
Omni Calculator
calculator.net
Build vs. Buy Calculator
DeveloperToolStack
DevNestTools
DevTools Advanced
DevTools.fit
Free, no-signup calculators for the money side of building software and freelancing

VatStack
vatlayer API
Taxid.dev
VIESAC
Lookuptax
VATnode.dev
The VAT API
Justaxit validates lists of EU VAT, UK EORI and South African VAT numbers in bulk against VIES, HMRC and SARS, returning company names, addresses and exportable results.

Which is more popular?
Website, pricing, platforms and company facts side by side.
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|---|---|---|
| Website | devfinancetools.com | app.justaxit.com |
| Pricing | ||
| Company | 2026 | Startup from Poland · 1 - 9 employees |
| Listed in |
In their own words, as submitted to SaaSHub.


DevFinanceTools is a collection of free, no-signup calculators for the money side of building software and freelancing. Everything runs in your browser — no account, no tracking beyond basic page-view analytics — and every tool shows its formulas and benchmarks so you can check the maths...
Checking a supplier list against the EU VIES website means pasting one VAT number at a time, waiting, copying the result back into Excel, and repeating it a few hundred times. Justaxit turns that into one paste and one click. Paste a column of VAT numbers straight from Excel and Justaxit...
What each product offers, as listed by its team.


How often each product is chosen within a category, 0–100% relative to the other.


Share your experience with using DevFinanceTools and Justaxit. For example, how are they different and which one is better?
When comparing DevFinanceTools and Justaxit, you can also consider the following products.

Helping you make rational decisions, one calculation at a time.
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Simplify VAT & GST for your digital business.
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Online calculator for quick calculations, along with a large collection of calculators on math, finance, fitness, and more, each with related in-depth information.
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Free VAT Validation & EU VAT Rates API
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Should you build an internal tool? Or just buy it?
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TaxID is a developer-first API to validate VAT and tax IDs across 31 countries — 27 EU member states via VIES, plus UK, Switzerland, Norway, and Australia. Stripe-style errors, JSON responses, 100 free validations/month.
Compare Taxid.dev to DevFinanceTools or Justaxit: