Bencode Encoder — JSON to BitTorrent Bencode

Bencode (pronounced "bee-encode") is the data encoding defined by BEP 3 for the BitTorrent protocol. It supports exactly four types: integers as i<n>e (for example, i42e), byte strings as <length>:<data> (for example, 4:spam), lists as l...e (for example, l4:spami42ee), and dictionaries as d...e with keys sorted in byte order (for example, d3:bar4:spam3:fooi42ee). Torrent files (.torrent) are simply bencoded dictionaries.

Paste or type any JSON value — a string, integer, array, or object — into the input box and the bencoded output appears instantly, with no button to press. Switch tabs to inspect the same bytes as a hex dump or as an annotated tree that shows each value's bencode type and its encoded fragment. Use Copy for the raw text or Download to save the exact bytes as a .bencode file.

Bencode string lengths count UTF-8 bytes, not JavaScript characters. The rocket emoji \ud83d\ude80 looks like 2 characters to JavaScript (UTF-16 code units) but is 4 bytes in UTF-8 (F0 9F 9A 80), so it encodes as 4:<4 bytes>. Getting this right matters: torrent clients hash the exact bytes, so a length counted in characters would produce a corrupt file. This encoder always measures with TextEncoder, i.e. true UTF-8 byte length.

Dictionary keys are sorted lexicographically by their raw UTF-8 bytes — this is required by BEP 3 for a canonical encoding. For example, {"b": 1, "a": 2} encodes as d1:ai2e1:bi1ee, with "a" first regardless of the order you typed them. Canonical ordering is what makes a torrent's infohash deterministic: every client that bencodes the same info dictionary gets the identical SHA-1 hash.

No. Bencode has only four types — integers, byte strings, lists, and dictionaries — so there is no representation for 1.5, true, or null. This tool rejects such values instead of silently coercing them, and the error message shows the exact JSON path of the offending value (for example, $.settings.ratio) so you can fix it. If you need them, encode 1/0 for booleans or use a string.

JSON is a human-readable text format with objects, arrays, strings, numbers, booleans, and null. Bencode is a compact, deterministic, byte-oriented format with only integers, byte strings, lists, and dictionaries — no whitespace, no floats, no booleans, no null. Bencode was designed for BitTorrent metadata where exact bytes matter (hashing, signatures), while JSON is designed for readability and general data exchange.

A .torrent file is a bencoded dictionary containing keys like announce (the tracker URL) and info (a nested dictionary describing the files, piece length, and piece hashes). A BitTorrent client computes the torrent's infohash by taking the SHA-1 hash of the bencoded info dictionary — which is exactly why canonical key ordering and byte-accurate string lengths matter. Try the torrent-like example above to see a realistic structure encoded.

No. This bencode encoder runs entirely in your browser — the JSON you paste never leaves your device, there is no account or sign-up, and the page keeps working offline after it loads. That also means you can safely encode private torrent metadata or internal data structures without privacy concerns.