Certificate Monitor

How to use

SoftPerfect Certificate Monitor is a free desktop application that monitors TLS/SSL certificates on hosts you specify. It periodically connects to each host, retrieves the certificate and its chain, and evaluates overall health with a letter grade from A to F. The application runs entirely on your computer — your domain list and certificate details never leave your machine.

Getting started

When you first launch the application, the main window is empty. To begin monitoring, click Add Host on the toolbar.

The main window before any hosts have been added.

In the Add Host dialogue, enter the host address (a domain name or IP address), an optional display name, and the port number. Port 443 (HTTPS) is used by default, but you can choose other common TLS ports from the drop-down list or type a custom port number.

Adding a host to monitor.

Once a host is added, Certificate Monitor immediately connects to it, retrieves the TLS certificate, and displays the results. You can add as many hosts as you need and they will all be checked periodically at the configured interval.

Main window

The main window is divided into two areas: the host list at the top and the detail panel at the bottom. The host list can be displayed as a table or as tiles, and the detail panel shows certificate information for the selected host.

Table view with the certificate detail panel.

Table view

The table view shows one row per host with the following columns:

• Name — The display name or host address, with a status icon indicating the current state.
• Host — The host address being monitored.
• Grade — A letter grade from A (excellent) to F (critical) evaluating the overall certificate health.
• Expires — The number of days until the certificate expires, followed by the expiry date.
• Status — A text label showing the current certificate status (OK, Expiring, Expired, Error, etc.).

Click a column header to sort the list by that column. Use the filter box at the top to quickly find hosts by name or address.

Tile view

The tile view shows each host as a compact tile displaying the grade, host name and expiry information. Tiles are colour-coded by status. Switch between table and tile views using the Table and Tiles buttons on the toolbar. You can choose between small, medium and large tile sizes in Settings.

Detail panel

When a host is selected, the detail panel below shows two tabs:

• Certificate — Displays the certificate fields: Subject, Issuer, SANs (Subject Alternative Names), Serial number, validity period, SHA-256 fingerprint and key type. If a full chain was retrieved, each certificate in the chain is shown.
• History — Shows a log of past checks, including any certificate renewals (detected by serial number changes) and status transitions.

You can show or hide the detail panel using the Details button on the toolbar.

Grades

Each host receives a letter grade based on its certificate health:

• A — Excellent. The certificate is valid, trusted, not expiring soon, and uses a strong key.
• B — Good, but a minor issue is present, such as the certificate expiring within 30 days.
• C — Acceptable, but attention is needed. The certificate may be expiring soon or using a weaker key.
• D — Poor. Significant issues found, such as an untrusted chain or very short remaining validity.
• F — Critical. The certificate has expired, the host is unreachable, or the TLS connection cannot be established.

Settings

Open the settings dialogue by clicking Settings on the toolbar. Settings are divided into three tabs.

General

General settings: startup, check interval and data retention.

Start minimised

Launch the application minimised to the taskbar or dock.

Start with system

Automatically start Certificate Monitor when you log in.

Minimise to tray

When minimised, the application hides to the system tray instead of remaining on the taskbar.

Check interval

How often to recheck all certificates. The default is every 24 hours.

Timeout

The maximum time in seconds to wait for a TLS connection to a host.

Data retention

How long to keep check history in the database. Older entries are automatically removed.

Notifications

Notification settings: desktop alerts for certificate events.

Show desktop notifications

Enable or disable all desktop notifications. When enabled, you can choose which events trigger a notification:

• Certificate expiring (30 days) — A certificate will expire within 30 days.
• Certificate expired — A certificate has already expired.
• Connection errors — The host could not be reached or the TLS handshake failed.
• Host recovery — A host that previously had errors is now responding normally.

Appearance

Appearance settings: tile size, theme and colour scheme.

Tile size

Choose between small, medium and large tiles for the tile view.

Theme

Select Light, Dark or System to match your operating system’s theme.

Colour scheme

Pick a colour palette for the tile view. A preview tile is shown below the drop-down so you can see how it looks.