Long URLs with tracking parameters, deep paths and encoded characters are awkward in chat messages, slide decks, printed material and SMS. A short link fixes that, but it also hides the real destination, which is exactly why short links are popular with phishers. A responsible shortener has to be useful and refuse to become a disguise.
The URL Shortener on NetTools.tech creates a short link at https://nettools.tech/s/<code> with an optional custom alias and a fixed expiry. Before a link is created, the destination is checked: public domain, resolvable to public addresses, not on the SURBL or URIBL domain blocklists, not another shortener. There is no click tracking.
What is a URL shortener?
In simple terms
A URL shortener stores a long address under a short code. When someone opens the short address, the shortener's server looks up the code and tells the browser to go to the long address instead. The browser follows automatically, so the visitor ends up at the original page.
Technical background
The forwarding is an ordinary HTTP redirect as defined in RFC 9110: the server answers the request for the short URL with a 3xx status and a Location header containing the destination. Which status is used matters:
- 301 / 308 (permanent) can be cached by browsers and proxies indefinitely. If the link is later removed, cached clients keep going to the old destination.
- 302 / 307 (temporary) are not cached by default. Each visit asks the shortener again, so a deleted or disabled link stops working at once.
NetTools.tech uses 302 with Cache-Control: private, no-store, so expiry, deletion and abuse takedowns take effect immediately.
The other technical concern is abuse. A short link hides its destination, so shorteners are used to slip phishing and malware URLs past filters. Domain blocklists such as SURBL and URIBL list domains seen in spam and phishing; they are queried over DNS, much like the IP blocklists used for email.
Why use a URL shortener?
- Readable links in chat, SMS, presentations, printed material and QR codes.
- Temporary sharing of a link that should stop working after an event, a review period or a campaign.
- Clean handover of long URLs with many parameters that tend to break when copied or line-wrapped.
- No tracking. Unlike many commercial shorteners, NetTools.tech does not record who clicked, when or from where.
Who should use it?
- Admins and engineers sharing long documentation, dashboard or ticket links with colleagues.
- Trainers and speakers who need short links on slides that expire after the event.
- Support teams sending links to customers by SMS or phone.
- Anyone who wants a short link without an account or click profile.
If you need click statistics, permanent links or links on your own domain, a self-hosted shortener or a commercial service is the better fit.
How the URL shortener works
When you submit a long URL, the NetTools.tech server runs these steps:
- Destination policy. The URL must be
httporhttps, at most 2,048 characters (without a scheme,https://is assumed), with a domain name rather than an IP address, at least two labels (e.g.example.com), and port 80 or 443 if a port is given. URLs with embedded credentials, private or internal names, links to NetTools.tech itself and links to well-known shorteners such as bit.ly, tinyurl.com, t.co or goo.gl are refused, because chaining shorteners would hide the real destination from the checks. - Alias and expiry. An optional alias must be 3–32 characters from
A–Z a–z 0–9 - _. It is lower-cased, and reserved names (for exampleadmin,login,support,verify,nettools) are refused. Expiry must be 1 day, 7 days, 30 days or 1 year. - DNS check. The destination host must resolve, and every address it resolves to must be public. A host that does not resolve or points to private addresses gets no link.
- Blocklist check. The hostname and its parent domains (up to four names, e.g.
a.b.example.com,b.example.com,example.com) are queried on SURBL multi and URIBL multi, and on Spamhaus DBL when the server has a Spamhaus DQS key configured. If any list reports the domain, the link is refused. If no list could give a "not listed" answer, the link is also refused, so an unreachable blocklist never lets a link through unchecked. - Creation limits. At most 10 links per hour and 30 per day per client, plus a global daily cap.
- Storage. Without an alias, a random 7-character code is generated from lower-case letters and digits that excludes the easily confused
0,o,1andl. The record stores the code, destination, creation time, expiry and a SHA-256 hash of a random delete token. The token itself is returned to you once and never stored. - Redirect.
GETorHEADonhttps://nettools.tech/s/<code>looks up the code (case-insensitively) and answers 302 to the destination. Expired links answer 410 with "This short link has expired", disabled links 410 with "This short link has been disabled", unknown codes 404. Redirect requests are rate-limited per client.
Expired rows are deleted by a cleanup that runs every hour.
How to use the NetTools.tech URL Shortener
- Open the URL Shortener.
- Paste the destination into Long URL.
- Optionally enter a Custom alias, for example
team-offsite. Leave it empty for a random code. - Choose Expires after: 1 day, 7 days, 30 days (default) or 1 year.
- Press Shorten URL. The destination checks take a few seconds.
- Copy the short link with Copy, or test it with Open.
- Copy the delete token with Copy token and keep it somewhere safe if you may want to remove the link early. It is shown only once.
- To delete a link later, scroll to Delete a short link, enter the short link or its code and the token, and press Delete link.
Preview with sample data shows the result layout with a made-up link on the reserved short.example domain; it creates nothing.
Understanding the results
| Result | Meaning | What to look for |
|---|---|---|
| Short link | https://nettools.tech/s/<code> | The code is your alias or a 7-character random code |
| Redirects to | The stored destination, normalized | Check that it is exactly the URL you meant, including parameters |
| Alias | Your alias, or "Random code" | Aliases are stored in lower case |
| Expires | Local date and time when the link stops working | Choose a longer expiry for printed material |
| Blocklist checks | Each list's answer: not listed, listed or unavailable | "unavailable" for one list is fine as long as another answered "not listed" |
| Delete token | Secret that allows deleting the link | Shown once; without it the link stays until it expires |
Example: a link for a workshop
You want to share https://docs.example.com/workshops/2026/network-monitoring/lab-setup?section=prerequisites&lang=en with participants for one week.
- Long URL: the address above
- Custom alias:
lab-setup - Expires after: 7 days
The result shows https://nettools.tech/s/lab-setup, "Redirects to" with the full URL, the expiry date one week from now, and blocklist checks such as SURBL multi: not listed · URIBL multi: not listed. A request for the short link returns:
HTTP/1.1 302 Found
Location: https://docs.example.com/workshops/2026/network-monitoring/lab-setup?section=prerequisites&lang=en
Cache-Control: private, no-store
X-Robots-Tag: noindexEight days later the same short link answers 410 Gone with an explanation page, and the alias lab-setup can be used again.
Common use cases
- Sharing long dashboard, wiki or ticket links in chat and email.
- Short links on slides and handouts that expire after the event.
- SMS or phone support, where long URLs are hard to type.
- QR codes that should point to a short, readable address.
Troubleshooting
"Short links need a destination with a domain name, not an IP address"
IP-address destinations are refused because they bypass domain blocklists. Use the host name of the server.
"Short links can only point to the standard web ports (80 and 443)"
Destinations on ports such as 8080 or 8443 are not accepted by the shortener. Publish the target on a standard port or share the long URL directly.
"Links to other URL shorteners are not accepted"
Expand the other short link first (the Redirect Checker shows where it leads) and shorten the final destination.
"The destination host does not resolve to a public address"
The host has no DNS record, a typo, or points to private addresses. Check it with DNS Lookup.
"The destination is listed on …"
A domain blocklist reports the domain. If it is your domain and you believe the listing is wrong, check it with MultiRBL and follow the list operator's removal process.
"Could not be checked against domain blocklists right now"
No blocklist answered. Nothing is created without a check; try again later.
"The alias … is already in use" or "is reserved"
Pick another alias. Reserved names exist so that short links cannot look like official login or support pages.
Rate limit messages
At most 10 links per hour and 30 per day per client. Wait, or reuse existing links.
Common mistakes
- Not saving the delete token. It is shown once and only its hash is stored; nobody can recover it.
- Choosing too short an expiry for print. Printed links outlive campaigns; expired links answer 410.
- Expecting statistics. There is deliberately no click counter.
- Shortening a link that will change. Links cannot be edited; delete and recreate instead.
- Using short links to hide destinations from recipients. Many people and filters distrust short links; for sensitive messages, the full URL is more trustworthy.
Limitations
- No click statistics, no editing, no custom domains and no permanent links (the longest expiry is one year).
- Blocklist checks happen once, at creation time. A destination that turns malicious later is not re-checked automatically; the operator can disable abusive links after reports.
- The checks look at the destination domain only. They cannot judge the content of the page, and a clean domain can still host unwanted content.
- Destinations must be public, on ports 80 or 443, and reachable by DNS from the NetTools.tech server at creation time.
- Creation and redirect requests are rate-limited, so the service is not suitable for bulk or automated link generation.
Security & privacy
The long URL, alias and expiry are sent to the NetTools.tech server and stored in its database until the link expires or is deleted. The server does not store who created a link, and it does not log clicks per link. The destination domain is looked up in DNS and queried on the domain blocklists (SURBL, URIBL and, when configured, Spamhaus DBL), so those operators see a DNS query for the domain, not the full URL.
Do not shorten URLs that contain secrets, such as password reset links, API keys, session tokens or private document links with access keys in the query string: anyone who gets the short link gets the full URL. Treat the delete token like a password for that link.
Related tools
- Redirect Checker – see where any short link really leads before you click (guide).
- URL Encoder / Decoder – build and inspect long URLs with encoded parameters (guide).
- Open Graph Checker – check how the destination page will look when shared (guide).
- MultiRBL – look up a domain on many blocklists (guide).
Summary
The NetTools.tech URL Shortener turns a long public URL into an expiring nettools.tech/s/ link served with an uncached 302 redirect. Destinations are screened before creation (public DNS, no IPs or credentials, no other shorteners, SURBL/URIBL), links expire after 1 day to 1 year, and a one-time delete token lets you remove a link early. It stores no click data, which also means it offers no statistics.
Frequently asked questions
How long do NetTools.tech short links last?
You choose 1 day, 7 days, 30 days or 1 year when you create the link; 30 days is preselected. After that the link answers with a page saying it has expired, and the stored destination is deleted by an hourly cleanup.
Can I choose my own short code?
Yes. Enter an alias of 3 to 32 letters, digits, hyphens or underscores. Aliases are not case-sensitive and are stored in lower case; a few names such as admin, login or support are reserved, and an alias already used by a live link is refused.
Why was my link refused?
The destination must be a public http or https URL with a domain name on port 80 or 443 that resolves only to public addresses. IP-address destinations, URLs with embedded credentials, links to NetTools.tech itself or to other URL shorteners, and domains listed on SURBL or URIBL are refused.
Does the shortener track clicks?
No. A link record holds only the code, the destination, the creation and expiry times, a hash of the delete token and an operator disable flag. There is no click counter, no creator IP and no visitor profile.
How do I delete a short link?
When you create a link you get a delete token, shown only once. Enter the short link (or its code) and the token in the Delete a short link section; the link stops redirecting immediately.
Can I change the destination of an existing short link?
No. Links cannot be edited. Delete the old link with its token and create a new one; if you want the same alias, it becomes available again once the old link is deleted.
Which redirect status does a short link use?
Short links answer with 302 Found and Cache-Control: private, no-store. A temporary, uncached redirect makes sure a deleted, expired or disabled link stops working at once instead of living on in browser or proxy caches.