Methodology

How the data on this site is sourced, transformed, refreshed and validated.

Primary sources

Source	What we get	Refresh
HM Land Registry Price Paid Data (pp-complete.csv) ↑	Full register, ~30M residential transactions since 1995	Monthly
HM Land Registry Price Paid monthly update ↑	Monthly delta (added/changed/deleted records)	Daily check
HMLR reuse terms ↑	OGL-aligned licence governing reuse	n/a

Refresh process

HMLR publishes the complete Price Paid CSV monthly. We pull pp-complete.csv directly from HMLR's S3 mirror within 24 hours of release.
The CSV has 16 columns, no header. Each row is parsed: dates from YYYY-MM-DD HH:MM to ISO, transaction UUIDs unwrapped from braces, district names slugified for clean URLs.
Rows stream into a new table transactions_new via Postgres COPY. No row-by-row inserts.
Indexes are built on the new table after the load completes (GIN tsvector for address full-text, GIN trigram for fuzzy, btree for postcode / outcode / district / date).
A single atomic ALTER TABLE ... RENAME swaps the new table in. The old table is preserved for 24 hours as a rollback safety.
Local-authority aggregates (counts, medians) are recomputed.
Total runtime: roughly 20-30 minutes on the production Hetzner box. The user-facing site stays available throughout.

What the data contains

Per transaction we hold:

HMLR transaction UUID
Price paid (in pounds), transfer date
Postcode, address fields (PAON, SAON, street, locality, town, district, county)
Property type (detached / semi / terraced / flat / other)
New-build flag, freehold / leasehold
HMLR's "PPD category": A for standard transactions, B for additional types (right-to-buy, repossession, deeds of gift, etc.) which can distort comparisons

No owner names. No PII at record level.

Known limitations

Coverage is England and Wales only. Scotland (Registers of Scotland) and Northern Ireland (Land Registry of Northern Ireland) publish separately and are not in this dataset.
HMLR lags new builds and shared-ownership sales by up to ~6 months from completion. Very recent sales may not be visible yet.
PPD category B (additional transactions) is included for completeness but should be excluded when computing typical-market medians. The data we surface flags this.
HMLR's address fields (PAON, SAON, street) follow strict capitalisation conventions but do not normalise "Flat 1" vs "1A" consistently. Some properties have multiple address representations across their sale history.
We do not yet cross-reference with the EPC register; that's on the build roadmap.

Corrections

Spot an error in how we display a sale? Email [email protected] and I'll fix or remove the issue within 48 hours.

For corrections to the underlying HMLR record (an address typo, a wrong price), contact HMLR directly. Our copy refreshes monthly and your correction propagates automatically.