Multi-Platform E-Invoice Extension

I am preparing an e-invoice extension for the Zoho Books, Xero, and QuickBooks marketplaces and need a developer who can take the project from concept to approved listing. The core purpose is to let our users create invoices automatically and have taxes calculated correctly every time, no matter which of the three ecosystems they work in.

Key scope
• Platforms: Zoho Books, Xero, QuickBooks
• Functions: automated invoice generation and precise tax calculation
• User access: Administrators, Accountants, and Sales Team must each see only the controls relevant to their role.

Technical expectations
The add-on should rely on each platform’s official SDK or REST API, respect rate limits, and follow their branding and security guidelines so that it passes marketplace review without rework. Clean, well-commented code, unit tests, and concise setup documentation are essential. Where features overlap across platforms, aim for a shared core with adapters to keep maintenance efficient.

Deliverables
1. Source code in a private Git repository
2. Step-by-step deployment guide and user manual
3. Video walkthrough showing the extension running in all three platforms
4. Submission packages ready for each marketplace, including required assets and compliance checklists
5. Thirty days of post-launch support for bug fixes

Acceptance criteria
• An invoice can be generated in under five seconds from a sales order on any of the three systems.
• Tax totals match each platform’s native calculation for identical data sets.
• Role-based permissions prevent cross-role data or action leakage.
• Marketplace reviewers approve the listing on first submission.

If you have certified experience with at least two of these platforms and are confident you can meet the review guidelines, let’s discuss timelines and milestones.