Invoice clients for software, web, and maintenance work.

How to invoice web development work

Include the project name, delivery period, invoice number, due date, payment terms, and the agreed currency. If billing hourly, add the number of hours and rate. If billing fixed-fee, use milestone-based descriptions.

When to use a retainer invoice

Use a retainer invoice for recurring maintenance, uptime support, small fixes, monitoring, or advisory availability. Retainers are easier to approve when the scope and billing period are visible.

Developer-specific invoicing considerations

Software development invoices often need to distinguish between different types of work: coding, code review, testing, deployment, and meetings. Be specific in your line item descriptions so the client understands what each charge covers.

For fixed-price projects, break the invoice into milestones tied to deliverables: requirements review, sprint completion, user acceptance testing, and production deployment. This creates natural review points and reduces disputes about what was delivered.

Open source and side project billing

If you contribute to open source as part of a client engagement, track those hours separately. Some clients want to see open source contributions itemized. If the client benefits from open source tools you maintain, you can invoice for maintenance time or include it as part of a retainer.

For side projects that turn into paid work, start invoicing from the moment the scope becomes formal. Even informal agreements benefit from a written invoice as a record of what was agreed and delivered.

Related templates

• Hourly Invoice
• Freelance Invoice
• International Client Invoice
• Consultant Invoice

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