Chimnie and Experian both work with UK property data, but they come at the market from fundamentally different positions. Experian is a global credit data bureau that offers property data as one component within a much broader financial data ecosystem. Chimnie is a specialist property data bureau built specifically around residential and commercial property intelligence, delivered via API to insurers, lenders, and proptech firms.
This comparison examines where each provider is strongest, what their products actually deliver for property-focused use cases, and which type of buyer each one fits best.
Who is Experian?
Experian is one of the three major credit reference agencies operating in the UK, alongside Equifax and TransUnion. Founded in 1996 and headquartered in Dublin, it reported global revenue of over $7 billion in its most recent fiscal year. The UK business serves financial services, telecoms, utilities, and insurance clients with credit data, identity verification, fraud prevention, and marketing analytics.
Within that range, Experian offers property-specific data products. These include sale detection signals that flag when a property goes on the market, equity estimates based on mortgage and valuation data, and property attribute data drawn from Land Registry, EPC records, and other public sources. The data is typically accessed through Experian's broader platform rather than as a standalone property API. Pricing is not published and is negotiated as part of enterprise contracts that often bundle credit, identity, and property data together.
Experian's strength in property data is closely tied to its credit bureau position. It can link property information to individual financial profiles - mortgage balances, credit histories, payment behaviours - creating a combined view that few standalone property data providers can match.
Experian UK credit and data services website screenshot
Who is Chimnie?
Chimnie was founded by Jon Francis, formerly of Google's innovation team, to make UK property data more transparent and accessible. The company runs two platforms: chimnie.com, a B2B property data bureau serving insurers, lenders, and developers; and chimnie.co.uk, a free consumer property research site with over 150,000 users whose activity provides ground-truth validation of the underlying data.
Chimnie's REST API covers 35 million UK residential properties and returns over 500 attributes per property, spanning EPC data, flood risk, subsidence indicators, conservation areas, listed buildings, rebuild cost estimates, and automated valuations. The company is completing a two-year ingestion of planning permission data from every UK local authority, which is launching imminently as the only full national planning dataset available from a single provider.
Pricing is published openly. Residential lookups start at £0.05 per property on PAYG, rising to £0.15 for the full premium dataset. Commercial property lookups are £0.45 each. Volume discounts are available through a published ratecard.
Feature comparison
Data scope and depth
Experian's property data is a subset of its wider consumer data platform. It covers property characteristics, sale events, equity, and some environmental factors, but the data is designed to enrich credit decisions rather than serve as a standalone property intelligence product. If you need to link property data to credit scores, affordability indicators, and identity verification in a single call, Experian can do that.
Chimnie's data is deeper on the property itself. Over 500 attributes per property include structural details, energy performance, multiple flood risk indicators, subsidence, tree-fall risk, solar panel detection, roof condition estimates, garden boundaries, and conservation status. If you need property-level detail for underwriting, risk modelling, or portfolio analysis, Chimnie returns more per lookup.
Automated valuations
Chimnie provides the UK's only free AVM, with UPRN-based lookups at zero cost. It runs separate listing price and sale price models and publishes micro-postcode level house price indices. Experian offers property valuation and equity data, but this is typically bundled into wider credit and financial products rather than available as a standalone AVM API endpoint.
Planning permission data
Chimnie has been completing a two-year national ingestion of planning permission records from every UK local authority, standardised into a single consistent schema. This dataset is launching imminently and captures extensions, loft conversions, outbuilding work, and change-of-use applications that affect property risk and value but don't yet show up in transaction or EPC records. Experian does not offer a comparable planning data product.
Rebuild cost estimates
Chimnie provides rebuild cost estimates with confidence intervals, finish-quality segmentation, and decomposed materials and labour breakdowns at regional level. This is a core product for insurance underwriting and claims validation. Experian doesn't offer rebuild cost data as a standalone product.
Credit and financial data
This is where Experian has no real competitor among property data providers. The ability to combine property data with credit bureau information - mortgage balances, payment histories, affordability metrics, identity verification - is unique to the credit reference agencies. Chimnie doesn't hold credit data and doesn't attempt to. If your use case requires linking property attributes to individual financial profiles, Experian is the obvious choice.
Pricing and access
Chimnie publishes its pricing on its website. You can sign up for a free trial, read the API documentation, and start making calls within minutes. There's no procurement process, no mandatory sales engagement, and no minimum commitment.
Experian's pricing is enterprise-negotiated. Property data is typically sold as part of a broader data contract that might include credit referencing, identity checks, fraud scoring, and marketing data. For large financial services firms already buying Experian credit data, adding property data can make commercial sense. For smaller firms or those who only need property intelligence, the procurement overhead is significant.
Where Experian is stronger
Experian's combination of property and credit data is genuinely difficult to replicate. If you're a lender who needs to assess both the property and the borrower in a single workflow, or an insurer who wants property risk data linked to policyholder financial profiles, Experian's integrated approach saves you from stitching together multiple providers.
The scale of Experian's operation also means enterprise-grade service level agreements, dedicated account management, and the compliance infrastructure that heavily regulated firms expect. For Tier 1 banks and large insurance groups, the Experian brand carries weight in procurement and audit processes that smaller specialist providers can't easily match.
Experian's marketing data and consumer segmentation tools - Mosaic, for example - add a layer of demographic and lifestyle context to property data that is useful for targeted product development and distribution.
Where Chimnie is stronger
Chimnie goes deeper on the property itself. Over 500 attributes versus Experian's more limited property dataset means more granular risk signals, more structural detail, and more environmental context per lookup. For anyone building property-level underwriting models, risk engines, or valuation tools, this attribute density matters.
The free AVM, planning permission data, and rebuild cost estimates are products that Experian simply doesn't offer in standalone form. The national planning dataset in particular fills a gap that no other single provider currently covers.
Price is a significant differentiator. Chimnie's published pricing starts at £0.05 per residential lookup. Even at the premium tier with all 500+ attributes, it's £0.15 per property. For high-volume use cases - enriching an insurance book, scoring a mortgage portfolio, or running batch valuations - the unit economics are materially different from enterprise-negotiated Experian contracts.
API access and developer experience also favour Chimnie. Full documentation is publicly available, there's a free trial, and integration can happen in days rather than the weeks or months typical of enterprise data procurement.
Chimnie website homepage screenshot
Who should choose which
Lenders and financial services firms that already use Experian for credit referencing and need property data integrated into the same workflow should stick with Experian. The combined credit-plus-property view is a genuine differentiator, and the marginal cost of adding property data to an existing Experian contract is often reasonable.
Insurers, MGAs, and reinsurers who need deep property-level risk data - flood, subsidence, rebuild costs, planning history, EPC, structural attributes - should look at Chimnie. The data is deeper, the pricing is more transparent, and the API is purpose-built for property risk use cases.
Proptech firms and data science teams building property analytics products need programmatic access to structured data at scale. Chimnie's API-first delivery, published documentation, and pay-per-lookup pricing make it the practical starting point.
For some organisations, using both makes sense. Experian for credit-linked property signals and consumer financial profiling; Chimnie for deep property intelligence, rebuild costs, and planning data. The two products are more complementary than competitive for most serious data buyers.
Conclusion
Experian and Chimnie occupy different positions in the UK property data market. Experian is a credit bureau that includes property data within a broader financial data ecosystem. Chimnie is a property data specialist that goes deeper on the property itself, at a fraction of the price, with a modern API built for developers.
The right choice depends on whether your primary need is linking property data to financial profiles, or extracting maximum property intelligence per lookup. For most property-specific use cases - insurance underwriting, risk modelling, portfolio enrichment, valuation - Chimnie delivers more data at lower cost with faster integration. For use cases where credit and identity data must sit alongside property attributes, Experian's integrated platform is hard to beat.
