Acao Checker
Use Acao Checker on AboveTool to parse URLs, headers, DNS/WHOIS text, IPs, and certificates in your browser — free, private, no signup.
Acao Checker
evaluates Access-Control-Allow-Origin rules against a request Origin
Runs in your browser. Live DNS/WHOIS registries are not queried unless a mode explicitly uses a public lookup API.
About Acao Checker
Acao Checker evaluates Access-Control-Allow-Origin rules against a request Origin. It works by compares ACAO values (*, exact origin, or null) with the Origin header. Wildcard * cannot be combined with credentials in browsers. Acao Checker runs free in your browser at abovetool.com — no signup, instant results.
How to use
- Enter the inputs for this network utility (two IPs, a single address, headers, PEM, and so on).
- Click Compare IPs, Lookup, Convert, or Run depending on the tool.
- Review the on-page result (including bit diffs or maps where shown), then copy or download.
Features
- Mode-specific forms for headers, URLs, IPs, DNS, and certificates
- Client-side parsers and builders — no upload required
- Copy or download results instantly
- Unique tool copy with practical tips for each utility
Frequently asked questions
What is Acao Checker for?
Acao Checker is evaluates Access-Control-Allow-Origin rules against a request Origin.
How does Acao Checker calculate the result?
It calculates compares ACAO values (*, exact origin, or null) with the Origin header.
Any tips for using this calculator?
Wildcard * cannot be combined with credentials in browsers.
Is Acao Checker free on AboveTool?
Yes. Acao Checker is free to use on abovetool.com with no account required, and results are calculated instantly in your browser.