How do I pick a good custom back-half for a short link?
A good custom back-half is short, relevant to the destination, easy to say out loud, and never a guessable word if the link should stay private.
Shortlen Editorial · · 3 min read
The short answer
A good custom back-half is short (under 15 characters is a safe target), spelled the way it sounds, and tells people something about where the link goes — a campaign name, a product, an event. Avoid random guesses or personal names for anything you'll say out loud, and avoid real words entirely for links that should stay hard to find.
Key points
- A custom back-half is the part of a short link after the domain — the 'sale' in shortlen.com/sale — and it's the one part of the link people actually read.
- Short and sayable beats clever: a back-half someone can repeat correctly after hearing it once does its job.
- Match the back-half to the destination (a campaign, a product, an event) so the link is self-explanatory before anyone clicks.
- Capitalization and look-alike characters (1/l/I, 0/O) cause real mistakes when a back-half is read aloud or handwritten — avoid mixing them.
- For anything that shouldn't be easy to find or guess, skip a memorable word altogether and let the shortener generate a random one instead.
On this page
The back-half is the only part of a short link a person actually reads before deciding whether to trust it, so the short version of good advice here is: keep it short, make it sound like what it is, and don’t use a real word at all if the link needs to stay hard to guess.
What makes a back-half easy to use?
A back-half earns its keep when someone can hear it once and type it correctly later. That means keeping it under about 15 characters, using lowercase letters consistently (back-halves are usually case-sensitive, so Sale and sale can be two different links), and avoiding characters that look alike when spoken or handwritten — 1, l and I, or 0 and O. A back-half like webinar-oct reads and repeats cleanly; wB1n4r_Oct! does not, even though both might technically work.
Should the back-half describe the destination?
Yes, whenever the link is meant to be shared openly. A back-half like shortlen.com/pricing or shortlen.com/webinar-oct tells someone where they’re about to go before they click, which builds the same kind of trust a branded link does more broadly. Match it to the specific thing it points to — a campaign, a product, a date — rather than a generic word like link or click that could mean anything.
When should I avoid a memorable back-half?
Skip a real-word back-half entirely for anything that shouldn’t be easy to find or guess — an unlisted file, a private invitation, a link shared only with one person. A memorable back-half is, by definition, guessable: if shortlen.com/sale exists, someone might reasonably try shortlen.com/sale2 or shortlen.com/newsale too. For links like that, a random generated back-half is the safer default.
A quick checklist before you set one
| Question | If yes |
|---|---|
| Will someone need to say this back-half out loud or type it from memory? | Keep it short, lowercase, and free of look-alike characters |
| Does the link point to something specific (a campaign, a product, an event)? | Name the back-half after that thing, not a generic word |
| Does the link need to stay hard to find or guess? | Skip a real-word back-half; use a random generated one instead |
| Might you reuse a similar link next year or next campaign? | Add a short qualifier now (a year, a version) rather than overwrite later |
What to do next
Pick the back-half the way you’d pick a hashtag: short enough to say once, specific enough that it only fits one thing. If you’re choosing one for a link you plan to put in print or read aloud, test it by saying it to someone else and asking them to type what they heard. See what a branded link is for how the back-half fits into a full short link, or get in touch if you’re setting one up and want a second opinion.
Questions people ask
Can two different short links use the same custom back-half?
No — a back-half only works if it's unique on that domain, the same way two pages can't share one URL. If the one you want is taken, try adding a short qualifier (a year, a region, a version) rather than an unrelated word.
Does the custom back-half affect the site's SEO?
Only indirectly. Search engines rank the destination page, not the short link's back-half, but a back-half that matches the destination (like /webinar for a webinar sign-up) makes the link trustworthy enough that more people actually click it.