Decode an EMV transaction dump
You have raw TLV hex from a terminal log or DE55 field and need to understand what happened.
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PayProbe has 80+ tools, guides, and references. Start from what you're trying to do — each workflow below chains the tools in the order you'd actually use them — or jump straight to any page from the full map underneath.
Start from your task
Follow a path step by step, or jump into the middle — every node is a link.
Investigate a declined transaction
A transaction failed and you need to find out why — from the ISO 8583 message down to the response code.
Debug a contactless (NFC) transaction
Working on kernel behavior — what the terminal asked for, what the card answered, and how CVM was decided.
Run a key loading ceremony
Generate key components, combine them, verify KCVs, and wrap the result for distribution.
Verify EMV cryptograms & card security values
Derive keys from the issuer master key, then compute and check ARQC, CVV, and CAVV values.
Work with PIN blocks & verification
Encode PIN blocks, verify PVV or IBM 3624 offsets, and derive DUKPT transaction keys.
Generate test card data
Seed a test environment — cards, magstripe tracks, and full data sets, then validate the results.
Test 3-D Secure & webhooks
E-commerce integration: authenticate with 3DS2, check the CAVV, then verify your webhook handling.
Handle disputes & settlement
From a chargeback notification to the economics: reason codes, simulation, and interchange fees.
Explore stablecoin & x402 payments
HTTP-native payments on crypto rails: learn the protocol, simulate the flow, decode the headers.
Everything on the site
The complete map — every tool, guide, and reference page.
🧰 Tools82 tools
Card Data
EMV & Chip
- EMV TLV Decoder
- EMV TLV Builder
- EMV Tag Reference
- PDOL / CDOL Builder
- TVR Decoder
- AIP Decoder
- IAD Decoder
- CVM List Decoder
- TTQ Decoder
- CTQ Decoder
- Amex Reader Capabilities Decoder
- Kernel 8 Qualifier Decoder
- Mobile CVM Results Decoder
- Card Capabilities Decoder
- TSI Decoder
- AUC Decoder
- ASN.1 / DER Decoder
- POS Terminal EMV Config
- ARQC / ARPC Calculator
- CVV / CVC Calculator
- CAVV Calculator
- CAP Calculator
Cryptography & Keys
Messaging
Reference
Blockchain
📚 Reference
- Standards CheatsheetsEMV, PCI, ISO 8583
- Test Credentialssandbox keys
- NFC PaymentsISO 14443
- QR PaymentsEMV QR
- Country ProfilesISO 3166 / 4217
- Blockchain in Payments