Enter a value and run the local tool.
Method and worked example
The tool trims outer whitespace, removes a recognized doi: prefix or doi.org/dx.doi.org wrapper, and checks for a 10-dot numeric registrant prefix, slash, and nonempty whitespace-free suffix.
doi:10.1000/182 becomes 10.1000/182 and the resolver URL https://doi.org/10.1000/182.
Scope and limitations
A plausible syntax result does not mean the DOI exists, resolves, is registered, or has correct metadata. No resolver or metadata request occurs.
Review the output before using it in academic, publishing, or identity workflows.