sndr 0.3.0

Easily and securely share files from the command line. A fully featured Send client (formerly ffsend, rebranded by tarnover).
sndr-0.3.0 is not a library.

sndr

Latest release License

A command-line client for the Send end-to-end-encrypted file-sharing protocol. Upload a file, hand someone a one-shot link, walk away. The server stores ciphertext, the recipient holds the only key, the share expires on its own.

$ sndr upload paper.pdf
https://snd.dx.pe/dl/8a3f.../#xY7q...

That URL is everything: file ID in the path, decryption key after the #. Anyone who gets it can fetch and decrypt — and only them, because the server never sees the key.

Why use this

  • Send a file once, securely — the alternative is "DM you a Google Drive link" (the operator holds your file forever) or "SFTP you onto my box" (you need an account and a network path). sndr is one command, no signup, no persistent footprint.
  • Encrypted before it leaves your machine — AES-128-GCM with a random 128-bit key. The server stores opaque ciphertext.
  • One-shot by default — 1 download, 24-hour expiry. Configurable up to 20 downloads / 7 days on most instances.
  • Optional password on top of the URL secret, for cases where the link itself might leak.
  • Server-shipped JavaScript is out of the loop — sndr ships its own implementation of the protocol, so a compromised server cannot swap out the crypto layer the way it could for a browser client. This is the real reason to use a CLI over the web UI for sensitive transfers.

It's not the right tool for everything. If you need persistent hosting, multi-recipient access control, or files larger than a few hundred MB on a public instance, use something else.

Install

sndr is a young fork and is not yet packaged on crates.io or any distro. Install from source:

cargo install --git https://github.com/tarnover/sndr.git --locked
sndr --help

Requires Rust 1.63 or newer. On Linux, you also want ca-certificates (usually already installed), and xclip or xsel if you want --copy to work. No system OpenSSL needed — the default crypto backend is pure Rust.

For a hands-on build (cloning, debug build, testing locally), see Build below.

Usage

Upload

# The simple case
sndr upload paper.pdf

# 5 downloads, 1 hour expiry, password-protect, copy URL to clipboard
sndr upload --downloads 5 --expiry-time 1h --password --copy paper.pdf

# Upload a directory (auto-tars it)
sndr upload --archive ~/photos

# Read from stdin
tar c some/dir | sndr upload --name backup.tar -

# Different host
sndr upload --host https://send.example.com/ paper.pdf

Receive

# Download to current directory, picking the original filename
sndr download "https://snd.dx.pe/dl/8a3f.../#xY7q..."

# Download to a specific path
sndr download -o /tmp/paper.pdf "https://snd.dx.pe/dl/8a3f.../#xY7q..."

# Inspect without downloading (does not consume a download slot)
sndr info "https://snd.dx.pe/dl/8a3f.../#xY7q..."
sndr exists "https://snd.dx.pe/dl/8a3f.../#xY7q..."

Manage your shares

sndr keeps a local index of shares you've uploaded, so you can list, re-share, or revoke them without re-pasting URLs.

sndr history                        # list your active shares
sndr password <url>                 # add or change the share password
sndr parameters <url> --downloads 2 # change the download cap
sndr delete <url>                   # revoke a share server-side
sndr history forget <url>           # drop a share from local history only

The history file lives at ~/.cache/sndr/history.toml and contains owner tokens, so it's stored with 0600 perms. Use --incognito (or SNDR_INCOGNITO=1) to skip recording anything locally.

Configuration

Every flag has an environment variable equivalent. Set what you use most often in your shell rc.

Variable Flag Default
SNDR_HOST --host <URL> https://snd.dx.pe/
SNDR_HISTORY --history <FILE> ~/.cache/sndr/history.toml
SNDR_EXPIRY_TIME --expiry-time <SECONDS> 24 h
SNDR_DOWNLOAD_LIMIT --download-limit <N> 1
SNDR_TIMEOUT --timeout <SECONDS> 30 s
SNDR_TRANSFER_TIMEOUT --transfer-timeout <SECONDS> 24 h
SNDR_BASIC_AUTH --basic-auth <USER:PASSWORD> none
SNDR_API --api <VERSION> autodetect

Flag-style env vars (presence enables; the value is ignored):

SNDR_FORCE         SNDR_NO_INTERACT   SNDR_YES         SNDR_INCOGNITO
SNDR_OPEN          SNDR_ARCHIVE       SNDR_EXTRACT     SNDR_COPY
SNDR_COPY_CMD      SNDR_QUIET         SNDR_VERBOSE

There is no configuration file. Set env vars, or pass flags.

Per-subcommand binaries

If you compile with the default infer-command feature, you can symlink the binary under one of three special names and it dispatches to the matching subcommand:

ln -s "$(which sndr)" /usr/local/bin/sndrput   # → sndr upload
ln -s "$(which sndr)" /usr/local/bin/sndrget   # → sndr download
ln -s "$(which sndr)" /usr/local/bin/sndrdel   # → sndr delete

sndrput file.pdf      # equivalent to: sndr upload file.pdf

Security

What the server sees

  • Ciphertext bytes of your file.
  • A few plaintext fields needed to route the share: file ID, nonce, owner-token hash, expiry timestamp, download counter, encrypted size.
  • The IP address of every uploader and downloader.

What the server cannot see

  • The file's contents, filename, or MIME type. All three are encrypted client-side before upload.
  • The URL fragment (#...), which is the decryption key. HTTP does not include the fragment in requests, and sndr is careful to preserve it across redirects.

Threat model in one paragraph

sndr is safe to use over a hostile network: TLS protects the ciphertext in flight, and the operator never holds the key. It is also safe against a curious operator: they can see ciphertext but not decrypt it. It is not safe against a compromised operator who can swap the web client's JavaScript: when you open a share link in a browser, the server's JS reads the fragment and could exfiltrate it. sndr itself never runs server-supplied code, which is the whole reason to prefer the CLI for sensitive shares.

The decryption key is in the URL. Treat the URL like a password. Don't post it in a public channel. Don't paste it into a service that keeps URL history. If you have any doubt, add --password so the recipient also needs a passphrase you send through a different channel.

Hardening this fork carries vs. upstream ffsend

  • Server-supplied filenames are reduced to their basename before being joined with the user's output directory — a malicious uploader cannot escape your target dir via .. or absolute paths.
  • The history file is reopened with mode 0600 on every save (not just at create time), defending against an attacker who pre-creates the file world-readable.
  • An inverted-condition bug in History::remove was fixed; deletes and expired-entry cleanup now persist on autosave.
  • follow_url preserves the URL fragment across HTTP redirects, so the decryption key survives the tarnover/send /download/ → /dl/ 301-redirect path.

For broader Send-protocol crypto details see the upstream encryption notes. To report a vulnerability in this fork, see SECURITY.md.

Scripting

sndr is designed for unattended use. The three flags you almost always want in a script:

  • -I / --no-interact — fail fast instead of waiting for stdin
  • -y / --yes — assume yes for confirmations
  • -q / --quiet — print only the share URL on upload
set -e
URL=$(sndr -Iy upload -q backup.tar.gz)
echo "share: $URL"
sndr -I password "$URL" --password="$(pwgen 24 1)"

Or set the equivalents globally and forget about them:

export SNDR_NO_INTERACT=1 SNDR_YES=1 SNDR_QUIET=1

sndr exits non-zero on any failure, including expired shares and network errors, so set -e works as expected.

Build

git clone https://github.com/tarnover/sndr.git
cd sndr

cargo build --release -j2          # build the release binary
cargo clippy --no-deps             # lint
./target/release/sndr --version

cargo install --path . -f          # install into ~/.cargo/bin

Feature flags (all enabled by default unless marked):

Feature Default What it does
send3 ✓ Send v3 protocol (current servers)
send2 Send v2 protocol (older servers)
crypto-ring ✓ Pure-Rust crypto backend
crypto-openssl OpenSSL crypto backend (needs system OpenSSL)
clipboard ✓ --copy support via xclip / xsel / native API
history ✓ Local share history
archive ✓ Tar directories on upload, untar on download
qrcode ✓ Render share URLs as QR codes
urlshorten ✓ Built-in URL shortener integration
infer-command ✓ sndrput, sndrget, sndrdel symlink dispatch
no-color Disable colored output

Override with cargo install --no-default-features --features ....

Migrating from ffsend

If you already had ffsend installed and configured, here's the quick migration. Nothing happens automatically — sndr is a clean break, not a drop-in.

What changes Old (ffsend) New (sndr)
Binary name ffsend sndr
Env-var prefix FFSEND_* SNDR_*
History file ~/.cache/ffsend/history.toml ~/.cache/sndr/history.toml
Symlink dispatch ffput / ffget / ffdel sndrput / sndrget / sndrdel
Default host https://send.vis.ee/ https://snd.dx.pe/

Carry your share history over (one-time):

mkdir -p ~/.cache/sndr
cp ~/.cache/ffsend/history.toml ~/.cache/sndr/history.toml

Rename env vars in your shell rc:

sed -i 's/FFSEND_/SNDR_/g' ~/.bashrc ~/.zshrc 2>/dev/null

sndr and ffsend can coexist — different binary names, different config paths — so you can roll back at any time by switching back to the old binary.

Project status

This fork is maintained by tarnover to support the tarnover/send server fork. Upstream timvisee/ffsend remains the canonical implementation for users who want the broadly-packaged binary.

mozilla/send  →  timvisee/ffsend  →  tarnover/sndr (this repo)

Bug reports and PRs welcome at github.com/tarnover/sndr. See CONTRIBUTING.md for the contribution flow and SECURITY.md for vulnerability reporting.

Acknowledgements

  • Mozilla — designed and open-sourced the original Firefox Send protocol and codebase before discontinuing the service in 2020.
  • Tim Visée (@timvisee) — kept the protocol alive as both the timvisee/send server fork and the original timvisee/ffsend CLI that this rebrand started from.

License

GNU GPL-3.0. See LICENSE.