Portfolio OS · UK Landlords

Your portfolio isn't a spreadsheet problem.
It's a capital problem.

Keystone is built for portfolio landlords with 5–20 properties. Not a tracker. Not a spreadsheet upgrade. A financial intelligence layer — stress testing, DSCR, LTV, loan modelling — built around the decisions that actually move the needle.

Free to start. No card required.

Capital IntelligencePortfolio · Live view
1.42x
Portfolio DSCR
63.8%
Blended LTV
3
Expiring fixes (90d)
£214k
Available equity
Rate stress test — DSCR
5%
Pass
6%
Warn
7%
Fail
3 mortgage fixes expire in the next 90 days

You're making six-figure decisions
with five-minute tools.

  • Your mortgage spreadsheet doesn't know your refinancing window is closing.
  • Your letting agent's software thinks “yield” is a field to fill in, not a lever to pull.
  • Nothing tells you which property is dragging your DSCR below lender thresholds.
  • You find out your LTV has shifted when your broker tells you — not before.
  • Rate stress testing is a manual exercise you do once, in a panic, before remortgage.

Every tool built for landlords was built for the accidental ones. Two flats, one spreadsheet, a letting agent doing the rest.

If you've got 5, 10, 15 properties — mortgages across multiple lenders, LTV shifting as you refinance, capital decisions compounding in the background — you need something built to match how you actually think.

That's Keystone.


Three things no other tool gives you.

01
Capital Intelligence, not just tracking

Model debt service coverage across every property. Stress test your portfolio against the rate scenarios you choose. Know which assets are working — and which are quietly undermining your next deal.

DSCRRate stress testEquity modelling
02
Built around the mortgage, not the rent

Track every fix expiry. Model LTV shifts after remortgages. See which product transfer unlocks capital for your next acquisition — before you sit down with your broker.

LTV trackingFix expiry alertsLoan modelling
03
One view. Every property. Total clarity.

Stop stitching five tools into a picture that's already out of date. Properties, mortgages, cashflows, yield — one structured view. Spend less time assembling data and more time deciding what to do with it.

Portfolio dashboardCash flowYield analysis

“I built Keystone because I was a portfolio landlord using a spreadsheet I was embarrassed by. Every tool I tried was built for letting agents or accidental landlords with two flats. Nothing existed for someone who thinks in LTV, DSCR, and five-year capital plans. So I built it.”

Founder, Keystone  ·  keystonehq.app
★ Now in Beta

Built by a landlord.
For landlords.

No teams tier. No enterprise packaging. No feature bloat built for letting agents. Keystone is a capital intelligence tool for portfolio landlords who think in LTV, DSCR, and five-year plans — and want software that thinks the same way.

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