Muhammad Saad
Independent software developer · Karachi, Pakistan · Writing under the name SaadDev for Techorphic
I have been writing software for about twelve years and freelancing on and off for most of that time. The work has been split between client projects (a lot of internal tools, a few mobile apps, the occasional WordPress disaster I inherited and had to talk down off a ledge) and small products of my own. InvoiceWithMe is one of the latter.
I have invoiced clients in roughly eight countries, in five currencies, through more payment platforms than I can comfortably remember. Some of those invoices got paid the same day; some took ten weeks and three follow-up emails. The guides and blog posts on this site come out of that experience — not from reading a stack of accounting textbooks but from getting things wrong, fixing them, and writing down what worked the second time.
I am not an accountant and nothing on this site is accounting or legal advice. Where I cite tax rules, they are written in plain English and pointed at official sources (IRS, HMRC, CRA, ATO, the EU VAT directive). If you are about to make a decision with real money attached, please cross-check with a professional in your jurisdiction.
Where to find me
- Email: saad@techorphic.com
- GitHub: github.com/saad-89
- LinkedIn: linkedin.com/in/muhammadsaad89
- X (Twitter): @saadkashmiri_
- Studio: techorphic.com
My approach to these articles
Every guide on this site goes through three passes before it ships. First I draft it from memory, which catches the things I actually care about. Then I check the specifics: tax rates, statutory interest figures, the exact wording of the EU reverse-charge phrase, what an HMRC VAT number actually looks like in 2026. The third pass is the cruel one — I cut anything that sounds like it was written for traffic instead of for someone who has the problem in front of them right now.
If you spot an error, please email me. Corrections get published within a few days and the article's updated date moves forward.
Articles by me on this site
- How to write an invoice — the complete 2026 guideGuide
- What does Net 30 actually mean?Guide
- Invoice vs receipt vs billGuide
- How to invoice as a freelancer (US/UK/CA basics)Guide
- International invoicing — VAT, GST, reverse chargeGuide
- Following up on unpaid invoicesGuide
- Invoice numbering conventions that scaleGuide
- Getting paid faster — 12 terms that workGuide
- Why I built another invoice generator in a saturated marketBlog
- Why this invoice tool doesn't ask you to sign upBlog
- Should you charge a late fee?Blog
- Stripe vs PayPal vs WiseBlog
- The history of the invoiceBlog