Certificate Decoder
How to Decode Certificates Locally on your Mac
Certificates can reveal internal services, hostnames, issuers and infrastructure details. CodeSwissKnife decodes certificate material locally, without uploading PEM or DER files to a website.
Why decode certificates locally?
Certificate text and binary files can expose private infrastructure. Local decoding keeps certificate material in memory on your Mac.
Inspect common certificate formats
Certificate Decoder accepts PEM, bare Base64 DER, CER, CRT and DER files, including multiple-certificate PEM chains.
Use it during TLS debugging
Use Certificate Decoder beside HTTP Client, Base64 String Encode/Decode and Date tools when checking validity, issuers, subjects and chain details.
Use Certificate Decoder offline on macOS
Download CodeSwissKnife to keep this encoder or decoder and the rest of your developer workflow tools local on your Mac.