Frequently Asked Questions

You can get a free API key instantly — no credit card required:

1. Go to /register
2. Enter your email address
3. Copy your key from the success page (shown only once)

For higher rate limits, see our paid plans.

Pass your API key in the X-API-Key header on every request:

curl https://api.homeportfolio.com/v1/property/100030048320 \
  -H "X-API-Key: hp_live_your_key_here"

You can also pass it as a query parameter ?api_key=hp_live_..., but the header is preferred for security.

Try the interactive API Explorer in your browser, or run this curl command:

curl https://api.homeportfolio.com/v1/property/100030048320 \
  -H "X-API-Key: YOUR_KEY"

UPRN 100030048320 is a real property in Derbyshire — it returns the full 379-field response so you can see exactly what you'll get.

Daily limits reset at midnight UTC. Per-minute limits use a sliding window.

You'll receive a 429 Too Many Requests response with a Retry-After header indicating when your quota resets:

{
  "detail": "Rate limit exceeded. Resets at 2026-03-29T00:00:00Z",
  "retry_after": 3600
}

Build retry logic with exponential backoff. For per-minute limits, wait the number of seconds in retry_after.

Yes — a single key works across all your projects. If you need separate keys per project (for usage tracking), upgrade to Starter (2 keys), Pro (5 keys), or Enterprise (20 keys).

UPRN stands for Unique Property Reference Number — a unique 12-digit identifier assigned to every addressable location in Great Britain by Ordnance Survey. Every property has exactly one UPRN that never changes.

You can find a property's UPRN using our search endpoint:

curl "https://api.homeportfolio.com/v1/search?q=10+Downing+Street+London" \
  -H "X-API-Key: YOUR_KEY"

We cover 36M+ properties across England and Wales using OS Open UPRN as the master address list. Scotland is partially covered. Not all 379 fields will be populated for every property — coverage varies by data source.

Up to 379 fields across 19 intelligence sections. You can request the full response or a specific section:

See the full field reference in the docs.

Each response includes a data_quality section with freshness timestamps per source.

A 404 on /v1/property/{uprn} means we found the UPRN in OS Open UPRN but have no enriched intelligence for it yet. This affects roughly 5% of properties, usually:

• Very new builds (added to address register but not yet in other datasets)
• Non-residential properties (commercial, industrial)
• Remote rural properties with limited data coverage

Use /v1/search?postcode=XX1 1XX to verify the UPRN exists first.

Yes. Not every property has every data point. For example:

• EPC data only exists for properties that have had an energy assessment
• Ownership records may be absent for unregistered land
• Planning applications only exist if applications were submitted nearby

Check the data_quality section in the response for confidence scores and source timestamps.

The free tier includes:

• 50 API calls per day
• Full access to all 379 fields and 19 sections
• All endpoints: property, search, area, compare
• 1 API key
• No credit card required

The only limitation is call volume. The data quality is identical across all plans.

Visit your dashboard, scroll to the Upgrade section, and click the plan you want. You'll be taken to a Stripe checkout page. Your new limits activate immediately after payment.

Yes. Cancel from your Stripe billing portal at any time. Your plan stays active until the end of the current billing period, then automatically downgrades to the free tier (50 calls/day). Your API key and all your data remains accessible.

Yes — annual billing saves 2 months vs monthly:

• Starter: £990/yr (vs £1,188 monthly)
• Pro: £2,990/yr (vs £3,588 monthly)
• Enterprise: £9,990/yr (vs £11,988 monthly)