#3 Product of the week · Launched December 16, 2025
Cert Decoder
Cert Decoder – free and simple Certificate Decoder
3thProduct of the week
FreeSecurity1,111 impressions#3 of its week
Cert Decoder - Free online tool to decode certificates in PEM format. Instantly extract and verify certificate details. No data leaves your browser.
Cert Decoder is a free browser-based tool that decodes PEM-encoded X.509 certificates and displays their details.
- for
- Developers and security engineers who need to inspect TLS/SSL certificates quickly
- pricing
- free
Key features
5 features of Cert Decoder
- PEM paste input — Paste a full PEM certificate including BEGIN/END markers and click Decode.
- Full field extraction — Shows issuer, subject, validity dates, serial number, signature algorithm, SANs, public key info and extensions.
- Client-side processing — All decoding runs in the browser; no data is sent to a server.
- Privacy guarantee — Your certificate data never leaves your computer.
- Educational info — Provides explanations of X.509 structure and common uses.
Use cases
- Verify a website's TLS certificate details before deployment
- Inspect a self-signed certificate for testing environments
- Check SAN entries and validity periods of a received certificate
- Debug certificate chain issues by viewing extensions
Cert Decoder vs alternatives
 Cert Decoder |  aikido |  Perfai Security |  BunkerWeb | |
|---|---|---|---|---|
| Best for | Client-side X.509 certificate decoding | General dev security utilities | App vulnerability discovery | Web traffic protection |
| Pricing | Free | Free | Free | Free |
| DevHunt upvotes | 1 | 65 | 30 | 20 |
| Launched | Dec 2025 | Dec 2024 | Jun 2026 | Dec 2024 |
- Cert Decoder vs aikido: Focuses on broader security tooling rather than specific certificate decoding
- Cert Decoder vs Perfai Security: Provides AI-driven vulnerability scanning, not certificate parsing
- Cert Decoder vs BunkerWeb: A web-application firewall, unrelated to certificate inspection
Cert Decoder FAQ
Do I need to install anything to use Cert Decoder?+
No, it runs entirely in your web browser using client-side JavaScript.
Is my certificate data stored or transmitted anywhere?+
No, the tool processes the data locally and never sends it to a server.
What certificate formats are supported?+
Only PEM-encoded X.509 certificates; include the BEGIN and END markers.
Can I decode multiple certificates at once?+
You can paste a PEM file that contains multiple certificates; the tool will decode each.
What information does the decoder display?+
Issuer, subject, validity period, serial number, signature algorithm, SANs, public key info, extensions and more.
Summarized by DevHunt from certdecoder.com · Oct 1, 2026. Details may change; check the official site.
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