Payment Testing Tools
Every tool you need,
ready to use now
102 free, browser-based payment tools — 88 stable, 14 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 IBANs against the SWIFT IBAN Registry (89 countries): length, BBAN structure and MOD 97-10 check digits; extracts country, check digits and BBAN.
Amount Formatter
Format and convert payment amounts using ISO 4217 minor units for all 165 active currency codes, with exact decimal maths and ISO 8583 DE 4 (n12) output.
Luhn Algorithm
Standalone Luhn check for any numeric string. Step-by-step calculation trace, digit-level breakdown.
Test Card Generator
Published test card numbers — a selection from Stripe’s official list plus Braintree and PayPal Payflow sandbox PANs — for Visa, Mastercard, Amex, Discover, JCB, Diners and UnionPay: approvals, declines, CVC/ZIP check failures and 3D Secure, with the CVC, expiry and ZIP to use.
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 synthetic test card data — Luhn-valid PAN, expiry, CVV, ISO/IEC 7813 Track 1 & 2 and EMV tags 5A, 5F24, 57 — 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 BER-TLV hex from tag/value pairs: multi-byte tags, 81/82/83 lengths, nested templates by pasting built TLV as a template’s value, with format and length warnings from the EMV Tag Reference.
EMV Tag Reference
Search 125 EMV tags — most EMV 4.4 Book 3 Annex A1 data elements plus common contactless-kernel and scheme tags — by tag ID or keyword: format, length, source and, where it differs, per-kernel meaning.
PDOL / CDOL Builder
Parse a PDOL or CDOL, fill in terminal values and build the DOL-related data per EMV Book 3 §5.4, with the GET PROCESSING OPTIONS or GENERATE AC command that carries it.
TVR Decoder
Decode the Terminal Verification Results (tag 95) 5-byte bitfield — every EMV 4.4 flag — into human-readable descriptions.
AIP Decoder
Decode the Application Interchange Profile (tag 82): offline authentication (SDA/DDA/CDA/XDA), CVM and risk-management support, plus the Kernel 2 contactless bits.
IAD Decoder
Decode Issuer Application Data (tag 9F10) for Visa (IAD formats 0–4), Mastercard M/Chip 4 / Advance and EMV CCD cards — DKI, CVN and a bit-level CVR breakdown.
CVM List Decoder
Parse and explain the Cardholder Verification Method list (tag 8E) — Amount X/Y and the priority rules for PIN, signature, biometrics 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 reader in Visa Kernel 3 and UnionPay Kernel 7.
Amex Reader Capabilities Decoder
Decode Amex ExpressPay Enhanced Contactless Reader Capabilities (tag 9F6E) — the Kernel 4 reader bitmap and kernel version, 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 (including indefinite length) from hex, base64 or PEM — 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.
EMV QR Decoder / Builder
Parse and build EMVCo Merchant-Presented Mode (MPM) QR payloads: ID-length-value fields and templates, CRC-16/CCITT-FALSE check, core MPM v1.1 field rules, scheme detection by GUID (PromptPay, PIX, PayNow, DuitNow, QRIS, VietQR, Bharat QR…) and validated generation for PromptPay, PIX, Visa and Mastercard.
ARQC / ARPC Calculator
Compute and verify EMV ARQC and ARPC cryptograms for Visa CVN 10 and CVN 18: session key derivation, ISO 9797-1 MAC and ARPC methods 1 and 2.
CVV / CVC Calculator
Calculate CVV/CVC, CVV2/CVC2 and iCVV from PAN, expiry, service code and a double-length CVK — the shared Visa and Mastercard method. Dynamic CVV (dCVV) is not computed.
CAVV Calculator
Inspect 3-D Secure CAVV / AAV values: base64 ↔ hex, type by length and leading byte (Visa 20-byte CAVV, Mastercard 21-byte SPA2 AAV) and the ECI values that go with them. Field layouts and scheme algorithms are not public, so no fields are decoded and no CAVV/AAV is generated (the MAC tab is an illustrative TDES CBC-MAC).
CAP Calculator
Turn a card’s GENERATE AC response into a CAP / DPA one-time code with the Issuer Proprietary Bitmap — the reader-side EMV-CAP 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 ISO/IEC 9797-1 MACs with DES or TDEA: Algorithm 1 (CBC-MAC) and Algorithm 3 (Retail MAC, ANSI X9.19), with padding methods 1 and 2.
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 DES, TDES and AES keys: DES/TDES zero-block encryption, the X9.24-1:2017 AES-CMAC KCV and the legacy AES-ECB KCV. Essential for key loading ceremonies and HSM validation.
Key Block Decoder
Parse and inspect TR-31 / X9.143 key blocks — version, key usage, algorithm, mode of use, exportability, optional blocks and MAC.
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.
PCI KMO Standard
PCI Key Management and Operations (KMO) v1.0 — the key lifecycle it governs, the assess-once assessment process, and how it relates to PCI PIN, P2PE, and PTS HSM.
HSM Key Composer
XOR 2–9 TDES or AES key components, check each component’s KCV and DES odd parity, and get the combined key and its KCV (TDES encrypt-zeros; AES-CMAC per X9.24-1:2017, plus legacy ECB).
Keyshare Generator
Generate random TDES or AES test key components, or split an existing key into 2–9 XOR components, with the KCV of each component and of the combined key.
UDK Calculator
Derive Unique Derived Keys (UDK) from an Issuer Master Key and PAN/PAN Sequence Number for EMV personalization.
DUKPT Key Derivation
Derive IPEK and per-transaction session keys from a Base Derivation Key (BDK) and Key Serial Number (KSN) per ANSI X9.24-1 Triple-DES DUKPT — PIN, MAC, and data-encryption variants.
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 Visa PIN Verification Values (PVV) from PAN, PIN, PVK index and a double-length PVK, for test cards.
PIN Verification (IBM 3624)
Calculate IBM 3624 natural PINs and PIN offsets (4 to 12 digits) with DES or TDES keys and configurable validation data, pad character and decimalisation table.
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 ASCII ISO 8583:1987 messages, as text or a hex dump: the MTI, primary, secondary and tertiary bitmaps, and every data element with its ISO format.
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 8583:1987 data elements — format, length and description, with a detail page per DE; usage notes, subfield layouts and examples for the common fields, Visa / Mastercard dialect notes where they diverge, and the main ISO 8583:1993 reassignments.
SWIFT MT Validator
Parse and validate SWIFT FIN (MT) messages — header blocks, UETR, field formats and character set, BIC and IBAN, currency decimals and MT 103 network rules — with field-level errors.
IPM & CTF Decoder
Decode Mastercard IPM clearing records and files (RDW/VBS, 1014 blocking, EBCDIC or ASCII, MTI, bitmaps, data elements and PDS) and Visa Base II 168-byte TCRs (TCR 0 in full and the leading TCR 5 fields for draft, chargeback and reversal TCs; single-source layout).
ISO 20022 Message Reference
CBPR+ / HVPS+ ISO 20022 payment messages — pacs, pain, camt — with MT equivalents, key elements, and the current structured-address / native-MX migration status per rail (Swift, Fedwire, SEPA, CHIPS).
ISO 20022 Reason Codes
Reject, return and recall reason codes for pacs.002, pacs.004, camt.056 and camt.029 — AC01, AC04, AM04, MS03, FOCR and more — with the ISO definition, what to do and SEPA usage, one page per code.
ISO 20022 Validator
Validate pain.001, pacs.008, pacs.002, pacs.004 returns, camt.053 and camt.054: mandatory elements, data types, IBAN/BIC, totals, return reasons and statement balances, plus CBPR+ and SEPA rules.
Response Code Reference
Searchable ISO 8583 DE 39 response codes with Visa and Mastercard meanings — Visa decline categories and reattempt limits, plus Mastercard Merchant Advice Codes.
Julian Date Converter
Convert between calendar dates and payment Julian (ordinal) dates — YDDD as in ARNs and RRNs, YYDDD and YYYYDDD — with leap-year checks and the ISO week date.
3DS2 Message Builder & Decoder
Sketch EMV 3DS (3DS2) AReqs and decode AReq, ARes, CReq/CRes (incl. base64url creq/cres), RReq and Erro messages — transStatus, ECI, reason and error codes explained field by field.
BIN Lookup
Identify the card scheme, card lengths and Luhn rule from the first 6–8 digits (BIN/IIN), with issuer, card type and country from binlist.net when it has them.
MCC Lookup
Look up ISO 18245 Merchant Category Codes with the ISO description, the Visa and Mastercard titles, and which lists carry each code.
Currency & Country Codes
Browse every ISO 4217 currency and fund code with numeric codes and minor units, and all ISO 3166-1 country codes with their currencies.
RID & AID Catalog
Searchable catalog of ISO/IEC 7816-5 RIDs and EMV AIDs by code, scheme, provider or country — built from the EFTlab lists, with payment RIDs and AIDs cross-checked against the ISO RID registration list and open-source EMV libraries.
APDU Response Codes
Look up ISO/IEC 7816-4 APDU status words (SW1 SW2) like 9000, 6A82, 6985 — category, description and where each value is defined (ISO, SIM/UICC, DESFire, MULTOS or card-OS specific), 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, with Visa and Mastercard values.
Chargeback Reason Codes
Visa, Mastercard and Amex chargeback reason codes — Visa Claims Resolution conditions, Mastercard’s current chargeback types with legacy codes, and Amex codes — with time limits, pre-arb deadlines and key 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
Reference of 60 cryptographic terms in payment networks — key hierarchy, EMV cryptograms and data objects, contactless, DUKPT, key transport and HSM infrastructure — with a big-picture network map.
Blockchain & Payments Glossary
84-term reference for blockchain in payments — consensus, cryptography, stablecoins and their regulation (MiCA, GENIUS Act, Hong Kong), CBDCs, Lightning, cross-border rails and standards — with an ecosystem map and payment use cases.
Wallet Address Validator
Validate Bitcoin (P2PKH, P2SH, Bech32, Taproot Bech32m), Ethereum (EIP-55), Litecoin, Dogecoin, Tron, Solana, XRP (incl. X-address), Stellar (incl. muxed) and Cardano (Shelley) addresses — checksum, format, and network detection.
Blockchain Tx Decoder
Decode raw Bitcoin and Ethereum transactions — Bitcoin inputs, outputs, scripts, witnesses, TXID/wTXID and weight; Ethereum legacy and EIP-2930/1559/4844/7702 transactions with tx hash, recovered sender and ABI-decoded calldata for known selectors.
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 and EIP-712 typed data: function calls, type hash, domain separator and signing digest, with USDC, EURC, PYUSD, USDT and other stablecoins named and amounts shown in real units.
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.
ISO 8583 ↔ On-Chain Settlement Mapper
Map card settlement fields (DE 4, 5, 9, 15, 32, 49, 50, 97, recon totals) to their on-chain stablecoin equivalents, see what exists on one side only, and convert a settlement amount into both forms.
Stablecoin Settlement Simulator
Step through card settlement in fiat and in stablecoins and a stablecoin cross-border payout, and compare when acquirers get funds for each weekday — weekends and holidays included.
Stablecoin Payment Flows
Every stablecoin payment flow step by step — deposit address, payment request, EIP-3009 signed authorization and authorize-and-capture checkout, stablecoin cards, ramps, mint/redeem, B2B Travel Rule, CCTP, refunds and subscriptions — with best practices and a payment matcher for short, late and wrong-chain transfers.
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 / MPP Header Decoder
Decode and build HTTP 402 payment headers — x402 PAYMENT-REQUIRED / PAYMENT-SIGNATURE / PAYMENT-RESPONSE (v2 and v1) and MPP WWW-Authenticate: Payment challenges and Authorization: Payment credentials. Base64 → annotated fields with network, asset and amount resolution.
BVNK Flow Simulator
Step through the Mastercard-owned BVNK stablecoin platform flows — Payment Link pay-ins with locked quotes, reusable Channel top-ups at spot rate, and two-step payouts from a fiat wallet — with every API call, status, and webhook annotated.
AP2 Mandate Decoder
Decode Agent Payments Protocol (AP2 v0.2) Checkout and Payment Mandates — open and closed SD-JWT VCs — and receipts: resolves disclosures, checks the chain binding, checkout hash and agent signature, and evaluates constraints.
AP2 Flow Simulator
Step through an Agent Payments Protocol (AP2 v0.2) purchase — human present (closed Checkout and Payment Mandates signed by the user) and human not present (open mandates with constraints, closed ones signed by the agent) — through verification and signed receipts.
HTTP Signature / Trusted Agent Decoder
Decode RFC 9421 HTTP Message Signatures — the Signature-Input and Signature headers behind Web Bot Auth, Visa Trusted Agent Protocol and Mastercard Agent Pay. Rebuilds the signature base, checks freshness and Content-Digest, verifies with a pasted key.
HEX ↔ ASCII Converter
Convert hex to text and text to hex in ASCII, UTF-8 or Latin-1, with a byte inspector showing each byte’s offset, decimal, binary and character class — for payment message debugging.
Base64 Encoder / Decoder
Encode and decode Base64 and Base64URL (RFC 4648) — text or hex bytes, padding and MIME/PEM line breaks. Useful for API payloads, certificate data and token inspection.
BCD / Hex / Decimal Converter
Convert decimal and hexadecimal to and from packed BCD — EMV n and cn, signed COMP-3 — plus unpacked BCD, exactly for any length, as used in ISO 8583 and EMV fields.
Character Encoding Converter
Convert text and hex between ASCII/Latin-1 and EBCDIC code page 037, and compare a byte’s ASCII and EBCDIC readings side by side.
Hex Dump Viewer
View raw bytes as an xxd-style hex dump — offset, grouped hex and ASCII columns, 8 or 16 bytes per row — and copy the same text xxd -c 8|16 -g 2|4 prints.
Webhook Inspector
Paste and inspect payment webhook payloads: validates JSON (RFC 8259), pretty-prints or minifies without altering values, flags duplicate keys and numbers JavaScript would not read back as written, and lists fields by path.
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 RFC 9901 SD-JWTs and SD-JWT VCs — an EUDI wallet credential format: issuer JWT, disclosures and Key Binding JWT, with digest matching (nested and array disclosures, _sd_alg), the KB-JWT sd_hash check and the processed payload.
OID4VP Request Decoder
Decode OpenID4VP 1.0 authorization requests — URLs, signed request objects and Digital Credentials API requests: client identifier prefixes, DCQL queries and the transaction_data entries (with their expected KB-JWT hashes) behind EUDI wallet payment SCA; flags pre-1.0 draft parameters such as presentation_definition.
Token Format Checker
See what a token's format does and does not reveal: Luhn, network, valid length, masking limits — card or network token, custom token, or opaque vault ID.
Wallet Provisioning Inspector
Identify and check push-provisioning payloads for Apple Pay and Google Wallet: PKAddPaymentPassRequest, Mastercard IIDD / Opaque Payment Card, push account receipts, Visa JWE fields, Google UAPP (OpenPGP) and app-to-app ID&V.
Custom Token Generator
Make proprietary payment tokens without the card networks: vault tokens, vaultless FF1 format-preserving encryption or keyed hashes. Keep the BIN and last four, force a Luhn failure, and detokenize.
Dispute Simulator
Simulate chargeback and dispute scenarios, generate evidence packages, and test dispute handling workflows end-to-end.
Verification of Payee Simulator
Play the Responding PSP in the EPC Verification Of Payee scheme: payee name + IBAN versus the name on file → MTCH / CMTC / NMTC / NOAP, with every normalisation and similarity step explained.
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.