# fyl.at

> Anonymous, temporary file sharing. Upload one file of up to 50 GB and get a link that expires after 5 minutes to 7 days. No account, no sign-up. It works in a browser and with the `fyl` command-line tool, which is the easiest way for an agent.

One link is one file: zip a folder first. A link works as soon as the upload starts; whoever opens it early gets the file once the upload is done. Files are deleted when their link expires, after a one-time link's download, or when the sender deletes them. fyl.at doesn't scan files, so only share files you are allowed to share, and only open files you expected.

## Install the CLI

- `curl -fsSL https://fyl.at/cli/install | sh` installs `fyl` to /usr/local/bin (Linux or macOS 11+, x86_64 or arm64).
- [Current version](https://fyl.at/cli/latest): the binaries and their `SHA256SUMS` are under `https://fyl.at/cli/<version>/`.
- `fyl --help` lists every option; `fyl --version` prints the version.

## Upload

- `fyl ./report.pdf` uploads the file and prints only its download link on stdout (progress with `-v` on stderr).
- `--expires 30m` sets the lifetime: from `5m` to `7d`, for example `30m`, `12h`, `3d` (default `1d`).
- `--once` allows a single download: the first complete download closes the link.
- `--password` requires a password: fyl asks for one (Enter generates one) or takes `FYL_PASSWORD` in scripts; `--json` includes a generated password.
- `--encrypt` encrypts the file on this device before the upload (end-to-end encryption, E2EE). The key is the part of the link after `#`, which browsers never send to fyl.at. Anyone with the full link can open the file; a lost key can't be recovered.
- `--manage` also prints the private management link, needed to delete the file. Keep it to yourself.
- `--json` prints one JSON object instead: `url`, `name`, `size`, `expiresAt`, `once`, plus `managementUrl`, `protected`, `password` or `encrypted` when they apply.
- An interrupted upload prints a `fyl … --resume VALUE` command that continues it within 24 hours.
- A link, resume value or management link given as `-` is read from stdin, which keeps it out of the process list.

## Upload with curl only (files up to 50 MiB)

A file of up to 50 MiB (52,428,800 bytes) is one part, so curl and jq can upload it in three requests: start the upload, send the part, complete it. Larger files have several parts; use the CLI, which also resumes them.

```sh
f=report.pdf
init=$(curl -fsS https://fyl.at/api/upload/init -H 'Content-Type: application/json' \
  -d "$(jq -n --arg name "$f" --argjson size "$(wc -c < "$f")" '{filename: $name, size: $size}')")
id=$(jq -r .uploadId <<<"$init"); key=$(jq -r .key <<<"$init")
etag=$(curl -fsS -X PUT "https://fyl.at/api/upload/part?uploadId=$id&partNumber=1" \
  -H "Authorization: Bearer $key" --data-binary @"$f" | jq -r .etag)
curl -fsS https://fyl.at/api/upload/complete -H 'Content-Type: application/json' \
  -d "$(jq -n --arg id "$id" --arg key "$key" --arg etag "$etag" '{uploadId: $id, key: $key, parts: [{partNumber: 1, etag: $etag}]}')"
```

- The last answer is the receipt: `url` is the download link, `managementUrl` the private management link (`https://fyl.at/#manage/<id>/<management key>`).
- Options go into the first request: `expiresIn` in seconds (300 to 604800, default 86400), `oneTime: true`, `password: "…"` (6 to 200 characters).
- The download link works from the first answer on (`.url` of `init`); it waits until the upload is complete.
- Delete: `curl -fsS -X DELETE https://fyl.at/api/transfers/<id> -H 'Authorization: Bearer <management key>'`.
- Encrypted uploads need the CLI (`fyl FILE --encrypt`).

## Download

- A plain link (`https://fyl.at/d/<id>/<name>`): `curl -fOJ 'https://fyl.at/d/<id>/<name>'` saves the file under its own name. Requests that ask for HTML (`Accept: text/html`) get the download page instead of the file.
- A link whose upload is still running answers 503 with `Retry-After`; `curl -fOJ --retry 120 '<link>'` waits for the file.
- A password-protected link: `curl -fOJ -u fyl '<link>'` asks for the password (the user name is ignored). Five wrong tries from one network pause it for 15 minutes.
- An encrypted link (`https://fyl.at/d/<id>#<key>`): `fyl download '<link>'` downloads, decrypts and verifies it, then prints the saved path. Without the key in the link, fyl asks for it (`FYL_KEY` in scripts); a protected file asks for its password (`FYL_PASSWORD`). Plain curl gets 409 `encrypted` and no file; `curl -fOJ '<link without #key>?dl=1'` saves the ciphertext, which `fyl decrypt fyl-<id>.age` opens.
- A one-time link closes after its first complete download. Link previews and HTML page requests don't use it up.

## Delete

- `fyl rm '<management link>'` deletes the file at once; its link stops working.

## Limits and errors

- One file per link, up to 50 GB; lifetimes from 5 minutes to 7 days.
- Per network and day: 500 uploads, 50 at a time, 250 GB uploaded, and 250 GB stored at once.
- API errors are JSON `{error, code}`; download links answer curl with a short plain-text reason. 429 and 503 carry `Retry-After`: wait and try again. 410 means the link is gone (expired, used up or deleted), 404 that there is no file at that link.

## Rules

- Share only files you have the right to share: no malware, no illegal content, nothing that infringes others' rights.
- To report a file, use the form at https://report.fyl.at/ (it checks that a person sends it).

## Optional

- [Privacy](https://fyl.at/privacy): what fyl.at stores, for how long, and what encrypted files keep from the server.
- [Report a file](https://report.fyl.at/): the report form for abuse and rights holders.