API

Version 1 · OpenAPI · API terms · Terms · Acceptable use

Rental housing law at an address and a date, as JSON. Every rule carries its citation and a link to the official source. Information, not legal advice.

Authentication

Create a key under Account › API keys (needs the API plan). Send it on every request:

Authorization: Bearer ce_<id>_<secret>

We store only a hash of the secret, so we can't show it again. Lost it? Revoke the key and create a new one.

Endpoints

curl -G https://oakrule.com/v1/rules \
  -H "Authorization: Bearer $CE_KEY" \
  --data-urlencode "address=3918 Fulton St, San Francisco, CA" \
  -d date=2026-10-01 -d year_built=1923 -d units=6

curl -G https://oakrule.com/v1/rules -H "Authorization: Bearer $CE_KEY" \
  -d state=NJ -d city=Hoboken -d units=4

curl https://oakrule.com/v1/rent-increase/check \
  -H "Authorization: Bearer $CE_KEY" -H "Content-Type: application/json" \
  -d '{"address": "6238 De Longpre Ave, Los Angeles, CA", "facts": {"year_built": 1964, "units": 12},
       "current_rent": 2000, "new_rent": 2080, "effective_date": "2027-01-01", "notice_date": "2026-11-15"}'

curl -G https://oakrule.com/v1/portfolio/changes -H "Authorization: Bearer $CE_KEY" -d days=365

curl https://oakrule.com/v1/usage -H "Authorization: Bearer $CE_KEY"

curl -OJ https://oakrule.com/v1/dataset/latest/rules.csv -H "Authorization: Bearer $CE_KEY"

Pricing and limits

• $199 a month, including 5,000 calls; then $0.03 per call. Billed monthly by Stripe.
• 120 requests per minute per key. Every answer has X-RateLimit-Limit and X-RateLimit-Remaining; over the limit you get 429 with Retry-After.
• Monthly safety cap of 200,000 calls per organisation. /v1/usage is free.

Errors

Errors are JSON: {"error": {"type": "...", "message": "..."}}. 401 bad or revoked key, 402 the API plan is off, 404 address not found, 422 invalid input or an area we don't cover yet, 429 rate limit, 503 the US Census geocoder did not answer.

Rules dataset

Every reviewed rule as one file, released monthly: rules.csv, rules.json, a JSON schema, a changelog against the previous release and SHA256SUMS. List releases with GET /v1/dataset; latest works in place of a month. Included with the API plan; downloads don't count as calls. Massachusetts is free without a key: /data.

Coverage

California, New Jersey and Massachusetts state law, plus local rules of the cities we list in the app. Outside a covered city you get state law and a note that local rules may add protections.

OpenAPI

Machine-readable description: /v1/openapi.json

Not legal advice. We quote the law from official sources and explain it in plain words. We can't tell you what to do in your situation. For that, talk to a legal aid office, your city's rent office or a lawyer.