I'm running several SI projects at once — do I really need to keep tax invoices for each client separately?
Running multiple SI projects at once without separately managing tax invoices or withholding receipts per client is the single most common mistake in the field, leading to some income being left out when you file comprehensive income tax. Cloud server costs like AWS or GCP used for business purposes are recognized as necessary expenses, so organizing revenue and expense documentation project by project is essential for an accurate filing — and if your revenue scale grows, it's also worth considering converting to business registration.
Income Structure Features for Backend Developers
Key Necessary Expense Items
Tax Advantages for Backend Developers
The role most directly tied to the R&D tax credit
Designing new service architecture or developing logic to handle high-volume traffic is exactly the kind of work that tends to qualify as personnel costs eligible for the R&D and human resource development tax credit.
Linking to venture business certification
If you've built the backend for a tech-based service in-house, you can also review corporate and acquisition tax reductions through venture business certification.
Spreading out revenue timing for high-value projects
For short-term, high-value projects, we help coordinate the timing of income to manage your progressive tax bracket.
The Most Common Mistake in the Field
Running multiple SI projects at once without separately managing tax invoices or withholding receipts per client often means some income gets left out when filing comprehensive income tax.
A Must-Check for On-Site Freelancers — Disguised Subcontracting & Employee Status
Even if your contract says freelancer, you may be judged an employee based on your actual working reality
A work reality resembling employment carries disguised-subcontracting risk
If you work on-site at an SI project with fixed working hours, direct work direction and attendance management from the client, and use of the client's in-house development environment and equipment, your actual status may be judged as an employee even if your contract says freelancer. If disguised subcontracting is found, it can lead to retroactive four-major-insurance enrollment and back taxes on employment income.
Work autonomy needs to be preserved to stay safe
A structure where you contract based on scope of work and deliverables (like completed API development or a deployment) and can decide your own detailed working methods and hours keeps a freelance (business income) contract safe.
Frequently Asked Questions
Related Roles Worth a Look
Frontend Developer
The developer who builds the screens, buttons, and UI users see and interact with
Full-Stack Developer
A developer who handles both frontend and backend to build the entire service
Database Administrator (DBA)
A specialist responsible for database design, operation, performance tuning, and security