Bencode Decoder — BitTorrent Bencode to JSON

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). A .torrent file is simply a bencoded dictionary.

Paste or type the bencoded text into the input box and the decoded JSON appears instantly — there is no button to press. Switch tabs to inspect the result as pretty JSON, as an annotated tree showing each value's bencode type, or as decode statistics. Choose how byte strings render (UTF-8 text, hex, or base64) and how integers render (auto, number, or string) with the options above the output. Use Copy for the JSON or Download to save it as a .json file.

Bencode is a byte-oriented format, so errors are reported as exact byte offsets — for example, "unexpected byte at offset 7" — counting from 0 at the start of your input. The error box also shows a context snippet with a caret pointing at the offending byte. The most common causes are a truncated paste, a wrong string length (4:spa declares 4 bytes but only 3 follow the colon), or stray characters after a complete value.

Torrent piece hashes are raw binary bytes, not text, so they are not valid UTF-8. This decoder renders a byte string as UTF-8 text only when the bytes are valid UTF-8; otherwise it falls back to lowercase hex (or base64, if you pick that option). Use the byte-string options above the output to switch between Auto, UTF-8 text, Hex, and Base64 at any time — decoding is live.

BEP 3 requires dictionary keys to be sorted lexicographically by raw bytes — that ordering is what makes encodings canonical and torrent infohashes deterministic. This decoder still decodes the value, but warns you that the input is non-canonical. Note that duplicate keys are rejected outright, and so is any trailing data after a complete value. Strict encoders always emit sorted keys, so you will never see this warning on output from our Bencode Encoder.

It means a complete bencode value ended, but extra bytes followed — for example, i42eXYZ. A strict decoder accepts exactly one top-level value, and leftover bytes almost always indicate a truncated copy-paste or two values pasted together. Remove the extra bytes, or decode each value separately.

Yes — click "Load .torrent file" and pick the file. It is read as raw bytes directly in your browser (binary-safe), so the 20-byte SHA-1 piece hashes decode correctly and show as hex. Your file never leaves your device: there is no upload, no account, and no server involved.

Bencode integers have arbitrary precision, but JavaScript numbers are exact only up to 2^53 − 1 (9007199254740991). In Auto mode, integers that fit become JSON numbers and larger ones become JSON strings, so no digit is ever lost — try decoding i1208925819614629174706176e. Choose "Always number" to force numbers (large values may round) or "Always string" to keep every integer as text.

They are one-way complements: this page only decodes bencode into JSON, while our Bencode Encoder (/tools/bencode-encoder/) only encodes JSON into bencode. Keeping them separate makes each tool's intent unambiguous — there is deliberately no encode mode on this page. If you need to go the other direction, use the encoder.

No. This bencode decoder runs entirely in your browser — the text or .torrent file you decode 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 inspect private torrent metadata without privacy concerns.