Skip to tool
All tools
FeuTex · free tools runs in-browser no bloat built by LiMiT

UUID Checker

Paste one or many UUIDs (or a whole block of text) to validate them instantly. This tool can extract UUIDs, detect version/variant, and normalize to the canonical 8-4-4-4-12 form.

Category: Developer · URL: /tools/uuid-checker.html 


    
  



          

          

            Privacy: runs locally in your browser. No uploads, no tracking scripts.
          

        

      


      
    


    

      
How to use

      
Use it in strict mode for exact canonical UUIDs, or enable extraction to scan text for embedded UUIDs.
  1. Paste UUIDs (one per line) or any text into the input.
  2. Optional: enable Extract UUIDs from text to auto-find UUID-like patterns.
  3. Click Validate to see valid/invalid entries with version and variant.
  4. Click Normalize to output canonical lowercase UUIDs (valid entries only).

      

        Keywords this page targets (natural cluster): uuid checker, uuid validator, guid checker, validate uuid v4, uuid version checker, uuid variant checker, is this a valid uuid, extract uuids from text, normalize uuid, uuid format 8-4-4-4-12, urn uuid validator, uuid with braces validator, rfc 4122 uuid checker, uuid v1 validator, uuid v5 validator, uuid regex test, bulk uuid validation, uuid lowercase uppercase, canonical uuid format, guid vs uuid validator
      

      

        Secondary intents covered: Validate a single UUID or a list of UUIDs, Extract UUIDs from logs or pasted text, Identify UUID version (v1–v5) from an existing value, Check the UUID variant (RFC 4122 vs others), Normalize UUIDs to a consistent canonical format, Quickly generate a random UUID v4 for testing, Copy validation results for bug reports or CI logs, Find which entries in a batch are invalid
      

    


    

      
FAQ

    
What UUID formats does this tool accept?
It accepts canonical UUIDs (8-4-4-4-12), plus optional urn:uuid: prefixes and surrounding braces {...} unless strict mode is enabled.
What does “strict canonical only” mean?
Strict mode requires exactly xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (hex + hyphens only), with no URN prefix and no braces.
How do you detect the UUID version?
The version is the first hex digit of the 3rd group (for example, 4 in ....-....-4xxx-....-............).
What UUID variant should I expect for RFC 4122?
RFC 4122 UUIDs have the first hex digit of the 4th group in 8, 9, a, or b.
Can I validate multiple UUIDs at once?
Yes—paste one per line (or separated by spaces/commas). The output shows totals and which entries are invalid.
Does this tool send my UUIDs to a server?
No. Validation runs locally in your browser and does not make network requests.
What does “Normalize” do?
It outputs only the valid UUIDs converted to lowercase canonical form, one per line.