# Paytools — Payment Protocol Toolbox

> Payment Protocol Toolbox (iPhone/iPad app by Emin Mammadov.)

- Source: https://appshunter.io/ios/app/paytools/id6791676893 (this page in markdown: same URL + `.md`)
- Developer: [Emin Mammadov](https://appshunter.io/developer/1806929744)
- Category: Developer Tools, Utilities
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 4 MB
- Languages: American English
- Released: 2026-07-23
- Data updated: 2026-09-06
- User reviews in markdown: https://appshunter.io/ios/app/paytools/id6791676893/reviews.md

## What is Paytools?

Paytools is an offline payment-engineering workbench for developers, QA engineers, integrators, students, and fintech teams.

Decode and inspect common payment-message structures, explore field definitions, convert technical data, and keep essential payment references close at hand. Processing happens locally on your device, so pasted messages and imported files are not uploaded to a server.

PAYMENT TOOLS

• Inspect ISO 8583 MTIs, bitmaps, and present data elements
• Decode and build primary and secondary bitmaps
• Parse BER-TLV data and identify common EMV tags
• Recognize SWIFT MT blocks and ISO 20022 XML messages
• Convert between HEX, ASCII, decimal, binary, and packed BCD
• Validate synthetic card numbers with the Luhn algorithm
• Compose synthetic Track 2 and ISO-0 PIN-block test data
• Use development utilities for XOR and DES odd parity

FILE LAB

Open payment interchange files locally and produce a readable record or offset-preserving hexadecimal view. File Lab helps engineers orient themselves in Mastercard IPM, Visa CTF/Base II candidates, fixed-width exports, and other scheme or IPS files while preserving unknown bytes.

KNOWLEDGE LIBRARY

• Search all 128 ISO 8583 data elements
• Learn ISO 8583:1987, 1993, and 2003 MTI concepts
• Follow authorization from merchant to acquirer, scheme, and issuer
• Understand STIP, advice, reversal, clearing, and settlement flows
• Review ISO 20022 message families and validation concepts
• Study EMV transaction and cryptogram terminology

CODES AND FIELDS

Search operational response-code references for common ISO profiles, Visa, Mastercard, UnionPay/UPI, 3-D Secure, and gateway HTTP outcomes. Open any ISO field for its purpose, format, and implementation notes, including an expanded guide to DE22 POS Entry Mode.

PRIVATE BY DESIGN

Paytools has no account requirement and no cloud processing. Use synthetic or appropriately masked test data. Production payment formats and code meanings can vary by network, region, product, and specification release.

Paytools is an independent educational and development utility. It is not affiliated with or endorsed by any payment network. Formal certification and production processing require the current authorized specifications, test packs, approved cryptographic systems, and applicable security controls.


## Version history (last 1 release)

### 1.0 — 2026-07-23

No release notes.

## More apps by Emin Mammadov

- [DrmCatcher](https://appshunter.io/ios/app/drmcatcher/id6748619797)
- [NetGlance: Network Speed](https://appshunter.io/ios/app/netglance-network-speed/id6787721630)

All apps by Emin Mammadov: https://appshunter.io/developer/1806929744

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-06.*