Invoice clients for API development, database work, and server architecture. Fast, professional invoices from Tidybill.
A backend developer invoice covers work on server-side systems, APIs, databases, and infrastructure logic that powers applications. Backend developers write the code that processes data, handles authentication, manages business logic, and communicates with databases and external services. Common billable work includes REST or GraphQL API development, database schema design and optimisation, server configuration, integration with third-party services, security implementations, and performance tuning. Invoices often reference specific endpoints, services, or system components to help clients understand what was built. Backend work is frequently billed hourly or on a sprint basis, though fixed-price project invoicing is common for well-scoped deliverables like a payment integration or authentication system. Including performance benchmarks or test coverage summaries as invoice notes adds transparency and demonstrates value.
| Service | Typical Rate | Unit |
|---|---|---|
| Backend development (hourly) | 75 | hour |
| REST API development | 1200 | project |
| Database design and migration | 600 | project |
| Third-party API integration | 500 | integration |
| Security audit and hardening | 800 | project |
| Monthly server maintenance retainer | 400 | month |
Invoice at the end of each sprint or billing period with a summary of what was delivered. For hourly work, attach a timesheet grouped by day and task. For fixed-price deliverables, describe what was built and reference any acceptance criteria from the contract. If infrastructure or cloud costs are passed through, list them separately with the provider invoice attached. Net 14 or net 30 payment terms are standard. For long projects, milestone billing at the end of each defined phase keeps cash flow predictable and reduces the risk of a large unpaid invoice at project end.