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Tool, language and decoders for working with binary data.

fq demo

Basic usage is fq . file or fq d file.

For details see


fq is inspired by the well known jq tool and language and allows you to work with binary formats the same way you would using jq. In addition it can present data like a hex viewer, transform, slice and concatenate binary data. It also supports nested formats and has an interactive REPL with auto-completion.

It was originally designed to query, inspect and debug media codecs and containers like mp4, flac, mp3, jpeg. But has since then been extended to support a variety of formats like executables, packet captures (with TCP reassembly) and serialization formats like JSON, YAML, XML, ASN1 BER, Avro, CBOR, protobuf. In addition it also has functions to work with URL:s, convert to/from hex, number bases, search for things etc.

In summary it aims to be jq, hexdump, dd and gdb for files combined into one.

NOTE: fq is still early in development so things might change, be broken or do not make sense. That also means that there is a great opportunity to help out!


  • Make binaries accessible, queryable and sliceable.
  • Nested formats and bit-oriented decoding.
  • Quick and comfortable CLI tool.
  • Bits and bytes transformations.


  • Make it useful enough that people want to help improve it.
  • Inspire people to create similar tools.

Supported formats

aac_frame, adts, adts_frame, aiff, amf0, apev2, apple_bookmark, ar, asn1_ber, av1_ccr, av1_frame, av1_obu, avc_annexb, avc_au, avc_dcr, avc_nalu, avc_pps, avc_sei, avc_sps, avi, avro_ocf, bencode, bitcoin_blkdat, bitcoin_block, bitcoin_script, bitcoin_transaction, bits, bplist, bsd_loopback_frame, bson, bytes, bzip2, cbor, csv, dns, dns_tcp, elf, ether8023_frame, exif, fairplay_spc, flac, flac_frame, flac_metadatablock, flac_metadatablocks, flac_picture, flac_streaminfo, gif, gzip, hevc_annexb, hevc_au, hevc_dcr, hevc_nalu, hevc_pps, hevc_sps, hevc_vps, html, icc_profile, icmp, icmpv6, id3v1, id3v11, id3v2, ipv4_packet, ipv6_packet, jpeg, json, jsonl, macho, macho_fat, markdown, matroska, mp3, mp3_frame, mp3_frame_vbri, mp3_frame_xing, mp4, mpeg_asc, mpeg_es, mpeg_pes, mpeg_pes_packet, mpeg_spu, mpeg_ts, msgpack, ogg, ogg_page, opus_packet, pcap, pcapng, pg_btree, pg_control, pg_heap, png, prores_frame, protobuf, protobuf_widevine, pssh_playready, rtmp, sll2_packet, sll_packet, tar, tcp_segment, tiff, tls, toml, tzif, udp_datagram, vorbis_comment, vorbis_packet, vp8_frame, vp9_cfm, vp9_frame, vpx_ccr, wasm, wav, webp, xml, yaml, zip

It can also work with some common text formats like URL:s, hex, base64, PEM etc and for some serialization formats like XML, YAML etc it can transform both from and to jq values.

For details see and



Use one of the methods listed below or download a pre-built release for macOS, Linux or Windows. Unarchive it and move the executable to PATH etc.

On macOS if you don't install using one of the method below you might have to manually allow the binary to run. This can be done by trying to run the binary, ignore the warning and then go into security preference and allow it. Same can be done with this command:

xattr -d fq && spctl --add fq

Homebrew (macOS)

brew install wader/tap/fq


On macOS, fq can also be installed via MacPorts. More details here.

sudo port install fq


fq can be installed via scoop.

scoop install fq

Arch Linux

fq can be installed from the community repository using pacman:

pacman -S fq

You can also build and install the development (VCS) package using an AUR helper:

paru -S fq-git


nix-shell -p fq


Use the fq port.


Currently in edge testing but should work fine in stable also.

apk add -X fq

Build from source

Make sure you have go 1.18 or later installed.

To install directly from git repository (no clone needed) do:

# build and install latest release
go install

# build and install latest master
go install

# copy binary to $PATH if needed
cp "$(go env GOPATH)/bin/fq" /usr/local/bin

To build, run and test from source:

# build and run
go run .
# build and run with arguments
go run . -d mp3 . file.mp3
# just build
go build -o fq .
# run all tests and build binary
make test fq

TODO and ideas


Development and adding a new decoder


Thanks and related projects

This project would not have been possible without itchyny's jq implementation gojq. I also want to thank HexFiend for inspiration and ideas and stedolan for inventing the jq language.

Similar or related works


  • HexFiend Hex editor for macOS with format template support.
  • binspector Binary format analysis tool with query language and REPL.
  • kaitai Declarative binary format parsing.
  • Wireshark Decodes network traffic (tip: tshark -T json).
  • MediaInfo Analyze media files (tip mediainfo --Output=JSON and mediainfo --Details=1).
  • GNU poke The extensible editor for structured binary data.
  • ffmpeg/ffprobe Powerful media libraries and tools.
  • hexdump Hex viewer tool.
  • hex Interactive hex viewer with format support via lua.
  • hachoir General python library for working binary data.
  • scapy Decode/Encode formats, focus on network protocols.

Projects and Standards


fq is distributed under the terms of the MIT License.

See the LICENSE file for license details.

Licenses of direct dependencies: