sumika — JP rental intelligence

sumika annotates listing pages on HOMES, SUUMO, and at home with the numbers you actually need to compare apartments — without making you click into every one. On every listing page (rule-based, no AI, no API key needed): • Parsed building, rent, layout, size, station, year built — all in one tidy panel. • Move-in cost — sums rent + management + deposit + key money exactly as parsed off the page, with a 2-year total estimate and an honest "+ misc fees" note for the items the page doesn't list (insurance, lock change, agent fee, guarantor). • ¥/㎡ so you can compare value across listings at a glance. • Rent vs. local median — once you've browsed a handful of same-spec listings, every new one shows "8% above the local median" or "−22% — possibly bait." • Same-building grouping — when you've seen multiple units in one building, they're surfaced together. • Per-room sizes in m² (converted from 帖 at the legal 1.62 m²/帖 standard). On search-results pages — small chips on each card with ¥/㎡ and a bait warning, so you can triage 30 listings in 10 seconds. Saved listings + comparison — star any listing with ★, then open the toolbar popup for a sortable side-by-side table with notes, "saved N days ago" timestamps, and a CSV export. Optional AI features — strictly opt-in. A master switch (off by default) gates four buttons: analyze the floor plan, score the listing against your free-text preference, draft an inquiry letter in Japanese, or pick the best from your saved listings. Each is a button click — nothing fires automatically. You supply your own Anthropic API key; it stays in your browser and is sent only to api.anthropic.com. Privacy — no analytics, no telemetry, no remote code. Everything stays local by default. Bilingual UI (日本語 / English) with a toggle in the Options page.