TLV Parser

Parses raw BER-TLV or EMV hex data into a structured tree, showing each tag's ID, resolved name where known, byte length, and decoded value, recursively expanding any constructed (nested) tags into their child elements.

Paste a hex string of BER-TLV or EMV data into the input box; the parsed tag tree appears automatically below it, with constructed tags shown as expandable groups containing their nested tags.

Parsing `5A08 4111111111111111` produces a single primitive tag: ID `5A`, resolved name "PAN" (Primary Account Number), length `08` (8 bytes), and value `4111111111111111` — exactly the structure a chip card or payment terminal would read from that byte sequence.

Every BER-TLV element has three parts: the tag byte(s) identify what kind of data follows, the length byte(s) state exactly how many bytes of value come next, and the value itself is either raw data (a primitive tag) or more nested TLV elements (a constructed tag, identified by a specific bit in the tag byte).

Common EMV tags — such as `5A` (PAN), `5F20` (Cardholder Name), `9F26` (Application Cryptogram), `57` (Track 2 Equivalent Data), and `4F`/`84` (Application Identifier) — are resolved to their human-readable names automatically; tags outside this dictionary are still parsed structurally and shown by their raw hex ID.

BER-TLV is the encoding inside EMV chip card data (the format read by payment terminals), many ISO 8583 message fields, and various smart card and government ID applications, wherever structured, self-describing binary data needs to be nested arbitrarily deep.

Parsing happens entirely in your browser via client-side JavaScript; the hex data you paste is never uploaded to a server, which matters when working with real card or terminal data.