{"country":"gb","currency":"GBP","name":"United Kingdom","taxYear":2026,"taxYearPeriod":"April 2025 - April 2026","description":"UK Self-Employed Income Tax, Class 4 NIC, Student Loan Calculator","parameters":{"income":{"type":"number","required":true,"description":"Annual gross income GBP"},"incomePeriod":{"type":"string","default":"yearly","options":["monthly","yearly"]},"region":{"type":"string","default":"england","options":["england","scotland"]},"studentLoan":{"type":"string","default":"none","options":["none","plan1","plan2","plan4","plan5","postgrad"]},"vatRegistered":{"type":"boolean","default":false,"description":"VAT registered (20%)"},"weeklyHours":{"type":"number","default":40,"description":"Weekly working hours"},"paidDaysOff":{"type":"number","default":28,"description":"Annual leave days"}},"example":"/v1/calculate/gb?income=50000"}