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Technical specifications for Import Control System Northern Ireland for software developers.
The Customs Handling of Import and Export Freight (CHIEF) system is supported by detailed user guides for trade users. For Direct Trader Input to CHIEF and Inventory system linking we have the Technical Interface Specification guides.
Technical specifications for developing software to send information to Companies House digitally.
Data submission specifications for the children looked after (CLA) return for 2022 to 2023.
Technical specifications for New Computerised Transit System (NCTS) software developers.
Read Income Tax guidance for software developers working with payroll software.
Minimum technical specification for manufacturers of chargepoint units for residential properties covered by OZEV chargepoint grant schemes.
Use this technical documentation for individual returns if you're a software developer working with the Self Assessment online service.
National Insurance guidance for software developers working with payroll software.
Returns technical specifications for Self Assessment Online software developers.
Data submission specifications for the children looked after (CLA) return for 2024 to 2025.
Use this technical documentation for individual returns if you're a software developer working with the Self Assessment Online service.
Real Time Information (RTI) Rules and Interface Management (RIM) artefacts and supporting technical specifications for software developers.
Data submission specifications for the children looked after (CLA) return for 2021 to 2022.
Individual returns technical specifications for Self Assessment Online software developers.
Use this technical documentation for partnership returns if you’re a software developer working with the Self Assessment online service.
Use this guidance for support if you're a software developer working with the Self Assessment Online service.
Don’t include personal or financial information like your National Insurance number or credit card details.
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