{"name":"Building Safety Levy (BSL) Fees API","description":"Serves Building Safety Levy rates by local authority (England), and calculates the levy charge for a given development, based on gov.uk guidance.","source":"https://www.gov.uk/guidance/building-safety-levy-guidance/section-2-levy-rates-and-calculations","retrievedAt":"2026-07-27","localAuthorityCount":298,"endpoints":{"GET /rates":"List all local authority levy rates (includes AddressBase custodianCode). Supports ?q= to filter by name.","GET /rates/:localAuthority":"Get the levy rate for one local authority (by name or slug).","GET /custodian-code/:code":"Get the levy rate for the local authority matching an AddressBase Local custodian code (AUTH_CODE).","GET /calculate":"Calculate the levy fee. Query params: localAuthority (or custodianCode), floorspace (m2, per plot), plots (optional, default 1), previouslyDevelopedLand (true/false). Returns feePerPlot and totalFee.","GET /meta":"Metadata about the dataset (source, units, notes, last retrieved date)."}}