Open source at Back
Last updated 28 August 2026
Back uses the open-source software listed below. This page provides required licence notices and explains how to obtain source code for components with copyleft licences. To report a missing or incorrect attribution, contact legal@back.dev and we will correct it.
FFmpeg — and how to get its source
Backdrop processes video in your browser using a WebAssembly build of
FFmpeg, distributed as
@ffmpeg/core. That build is configured with --enable-gpl,
--enable-libx264 and --enable-libx265, so the whole artefact is
licensed under the GNU General Public License, version 2 or later.
We serve it to you at
https://backdrop.back.dev/core/ffmpeg-core.wasm and
/core/ffmpeg-core.js. The full licence text is at
/licenses/GPL-2.0.txt.
Written offer for source code. For at least three years from the date at
the top of this page, we will give any third party a complete machine-readable copy of the
corresponding source for the exact @ffmpeg/core build we distribute —
including the build scripts used to compile and install it — for no more than our cost
of physically performing the distribution. Ask at
legal@back.dev.
The upstream sources are also public: FFmpeg at git.ffmpeg.org/ffmpeg.git, x264 at code.videolan.org/videolan/x264, x265 at bitbucket.org/multicoreware/x265_git, and the WebAssembly build scripts at github.com/ffmpegwasm/ffmpeg.wasm.
Backdrop's own code is not derived from FFmpeg. It runs the FFmpeg build as a separate program in a dedicated worker, passing arguments in the same way as a shell.
Other third-party packages
The tables below list the third-party packages distributed with each product and their licences. MIT, BSD, ISC and Apache-2.0 require the copyright notice and licence text to accompany the software. Read the full licence text for every package, reproduced verbatim to meet those requirements. The longer licences are also available separately: Apache-2.0, MPL-2.0, GPL-2.0.
Backburner — 12 packages
| Package | Version | Licence | Copyright |
|---|---|---|---|
@dnd-kit/accessibility | 3.1.1 | MIT | Copyright (c) 2021, Claudéric Demers |
@dnd-kit/core | 6.3.1 | MIT | Copyright (c) 2021, Claudéric Demers |
@dnd-kit/sortable | 8.0.0 | MIT | Copyright (c) 2021, Claudéric Demers |
@dnd-kit/utilities | 3.2.2 | MIT | Copyright (c) 2021, Claudéric Demers |
@neondatabase/serverless | 1.1.0 | MIT | Copyright (c) 2022 - 2025 Neon Inc. |
drizzle-orm | 0.45.2 | Apache-2.0 | — |
js-tokens | 4.0.0 | MIT | Copyright (c) 2014, 2015, 2016, 2017, 2018 Simon Lydell |
loose-envify | 1.4.0 | MIT | Copyright (c) 2015 Andres Suarez <zertosh@gmail.com> |
react | 18.3.1 | MIT | Copyright (c) Facebook, Inc. and its affiliates. |
react-dom | 18.3.1 | MIT | Copyright (c) Facebook, Inc. and its affiliates. |
scheduler | 0.23.2 | MIT | Copyright (c) Facebook, Inc. and its affiliates. |
tslib | 2.8.1 | 0BSD | Copyright (c) Microsoft Corporation. |
Backpack — 15 packages
| Package | Version | Licence | Copyright |
|---|---|---|---|
@fastify/busboy | 2.1.1 | MIT | Copyright Brian White. All rights reserved. |
@neondatabase/serverless | 1.1.0 | MIT | Copyright (c) 2022 - 2025 Neon Inc. |
@vercel/blob | 1.1.1 | Apache-2.0 | copyright owner or entity authorized by |
async-retry | 1.3.3 | MIT | Copyright (c) 2021 Vercel, Inc. |
drizzle-orm | 0.45.2 | Apache-2.0 | — |
is-buffer | 2.0.5 | MIT | Copyright (c) Feross Aboukhadijeh |
is-node-process | 1.2.0 | MIT | — |
js-tokens | 4.0.0 | MIT | Copyright (c) 2014, 2015, 2016, 2017, 2018 Simon Lydell |
loose-envify | 1.4.0 | MIT | Copyright (c) 2015 Andres Suarez <zertosh@gmail.com> |
react | 18.3.1 | MIT | Copyright (c) Facebook, Inc. and its affiliates. |
react-dom | 18.3.1 | MIT | Copyright (c) Facebook, Inc. and its affiliates. |
retry | 0.13.1 | MIT | Copyright (c) 2011: |
scheduler | 0.23.2 | MIT | Copyright (c) Facebook, Inc. and its affiliates. |
throttleit | 2.1.0 | MIT | Copyright (c) TJ Holowaychuk <tj@tjholowaychuk.com> |
undici | 5.29.0 | MIT | Copyright (c) Matteo Collina and Undici contributors |
Backdrop — 63 packages
| Package | Version | Licence | Copyright |
|---|---|---|---|
@ffmpeg/core | 0.12.10 | GPL-2.0-or-later | — |
@ffmpeg/ffmpeg | 0.12.15 | MIT | — |
@ffmpeg/types | 0.12.4 | MIT | — |
@ffmpeg/util | 0.12.2 | MIT | — |
@hocuspocus/common | 4.4.0 | MIT | Copyright (c) 2023, Tiptap GmbH |
@hocuspocus/provider | 4.4.0 | MIT | Copyright (c) 2023, Tiptap GmbH |
@hocuspocus/server | 4.4.0 | MIT | Copyright (c) 2023, Tiptap GmbH |
@lifeomic/attempt | 3.1.0 | MIT | Copyright 2018 LifeOmic |
@types/dom-mediacapture-transform | 0.1.12 | MIT | Copyright (c) Microsoft Corporation. |
@types/dom-webcodecs | 0.1.13 | MIT | Copyright (c) Microsoft Corporation. |
@vercel/blob | 2.6.1 | Apache-2.0 | copyright owner or entity authorized by |
@vercel/cli-config | 0.2.1 | Apache-2.0 | copyright owner or entity authorized by |
@vercel/cli-exec | 1.0.0 | Apache-2.0 | copyright owner or entity authorized by |
@vercel/oidc | 3.8.1 | Apache-2.0 | copyright owner or entity authorized by |
async-mutex | 0.5.0 | MIT | Copyright (c) 2016 Christian Speckner <cnspeckn@googlemail.com> |
async-retry | 1.3.3 | MIT | Copyright (c) 2021 Vercel, Inc. |
cross-spawn | 7.0.6 | MIT | Copyright (c) 2018 Made With MOXY Lda <hello@moxy.studio> |
crossws | 0.4.10 | MIT | Copyright (c) Pooya Parsa <pooya@pi0.io> |
execa | 5.1.1 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com) |
fractional-indexing | 4.0.0 | CC0-1.0 | Copyright and Related Rights (defined below) upon the creator |
get-stream | 6.0.1 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com) |
human-signals | 2.1.0 | Apache-2.0 | copyright owner or entity authorized by |
is-buffer | 2.0.5 | MIT | Copyright (c) Feross Aboukhadijeh |
is-node-process | 1.2.0 | MIT | — |
is-stream | 2.0.1 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com) |
isexe | 2.0.0 | ISC | Copyright (c) Isaac Z. Schlueter and Contributors |
isomorphic.js | 0.2.5 | MIT | Copyright (c) 2020 Kevin Jahns <kevin.jahns@protonmail.com>. |
jose | 5.10.0 | MIT | Copyright (c) 2018 Filip Skokan |
kleur | 4.1.5 | MIT | Copyright (c) Luke Edwards <luke.edwards05@gmail.com> (lukeed.com) |
lib0 | 0.2.117 | MIT | Copyright (c) 2019 Kevin Jahns <kevin.jahns@protonmail.com>. |
mediabunny | 1.51.0 | MPL-2.0 | copyright doctrines of fair use, fair dealing, or other |
merge-stream | 2.0.0 | MIT | Copyright (c) Stephen Sugden <me@stephensugden.com> (stephensugden.com) |
mimic-fn | 2.1.0 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com) |
npm-run-path | 4.0.1 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com) |
onetime | 5.1.2 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com) |
os-paths | 4.4.0 | MIT | Copyright (c) Roy Ivy III <rivy.dev@gmail.com> |
path-key | 3.1.1 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com) |
pg | 8.22.0 | MIT | Copyright (c) 2010 - 2021 Brian Carlson |
pg-connection-string | 2.14.0 | MIT | Copyright (c) 2014 Iced Development |
pg-int8 | 1.0.1 | ISC | Copyright © 2017, Charmander <~@charmander.me> |
pg-pool | 3.14.0 | MIT | Copyright (c) 2017 Brian M. Carlson |
pg-protocol | 1.15.0 | MIT | Copyright (c) 2010 - 2021 Brian Carlson |
pg-types | 2.2.0 | MIT | — |
pgpass | 1.0.5 | MIT | — |
postgres-array | 2.0.0 | MIT | Copyright (c) Ben Drucker <bvdrucker@gmail.com> (bendrucker.me) |
postgres-bytea | 1.0.1 | MIT | Copyright (c) Ben Drucker <bvdrucker@gmail.com> (bendrucker.me) |
postgres-date | 1.0.7 | MIT | Copyright (c) Ben Drucker <bvdrucker@gmail.com> (bendrucker.me) |
postgres-interval | 1.2.0 | MIT | Copyright (c) Ben Drucker <bvdrucker@gmail.com> (bendrucker.me) |
retry | 0.13.1 | MIT | Copyright (c) 2011: |
shebang-command | 2.0.0 | MIT | Copyright (c) Kevin Mårtensson <kevinmartensson@gmail.com> (github.com/kevva) |
shebang-regex | 3.0.0 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com) |
signal-exit | 3.0.7 | ISC | Copyright (c) 2015, Contributors |
split2 | 4.2.0 | ISC | Copyright (c) 2014-2018, Matteo Collina <hello@matteocollina.com> |
strip-final-newline | 2.0.0 | MIT | Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com) |
throttleit | 2.1.0 | MIT | Copyright (c) TJ Holowaychuk <tj@tjholowaychuk.com> |
tslib | 2.8.1 | 0BSD | Copyright (c) Microsoft Corporation. |
undici | 6.28.0 | MIT | Copyright (c) Matteo Collina and Undici contributors |
which | 2.0.2 | ISC | Copyright (c) Isaac Z. Schlueter and Contributors |
xdg-app-paths | 5.5.1 | MIT | Copyright (c) Roy Ivy III <rivy.dev@gmail.com> |
xdg-portable | 7.3.0 | MIT | Copyright (c) Roy Ivy III <rivy.dev@gmail.com> |
xtend | 4.0.2 | MIT | Copyright (c) 2012-2014 Raynos. |
yjs | 13.6.31 | MIT | Copyright (c) 2023 |
zod | 4.1.11 | MIT | Copyright (c) 2025 Colin McDonnell |
Fonts and other assets
Backdrop's caption renderer embeds DejaVu Sans, which is free to use and redistribute under the DejaVu licence and the underlying Bitstream Vera Fonts Copyright. Bitstream Vera is Copyright © 2003 Bitstream, Inc. DejaVu changes are Copyright © the DejaVu contributors. Full text at /licenses/third-party.txt.
Back's source code
Backburner, Backpack, Backdrop and this site are not currently open source.