need a dictionary to understand a verdict. Every number we show has a plain-language explanation behind it, and a source they can check.

Evidence over opinion

When we say a property is overpriced, we'll show the comparables. When we say there's a risk, we'll name the source. "Trust us" is the opposite of what we're selling.

Honest about what we don't know

Confidence tiers, not fake precision. Limits stated up front. The tool tells you when it's unsure — so you know when to stop relying on it and pick up the phone.

AI in the loop, craft in the output

We're a small team by choice. Agentic workflows let us cover more ground than a team our size usually does — but the standards, the voice, and the judgement are ours.

Talk to us.

Questions, feedback, partnerships, or press — everything lands in the same inbox, and we read all of it.

What kind of message is it?

All channels reach the same team — telling us up front helps us route faster.

Buyers, agents, and owners

Question about an analysis, a feature request, or a bug? Pick ‘Product’ below — we triage daily.

Agents and partners

If you represent an agency, a buyer's advocate, or a platform that wants to integrate SirJohn analyses, pick "Partnership".

Press and research

Writing about the Portuguese housing market, foreign-buyer premiums, or real-estate transparency? We'll share data and pointers.

Send a message.

Concrete beats vague. A listing URL, a screenshot, or a specific question all help us reply faster.