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WasyTech
AvailableOpen SourceMIT

SSL Certificate Decoder

Decode X.509 certificates locally.

Pasting internal SSL certificates into random online decoders is a major security risk. This utility parses ASN.1 DER structures entirely client-side, extracting subjects, issuers, and expiration dates without your certificate ever leaving your machine.

  • Web
Open SourceLocal processingNo account

Downloads for this utility are being prepared.

Core features

Included in the free core utility.

  • Pure client-side ASN.1 parsing
  • Extracts Subject Alternative Names (SANs)
  • Calculates exact time until expiration

Privacy & data handling

This utility processes data locally on your device wherever technically possible.

Processing
Local, on your device
Account
Not required
Internet
Works offline
Telemetry
No telemetry

Details

Category
Developer Tools
Platforms
Web
License
MIT

Frequently asked questions

What does Cert Decoder do?

Pasting internal SSL certificates into random online decoders is a major security risk. This utility parses ASN.1 DER structures entirely client-side, extracting subjects, issuers, and expiration dates without your certificate ever leaving your machine.

Is Cert Decoder free?

Yes. Cert Decoder is free to use.

Is Cert Decoder open source?

Yes. Cert Decoder is open source under the MIT license.

Does Cert Decoder require an account?

No. Cert Decoder does not require an account.

Does Cert Decoder send my data anywhere?

Cert Decoder has no telemetry. Processing happens locally on your device.

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