GST Billing Software

I need a web-based GST billing software similar to Vyapar and Mybillbook, accessible on both desktop and mobile. Ready made is OK.

Essential Features:
- GST Invoicing
- Client Management
- GST Filing

Ideal Skills:
- Experience in developing web-based billing software
- Familiarity with GST regulations
- Strong UI/UX design for seamless desktop and mobile experience
- Proficient in backend development to ensure data security and integrity

Please provide examples of similar work done.