PEM / CERT File Details Parser

Extract issuer, subject, validity, SANs, and key info from PEM/CERT text in seconds.

PEM / CERT File Details Parser

Extract certificate and key details from pasted PEM/CERT text.

Settings Prefilled examples
Tip: Include the full BEGIN/END lines. For chains, paste one block at a time.
Result Copy-ready
No output yet
Paste your PEM/CERT content and click Generate.
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About PEM / CERT File Details Parser

PEM / CERT File Details Parser for Certificates and Keys

Use this PEM/CERT parser to extract human-readable details from X.509 certificates and private keys without installing extra tooling. Paste your .pem, .crt, or .cert content and get the issuer, subject, validity dates, SAN entries, key type, key size, and optional fingerprints in a clean report you can copy or download.

How the PEM / CERT File Details Parser Works

The tool inspects the text you provide and detects whether it contains an X.509 certificate block (BEGIN CERTIFICATE) or a private key block (BEGIN PRIVATE KEY / BEGIN RSA PRIVATE KEY / BEGIN EC PRIVATE KEY). It then uses OpenSSL parsing routines on the server to read the structure and produce a consistent summary that is easy to validate and share with teammates.

Step-by-step

  • 1) Paste content: Copy the full PEM text from a file or clipboard, including the BEGIN/END lines, and paste it into the input box.
  • 2) Choose output: Pick Summary for a compact report or Verbose for an expanded view including common extensions and additional identifiers.
  • 3) Optional fingerprints: Enable SHA-256 fingerprints when you need a quick integrity check or want to compare the same cert across systems.
  • 4) Generate: The parser validates the block, extracts the fields, and formats the output as plain text for easy copying.
  • 5) Export: Copy the report to your ticket, runbook, or chat message, or download it as a TXT file for documentation.

Key Features

Certificate subject and issuer at a glance

Immediately see who the certificate is issued to (Subject) and who issued it (Issuer), including common fields like CN, O, OU, and C. This helps you verify that a certificate matches the hostname, organization, or environment you expect.

Validity window and expiration awareness

The parser highlights the Not Before and Not After timestamps so you can confirm when the certificate becomes valid and when it expires. This is useful for renewal planning, incident response, and avoiding outages caused by expired certificates.

Subject Alternative Names (SAN) decoding

Modern TLS relies on SAN entries rather than only the Common Name. The tool extracts DNS names, IP addresses, and other SAN values when present so you can confirm coverage for multi-domain certificates, wildcard certs, and internal services.

Private key inspection (type and size)

If you paste a private key block, the tool reports the key algorithm (RSA, EC, or DSA when applicable) and key size. This helps validate compliance requirements, verify that a key is sufficiently strong, and ensure the right key is being deployed.

Copy-ready report with optional fingerprints

Results are formatted as clean plain text. Enable SHA-256 fingerprints to quickly compare certificates across load balancers, containers, and endpoints, or to verify that a file was not replaced during deployment.

Use Cases

  • TLS troubleshooting: Confirm that the certificate served by a proxy matches the one you intended to deploy, including SAN coverage.
  • Renewal planning: Extract expiration dates and share a simple report with your operations calendar or ticketing system.
  • Security reviews: Verify key algorithm and size for baseline compliance checks before production rollouts.
  • DevOps handoffs: Provide issuer/subject and fingerprint details when moving certificates between teams, vendors, or environments.
  • Inventory cleanup: Identify unknown certificate files by reading their subject, serial, and validity without guessing.
  • CI/CD validation: Spot obvious mismatches early by pasting build artifacts and checking key properties in seconds.

Whether you are onboarding a new domain, debugging a broken handshake, or documenting infrastructure, a small, consistent certificate report reduces confusion and speeds up decision-making.

Optimization Tips

Paste complete PEM blocks

Include the BEGIN and END lines and keep line breaks intact. Missing headers, truncated base64, or accidental whitespace changes can prevent a successful parse. If you are copying from a terminal, ensure the full block is captured.

Prefer Verbose mode for audits

Summary mode is ideal for quick checks, but Verbose mode is better when you need to review extensions like Basic Constraints, Key Usage, Extended Key Usage, and Authority/Subject Key Identifiers. Use Verbose output in review notes and change requests.

Use fingerprints to compare deployments

When multiple systems appear to use “the same cert,” compare SHA-256 fingerprints rather than relying on filenames. Fingerprints are stable identifiers that help you confirm the exact certificate instance installed on different nodes.

FAQ

You can paste PEM-encoded X.509 certificates (BEGIN CERTIFICATE) and common PEM private key blocks (BEGIN PRIVATE KEY, BEGIN RSA PRIVATE KEY, BEGIN EC PRIVATE KEY). DER binary files must be converted to PEM first.

The tool focuses on extracting details from the file contents. Trust validation depends on your trust store and chain verification, which is typically handled by your operating system, browser, or a full OpenSSL verify step.

If you paste multiple CERTIFICATE blocks, the tool will attempt to parse the first certificate block for a clear, single report. For chain analysis, split blocks and parse them one by one so each certificate’s issuer and subject can be reviewed.

Treat private keys as highly sensitive. Only paste keys you are authorized to handle and avoid sharing outputs publicly. For best practice, use the tool in trusted environments and remove pasted data after generating the report.

Not every certificate includes the same extensions and metadata. Self-signed or minimal certificates may omit SANs or Key Identifiers, and some environments may not expose certain computed values depending on OpenSSL capabilities.

Why Choose This Tool?

This parser is designed for fast, practical workflows: paste a PEM block, get the details you need, and move on. It produces a consistent report that fits cleanly into tickets, audits, and runbooks, reducing the time spent reformatting OpenSSL output or digging through verbose command results.

By focusing on the most useful certificate and key attributes—identity, validity, SAN coverage, and key strength—you can quickly confirm whether a file is correct for the job. Use it as a lightweight companion to your existing security and deployment processes whenever you need clarity about a PEM or CERT file.