About ISO8583Studio

ISO8583Studio is a free, open-source desktop application for working with ISO 8583 payment messages and the cryptography around them. It bundles nine simulators (five shipping, four in development) and 64 tools: an authorization host you can script, a Thales payShield 10K emulation with 41 documented host commands, an Android terminal emulator, an APDU card session, and calculators for PIN blocks, DUKPT, TR-31, EMV cryptograms, MACs and key check values.

It runs on Windows and macOS as a native installer and builds from source on Linux. It is written in Kotlin Multiplatform with Compose Desktop and released under the GNU AGPL v3. Keys and test data never leave the machine it runs on.

• Simulators: Host, HSM, HSM Command Console, POS and APDU shipping; Switch, Issuer, ATM and ECR in development. All nine.
• Tools: 64 across six disciplines: EMV and card, cryptography, key management, PIN and payment utilities, MAC, data converters. Documentation.
• Release: v1.0.14 · Jun 12, 2026 · installers are v1.0.0 · every version.
• License: GNU AGPL v3 — free to use, study, modify and redistribute; no trial, no seat limit. Read the licence.

Most of a payment engineer's day is spent waiting for something that is not code: a test host that is down, a lab slot three weeks out, a scheme contact who has not replied, a physical HSM that someone else is using. The integration itself is usually a few hundred lines; proving it is the hard part.

The studio moves that proof onto the engineer's own laptop. Stand up an authorization host, point a terminal at it, send a 0200, script the 0210, verify the cryptogram against a simulated payShield, and read every field beside the hex it came from. The lab is still needed at the end, but it is the end, not the middle.

Everything in it is documented to the byte, because a tool that hides what it is doing is no use for debugging a transaction that one bank parses differently from another.

The studio is published by AiCortext Solutions Pvt. Ltd., India, which also offers EMV certification, payment middleware, kernel development and hosted simulators built on the same engine. AiCortext Solutions is the data controller for the website and the application; the privacy policy and terms name it.

1. Jan 2025The first guides are published: ISO 8583 message format, bitmaps and response codes.
2. May 2025v1.0.0, the first public release: Host and HSM simulators, cipher tools, REST gateway mode and YAML configuration import and export, with Windows and macOS installers.
3. Apr 2026v1.0.7 adds the HSM Command Console, a host-command client for payShield, Futurex, Luna, Utimaco and nShield.
4. Jun 2026v1.0.14, the current release: payShield M4 and GW host-command fixes in the HSM simulator.

Release notes for every version are on the versions page; the roadmap is on GitHub.