Payment Testing Tools
Every tool you need,
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89 free, browser-based payment tools — 45 stable, 44 beta — across card data, EMV & chip, cryptography, and messaging. No signup required.
Card Validator
Validate payment card numbers using the Luhn algorithm. Detects Visa, Mastercard, Amex, Discover, UnionPay, and more.
IBAN Validator
Validate IBAN numbers, extract BBAN, check digit, country code, and verify SEPA routing information.
Amount Formatter
Format and validate payment amounts using ISO 4217 minor unit rules. Avoid common decimal precision bugs.
Luhn Algorithm
Standalone Luhn check for any numeric string. Step-by-step calculation trace, digit-level breakdown.
Test Card Generator
Generate valid test card numbers for all major schemes covering specific decline, 3DS, and authentication scenarios.
Track 1 & 2 Generator
Generate ISO 7813 Track 1 and Track 2 magnetic stripe data from card details, with LRC computation and parse mode for decoding existing tracks.
Card Data Generator
Generate complete sets of test card data — PAN, expiry, CVV, Track 1 & 2, EMV data — for database seeding.
EMV TLV Decoder
Decode TLV-encoded hex bytes (e.g. DE55 field) into a structured, annotated list of EMV tag/length/value records.
EMV TLV Builder
Construct EMV TLV hex strings from tag/value pairs. Supports nested constructed tags and BER-TLV encoding.
EMV Tag Reference
Search the full database of EMV tag definitions by tag ID or keyword — descriptions, formats, and length constraints.
PDOL / CDOL Builder
Parse PDOL and CDOL templates, fill in terminal/card values, and build the response data hex for EMV transaction testing.
TVR Decoder
Decode the Terminal Verification Results (tag 95) 5-byte bitfield into human-readable flag descriptions.
AIP Decoder
Decode Application Interchange Profile (tag 82) to show which EMV functions are supported by the card.
IAD Decoder
Decode Issuer Application Data (tag 9F10) for Visa, Mastercard, Amex, and other network-specific formats.
CVM List Decoder
Parse and explain Cardholder Verification Method list (tag 8E) — priority rules for PIN, signature, and no-CVM.
TTQ Decoder
Decode Terminal Transaction Qualifiers (tag 9F66) — what a contactless reader supports and requires.
CTQ Decoder
Decode Card Transaction Qualifiers (tag 9F6C) — the card's contactless requirements returned to the terminal.
Amex Reader Capabilities Decoder
Decode Amex ExpressPay Enhanced Contactless Reader Capabilities (tag 9F6E), the Kernel 4 reader bitmap used in place of the TTQ.
Kernel 8 Qualifier Decoder
Decode the EMVCo Kernel 8 Kernel Qualifier (tag 9F2B) — version, local-authentication flag, and secure-channel / certificate algorithm suite indicators.
Mobile CVM Results Decoder
Decode the Amex ExpressPay Mobile CVM Results (tag 9F71) — whether on-device cardholder verification was performed, required, and its result.
Card Capabilities Decoder
Decode the EMVCo Kernel 8 Card Capabilities Information (tag 9F810D) — the card's supported interfaces and cardholder-verification methods.
TSI Decoder
Decode Transaction Status Information (tag 9B) — the functions the terminal and card actually performed during a transaction.
AUC Decoder
Decode Application Usage Control (tag 9F07) — the issuer's rules for where and how the card may be used.
ASN.1 / DER Decoder
Decode ASN.1, DER, and BER encoded binary structures — useful for certificate and key data in payment systems.
POS Terminal EMV Config
Reference for EMV tags and parameters required in POS terminal configuration — per payment scheme (Visa, Mastercard, Amex, JCB, Discover, UnionPay) and contactless kernel.
ARQC / ARPC Calculator
Compute and verify EMV application cryptograms for CVN10, CVN18, and Mastercard mChip personalisation profiles.
CVV / CVC Calculator
Calculate CVV, CVC, iCVV, CVV2, CVC2, and dCVV values from card data and keys — covers all major card scheme variants.
CAVV Calculator
Calculate and decode Cardholder Authentication Verification Values (CAVV) and AAV for 3D Secure transactions.
CAP Calculator
Generate Chip Authentication Programme (CAP / DPA) codes using emulated Visa or Mastercard card and reader logic.
DES / 3DES Calculator
Encrypt and decrypt hex data using DES and Triple DES with ECB and CBC modes. Essential for payment key derivation and PIN encryption.
AES Calculator
Encrypt and decrypt data using AES-128, AES-192, and AES-256 in ECB, CBC, CTR, and GCM modes.
MAC Calculator
Calculate retail payment MACs using ISO 9797 algorithms — MAC1, MAC2, and CMAC for transaction authentication.
HMAC & SHA Hashes
Compute HMAC-SHA256, HMAC-SHA512, SHA-1, SHA-256, and SHA-512 of hex or text input for message integrity checks.
KCV Calculator
Compute Key Check Values for 3DES and AES keys by encrypting zero data. Essential for key loading ceremonies and HSM validation.
Key Block Decoder
Parse and inspect TR-31 and AS2805 key blocks — header, algorithm, usage, exportability, and key check value.
TR-31 Key Block
Explore the TR-31 key block standard — interactive decoder, structure diagram, field reference, and use cases for HSM key distribution.
TR-34 Key Distribution
Understand TR-34 asymmetric key transport — interactive 2-pass and 1-pass protocol diagrams, CMS token structure, and real-world use cases.
TR-34 Protocol Diagram
Interactive TR-34 key transport diagram — configure KRD/KDH names, key usage, algorithm, and RKRD nonce; the sequence diagram and KTKDH token formula update live.
HSM Key Composer
Compose HSM component keys, compute Key Check Values (KCV), and verify key parity for key loading ceremonies.
Keyshare Generator
Generate test key components of various lengths, split into custodian shares, and compute individual KCV values.
UDK Calculator
Derive Unique Derived Keys (UDK) from an Issuer Master Key and PAN/PAN Sequence Number for EMV personalization.
PIN Block Encoder / Decoder
Encode and decode ISO 9564 Format 0, 1, 2, 3, and 4 PIN blocks. Supports 3DES and AES encryption with step-by-step breakdown.
PIN Verification (PVV)
Calculate and verify Visa PIN Verification Values. Supports PVV generation and offline PIN validation for test cards.
PIN Verification (IBM 3624)
Calculate and verify IBM 3624 PIN offsets used in legacy PIN management and Interac-style PIN derivation.
Payment Authorization Flow
Step through a complete card payment as an animated sequence diagram — authorization, clearing, and settlement — for both card-present and e-commerce (3-D Secure) flows.
ISO 8583 Parser
Parse and build ISO 8583 financial messages with configurable field formats, bitmap decoding, and DE55 expansion.
ISO 8583 Bitmap Decoder
Decode primary, secondary, and tertiary ISO 8583 bitmaps into the list of present data elements.
ISO 8583 DE Reference
All 128 ISO 8583 data elements — format, length, and usage, with a detail page per DE covering subfields, example values, and network dialect notes.
SWIFT MT / MX Validator
Validate, parse, and convert ISO 20022 (MX) and ISO 15022 (MT) SWIFT messages with field-level error highlighting.
IPM & CTF Decoder
Parse Mastercard IPM and Visa CTF clearing files — decode transaction records, field flags, and message structures.
ISO 20022 Message Reference
CBPR+ / HVPS+ ISO 20022 payment messages — pacs, pain, camt — with MT equivalents, key elements, and the November 2026 native-MX migration milestones.
Response Code Reference
Searchable reference of all ISO 8583 DE39 response codes — name, description, category, and retry guidance for each code.
Julian Date Converter
Convert between Gregorian and Julian date formats used in Mastercard IPM settlement files and ISO 8583 fields.
3DS2 AReq / ARes Decoder
Build EMV 3DS (3DS2) authentication requests and decode AReq/ARes messages — transStatus, ECI, reason codes, and challenge flow explained field by field.
BIN Lookup
Identify card issuer, brand, country, and card type (credit/debit/prepaid) from the first 6–8 digits of any card number.
MCC Lookup
Look up ISO 18245 Merchant Category Codes with descriptions, associated card network names, and transaction context.
Currency & Country Codes
Browse ISO 4217 currency codes with minor units and ISO 3166 country codes used in payment transaction fields.
RID & AID Catalog
Searchable catalog of EMV Registered Application Provider Identifiers (RID) and Application Identifiers (AID) by code, scheme, provider, or country.
APDU Response Codes
Look up ISO 7816 / EMV APDU status words (SW1 SW2) like 9000, 6A82, 6985 — category and description, with an instant status-word decoder.
Service Code Decoder
Decode the 3-digit magnetic-stripe service code (ISO 7813) from Track 1 / Track 2 — interchange, authorisation, and PIN/usage rules.
POS Entry Mode Decoder
Decode ISO 8583 DE22 POS entry mode and EMV tag 9F39 — PAN capture method (chip, contactless, magstripe, manual, fallback) and PIN capability.
Chargeback Reason Codes
Complete Visa, Mastercard, and Amex chargeback reason code reference with time limits, pre-arb deadlines, and required evidence.
Interchange Rate Estimator
Estimate Visa and Mastercard interchange fees based on card type, channel, MCC, and amount. Includes scheme assessment fee breakdown.
VAMP Ratio Calculator
Compute your Visa Acquirer Monitoring Program ratio from TC40 fraud and dispute counts against the 2026 merchant and acquirer thresholds.
Payment Crypto Glossary
Comprehensive reference of cryptographic terms in payment networks — key hierarchy, EMV cryptograms, DUKPT, HSM infrastructure — with a big-picture network map.
Blockchain & Payments Glossary
Comprehensive reference for blockchain concepts in payments — consensus, smart contracts, stablecoins, CBDCs, Lightning, cross-border rails, standards, and use cases — with an ecosystem map.
Wallet Address Validator
Validate Bitcoin (P2PKH, P2SH, Bech32), Ethereum, Solana, XRP, and Stellar wallet addresses — checksum, format, and network detection.
Blockchain Tx Decoder
Decode raw Bitcoin and Ethereum transaction hex — inputs, outputs, scripts, signatures, EVM calldata, and ABI-encoded function calls.
CBDC Flow Simulator
Simulate retail and wholesale CBDC payment flows — token issuance, P2P transfer, offline payment, and cross-border multi-CBDC settlement.
Calldata & EIP-712 Decoder
Decode EVM calldata into a readable function call, or parse EIP-712 typed data and compute its type hash, domain separator, and signing digest — all keccak-256 hashing runs in your browser.
Approval & Address Risk Checker
Validate an EVM address (EIP-55 checksum), flag burn and known contracts, or paste an approval’s calldata to catch unlimited allowances and operator grants — fully in your browser.
Transaction Simulator
Decode an Ethereum transaction’s intent locally, then optionally simulate it against an RPC you provide to preview success, revert reason, and gas before signing.
Stablecoin Reference
Regulated stablecoins used for card-network settlement — issuer, chains, contract addresses, decimals, regulation, and Visa / Mastercard settlement support, with a per-coin detail page.
x402 Flow Simulator
Step through the x402 payment protocol over HTTP — the 402 quote, EIP-3009 payment signature, facilitator verify/settle, and delivery — plus failure, facilitator-less, and agent-discovery variants.
x402 Header Decoder
Decode and build x402 protocol headers — PAYMENT-REQUIRED, PAYMENT-SIGNATURE, PAYMENT-RESPONSE (and v1 X-PAYMENT) — with amounts, networks, and EIP-3009 authorizations annotated.
AP2 Mandate Decoder
Decode Agent Payments Protocol (AP2) Intent, Cart, and Payment mandates — the signed verifiable credentials behind agent-initiated purchases — with field explanations and structural checks.
AP2 Flow Simulator
Step through an Agent Payments Protocol purchase — human-present (CartMandate) and human-not-present (IntentMandate) — from shopping prompt through mandate signing to authorization with agent-presence signals.
HEX ↔ ASCII Converter
Convert freely between hexadecimal, ASCII text, and binary representations — essential for payment message debugging.
Base64 Encoder / Decoder
Encode and decode Base64 and Base64URL strings. Useful for API payloads, certificate data, and token inspection.
BCD / Hex / Decimal Converter
Convert between binary-coded decimal (BCD/n-bit), hexadecimal, and decimal — common in ISO 8583 field encoding.
Character Encoding Converter
Convert data between ASCII, EBCDIC, and hex formats. Handles code page differences in mainframe-based payment systems.
Hex Dump Viewer
Create annotated, colour-coded hex dumps of binary payment files for manual analysis of message structures.
Webhook Inspector
Capture, inspect, and replay payment webhook payloads. Validates JSON, surfaces structure, and highlights key fields.
Webhook Signature Verifier
Verify Stripe, Adyen, Checkout.com, and Braintree webhook signatures with HMAC in your browser — confirm a payload was signed with your secret and never tampered with.
SD-JWT VC Decoder
Decode Selective Disclosure JWTs (SD-JWT VC) — the EUDI wallet credential format — splitting issuer JWT, disclosures, and Key Binding JWT, with digest matching against the _sd arrays.
OID4VP Request Decoder
Decode OpenID4VP authorization requests — DCQL credential queries, presentation definitions, and the transaction_data entries behind EUDI wallet payment SCA dynamic linking.
Tokenization Tester
Test PAN tokenization flows, validate token formats, and verify detokenization responses across vault providers.
Dispute Simulator
Simulate chargeback and dispute scenarios, generate evidence packages, and test dispute handling workflows end-to-end.
Payment Flow Builder
Visually construct and test multi-step payment flows with branching logic, conditional routing, and state management.
Need to test a whole payment system?
These tools are great for quick checks — the PayProbe Platform lets you build and run an entire payment network on your laptop.