Custom Transfer Codes: Pick Your Own Slug Like FT-MEETING-ACME

File Tunnel ships three flavors of transfer code: random (WTT9Z8CFFQFK), memorable (FT-MEADOW-COPPER-LIGHT), and custom (FT-MEETING-ACME-Q4). The first two are great defaults; the third is the one Pro users reach for when they want the code itself to carry meaning.

With a custom code, the slug between hyphens is whatever you type. The receiver knows what the file is about before they even hit Receive — useful for batch handoffs, recurring deliveries, and anything where a self-documenting URL beats a self-documenting filename.

When a custom code is the right call

• Recurring weekly deliverables.FT-2026-W18-REPORT, FT-2026-W19-REPORT, and so on — clients can predict next week's code without asking.
• Per-client buckets.FT-ACME-FINAL for Acme, FT-MERIDIAN-DRAFTfor Meridian. The code is the channel; you re-use the slug across many transfers without confusion.
• Conference / event handouts.FT-PYCON-2026-SLIDES — a single human-typeable URL that the speaker can announce on stage and put in their last slide.
• Versioned drops. FT-LOGO-V3,FT-LOGO-V4 — the recipient sees the version in the code itself.
• Personal handoffs.FT-DAD-VACATION-PHOTOS. Family members type the phrase rather than copy a random string.

Slug rules

The server normalizes whatever you type, so you don't have to be precise:

• Allowed: A–Z, 0–9, hyphens, underscores, spaces. Underscores and spaces are converted to hyphens; adjacent hyphens collapse to one.
• Lowercase input is uppercased automatically.
• Optional FT- prefix on input is stripped before re-prefixing — both MEETING-ACME and FT-MEETING-ACME become FT-MEETING-ACME.
• Length: 3–32 characters in the slug body. The full code with prefix tops out at 35 chars.
• Uniqueness: If your slug is already in use by an active transfer, the server returns a clean "this code is taken" error so you can pick another. We don't silently fall back to a random code.

Custom vs memorable — which to use when

Both are Pro features and they're mutually exclusive per transfer. The decision tree:

• Custom when the code itself should describe the file (project name, client, date, version).
• Memorable when you don't care about the content tag and just want something pronounceable for a phone handoff (the curated word list keeps spelling unambiguous).
• Random when you're sending to a script, a power user who copies once, or you actively want the code to leak no information about the content.

How to enable a custom code

1. Activate Pro Pass on the device you send from.
2. On the Send tab, scroll the settings panel.
3. Toggle Custom code on. (This disables the Memorable code toggle — they're mutually exclusive.)
4. Type your slug in the input field that appears.MEETING-ACME-Q4 becomes FT-MEETING-ACME-Q4.
5. Pick your expiry, then send. If the slug is taken you'll see a 400 error inline and can pick a different one.

Privacy considerations

A custom code is more guessable than a random or memorable one. If you use FT-ACME-FINAL as your client-channel code repeatedly, anyone who knows the convention can try it between transfers. This isn't a vulnerability per se — the code only resolves while a transfer session is live, and rate limiting prevents bulk guessing — but for sensitive content, layer in password protection (also Pro). The combination of a known custom code and a separate passphrase reproduces the "something you know + something you have" pattern.

Reserved patterns we block

A handful of prefixes are blocked to keep things clean:

• FT-MEMORABLE-* — confusable with the memorable generator's output.
• Slugs that are only digits — confusable with order numbers.
• Profanity, slurs, and obvious abuse patterns are filtered server-side.

If your slug is rejected for one of these reasons you'll get a clear error — pick another and you're done.