How to read a .REQ file online
Three steps, a few seconds.
Open your .REQ file
Drop it on the box or click to choose it. A bundle holding several certificates is split for you automatically.
Unlock if needed
A password-protected file asks for its export password. It is used only to unlock the file.
Check the details
Read the chain from your certificate up to the root, see every domain it covers, when it expires and copy its SHA-256 fingerprints.
What is a .REQ file?
What's inside .crt, .pem and .p12 files, in plain words.
A .req file is a Certificate Signing Request (CSR), a small encoded text block you send to a Certificate Authority to get an SSL/TLS or other digital certificate. Open it in any text editor or inspect the decoded fields with OpenSSL. The file is not secret; only your private key (.key) must stay protected.
Programs that open .REQ files
| Full name | Certificate Signing Request (CSR) — .req |
|---|---|
| Developer | Microsoft (certreq.exe on Windows); the underlying CSR is PKCS#10 (RSA Security / IETF) |
| First released | PKCS#10 (1990s); .req is the default CSR extension produced by Windows certreq |
| Category | Data & Other |
| MIME type | application/pkcs10 |
Related viewers
Other free tools to open and preview your files.
Frequently asked questions
Is it safe to open my .REQ file here?
Yes. Certificates are public by design, and decoding and signature checks run with the Web Crypto API.
What does “chain verified” mean?
Each certificate is signed by the one above it. The viewer checks those signatures mathematically, so you can see whether your server certificate, intermediate and root actually belong together - the most common cause of “incomplete chain” errors.
My .p12 / .pfx asks for a password. Which one?
The password chosen when the file was exported (for example from Windows, a browser or your CA's portal). Some files have an empty password - try leaving the field blank.
Why don't you show my private key?
A private key is the secret half of the certificate. Anyone who sees it can impersonate you, so the viewer only tells you that a key is present and what type and size it is.
Can it check if a certificate is revoked?
Not yet. Revocation (OCSP/CRL) needs to contact the certificate authority, which we keep for the server-side version of this tool.
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