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Invoices for Software Developers: Hourly Rates, Sprints, and Maintenance Contracts

How software developers should write professional invoices: Hourly rates, project packages, agile billing, and maintenance contracts explained.

Thomas Richter · ·13 min read

As a software developer or programmer, you work with different billing models: hourly rates, project packages, sprint-based billing, or maintenance contracts. The right choice depends on project type and client relationship.

The Specifics of Developer Invoices

Software development has specific requirements:

  • Complex projects: Often hard to estimate
  • Agile methods: Sprint-based billing
  • Maintenance & support: Ongoing care after launch
  • Licenses & tools: Passing on third-party costs
  • Source code handover: When and how?

Billing Models for Developers

1. Hourly Rate (Time & Material)

Standard for consulting and flexible projects.

Typical Hourly Rates by Specialization:

AreaJuniorSeniorExpert
Frontend (React, Vue)€60-80€80-120€120-160
Backend (Node, Python)€65-85€85-130€130-180
Mobile (iOS, Android)€70-90€90-140€140-200
DevOps/Cloud€75-100€100-150€150-220
Machine Learning€80-110€110-170€170-250
Blockchain€90-120€120-180€180-280

2. Sprint-Based Billing

For agile projects with Scrum or Kanban.


Sprint Billing:

Sprint Duration: 2 weeks
Team: 1 Senior Developer
Capacity: 8 work days × 8h = 64h

Sprint Price:
64 hours × €110                         €7,040.00

Or as flat sprint:
Sprint Package (2 weeks):               €6,500.00
(incl. Planning, Daily, Review, Retro)

3. Fixed-Price Projects

For clearly defined, manageable projects.


Typical Fixed Prices:

Landing Page:                     €2,000-5,000
Company Website:                  €5,000-15,000
E-Commerce Shop (Standard):      €10,000-30,000
Mobile App (simple):             €15,000-40,000
SaaS MVP:                        €30,000-80,000

4. Maintenance Contract (Retainer)

For ongoing support after project launch.


Maintenance Contract:

Monthly Retainer "Standard"            €890.00

Includes:
- Up to 8 hours support/month
- Security updates
- Monitoring & alerting
- Bug fixes (critical)
- Weekly backups

Additional hours: €120/hr
Unused hours expire.

Sample Invoice Hourly Rate


INVOICE No. 2025-DEV-089

Client: Innovation Labs GmbH
Project: API Integration CRM System

Service Period: October 2025

Item 1: Backend Development
REST API development and testing
42.5 hours × €110                      €4,675.00

Item 2: Code Review & Documentation
5 hours × €110                           €550.00

Item 3: Deployment & DevOps
CI/CD pipeline setup, staging environment
8 hours × €110                           €880.00

─────────────────────────────────────────────────
Total hours worked: 55.5 hrs

Net amount:                            €6,105.00
plus 19% VAT:                          €1,159.95
─────────────────────────────────────────────────
Total:                                 €7,264.95

Payable within 14 days.

Time record see attachment.

Sample Invoice Sprint Billing


INVOICE No. 2025-DEV-090

Client: StartUp Dynamics AG
Project: SaaS Platform "TaskFlow"

Sprint 5: Oct 14 - Oct 25, 2025

Item 1: Sprint Package
2-week sprint (Full-Stack Development)
incl. Planning, Dailies, Review
Fixed:                                 €6,800.00

Completed Features:
- User Dashboard (Frontend)
- Notification System (Backend)
- Email Integration
- Performance Optimization

Item 2: Additional Meetings
3 × 1h stakeholder meetings
3 hours × €110                           €330.00

─────────────────────────────────────────────────
Net amount:                            €7,130.00
plus 19% VAT:                          €1,354.70
─────────────────────────────────────────────────
Total:                                 €8,484.70

Next Sprint: Oct 28 - Nov 8, 2025

Sample Invoice Fixed Price


INVOICE No. 2025-DEV-091

Client: Handwerk Meister GmbH
Project: Company Website Relaunch

Payment Schedule:

Total Project (Fixed Price):          €12,500.00

Already Paid:
- Deposit (50%):                      -€6,250.00
  (Invoice 2025-DEV-078 dated Sep 1, 2025)

This Invoice: Final Invoice

Item 1: Remaining Project Balance
50% upon acceptance:                   €6,250.00

Deliverables:
- Responsive website (15 pages)
- CMS integration (WordPress)
- Basic SEO optimization
- Contact forms
- Cookie consent
- 2 weeks support after launch

─────────────────────────────────────────────────
Net amount:                            €6,250.00
plus 19% VAT:                          €1,187.50
─────────────────────────────────────────────────
Total:                                 €7,437.50

Acceptance was on Oct 20, 2025.

Billing Licenses and Tools

Pass on third-party costs transparently:


Item: Passed-Through Licenses

Server Costs (AWS/Hetzner):
Monthly costs October:                   €156.80

Domain Registration:
example.de (1 year):                      €12.00

Premium Plugin (one-time):
WooCommerce Extension:                    €89.00

Email Service (monthly):
SendGrid Business:                        €45.00
─────────────────────────────────────────────────
Third-party costs total:                 €302.80

Note: Third-party costs are passed through
without markup.

Regulating Source Code Handover


Notes on Source Code Handover:

Upon payment of this invoice, the client receives:
- Complete project source code
- Documentation (README, API docs)
- Repository access credentials (GitHub/GitLab)
- Deployment instructions

Not included:
- Self-developed libraries/frameworks
- Reusable components
  (these remain with the developer)

Copyright of source code transfers to
client upon payment.

Billing Maintenance Contracts


INVOICE for Maintenance Contract

Service Period: November 2025

Item 1: Monthly Maintenance Contract
Package "Premium"                        €890.00

Included Services:
- Security updates performed
- Server monitoring (99.9% uptime)
- Backup verification
- Performance optimization

Item 2: Support Hours Used
6.5 of 8 hours used
(Checkout bug fix, feature adjustment)
Included in contract:                      €0.00

Item 3: Additional Hours
3 hours × €120 (over quota)              €360.00
(Feature: PDF export implemented)
─────────────────────────────────────────────────
Net amount:                            €1,250.00
plus 19% VAT:                            €237.50
─────────────────────────────────────────────────
Total:                                 €1,487.50

Remaining hours: 1.5 (expire Nov 30)

Common Mistakes in Developer Invoices

1. Scope creep not caught

Problem: Project grows without additional pay Solution: Document and price change requests

2. No time tracking

Problem: Discussion about hours Solution: Use tools like Toggl, Harvest; attach records

3. Maintenance given away

Problem: Free support after launch Solution: Maintenance contract or support hourly rate

4. Third-party costs not passed on

Problem: Servers, licenses out of pocket Solution: Pass through transparently

5. Milestones not agreed

Problem: Risk on large projects Solution: 50% start, 25% middle, 25% end

VAT for Developers

Regularly taxable

Software development is subject to 19% VAT.

EU Clients with VAT ID


Reverse charge applies according to
§ 13b UStG.
Client VAT ID: ATU12345678

Third-Country Clients


Tax-free service according to
§ 3a para. 2 UStG.

Conclusion

A professional developer invoice is transparent, traceable, and sets clear expectations for scope and support.

Key points:

  1. Time tracking - Attach detailed documentation
  2. Define scope - Bill change requests separately
  3. Regulate maintenance - Support after launch costs money
  4. Milestones - Payment schedule for large projects
  5. Pass through licenses - Show third-party costs transparently

With Clever Invoice, you create developer invoices in minutes - including time tracking import and sprint templates.

Frequently asked questions

Hourly rate or fixed price - which is better?

Fixed price only for clearly defined, manageable projects with stable scope. Hourly rate for everything else, especially agile projects or when requirements may change. Combination possible: Fixed price for base, hourly rate for extras.

How do I handle scope creep?

Document and price every change to the original scope as a change request. Communicate: "This goes beyond the agreed scope, costs X hours." Only implement after written approval. No "let's quickly add this too".

Who owns the source code?

Basically the developer (copyright). With payment, usage rights or full ownership can transfer - this must be regulated in the contract. Self-developed libraries often remain with the developer.

How do I calculate a fixed price?

Estimate effort (hours) × hourly rate + buffer (20-30% for unforeseen issues) = fixed price. The less clear the requirements, the more buffer. Or: Define and limit scope clearly (e.g., "3 revision rounds").

What belongs in a maintenance contract?

Hour quota, included services (updates, monitoring, backups), response times, costs for overages, cancellation notice. Typical: 4-10 hours/month, critical bugs prioritized, feature requests extra.

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