An expired certificate is the most avoidable outage there is. The date is known months ahead, the renewal is usually automated, and it still takes sites down every week — because nothing was watching, or because the thing watching only looked at part of the problem.
From $5 a month · No check quotas · Set up in under a minute
What is the best SSL monitoring tool?
It depends on what you are protecting against. For certificate expiry at scale on no budget, Red Sift Certificates Lite is the strongest option and it is free for 250 certificates. For certificate chain problems, Sematext validates the intermediate and root as well as the leaf. For certificates issued without your knowledge, SSLMate Cert Spotter is the specialist. For certificates as one of several things you need watched on one bill, that is where we place ourselves.
Two things have changed about certificate monitoring. Certificate lifetimes keep shortening, so the number of renewals you depend on has multiplied — and Let's Encrypt has stopped sending expiration emails, which for a lot of small sites was the only safety net behind the automation.
This list is published by MonitoringDaddy and we make one of the eleven tools on it. We have put ourselves first on a specific and narrow criterion, stated below, and where another tool is better at a job we have said so in its entry — including the ones that beat us outright. A list that ranks its own publisher first without telling you is not worth reading, so this one tells you.
Every price here was checked against the vendor's own pricing page in September 2026. Third-party listing sites are frequently months out of date in this category, and several of them are wrong about at least one tool on this list right now.
Certificate monitoring is four different jobs, and no tool is best at all of them.
Most "best SSL monitoring" lists rank on feature count, which rewards breadth and tells you nothing. These are ranked on value for the most common situation: you have a set of sites, their certificates renew automatically, and you want to be told before one of them does not. That is the criterion, and it is why we rank ourselves first — certificates here come with uptime, domain expiry, page changes and cron heartbeats on one bill from $5 a month.
It is also why that ranking flips the moment your situation is different. If certificates are literally the only thing you monitor, a free dedicated tool beats a paid general one. If your risk is mis-issuance rather than expiry, a Certificate Transparency monitor is the only correct answer and nothing else on this list substitutes for it.
| If your problem is… | The right kind of tool | Best on this list |
|---|---|---|
| A certificate quietly expiring | Expiry monitoring with a warning window | Red Sift Lite (free) or us (configurable) |
| An expired intermediate certificate | Full chain validation | Sematext Synthetics |
| A certificate you never ordered | Certificate Transparency monitoring | SSLMate Cert Spotter |
| Not knowing what certificates you have | Discovery | Red Sift Lite or KeyChest |
| Hundreds of certificates on a budget | Per-account pricing | CertPost |
Ranked for the common case — certificates alongside everything else. Each entry says who it is actually for.
From $5 a month for 25 monitors, where a monitor can be a certificate, an uptime check, a domain expiry watch, a page content watch or a cron heartbeat. Certificate warning windows are configurable from 1 to 60 days, and we alert both when a certificate has already expired and when the certificate check itself fails. What we do not do: validate the certificate chain, monitor Certificate Transparency logs, discover certificates for you, or reach certificates on internal hosts. If any of those is your actual requirement, one of the tools below is the better buy. Try MonitoringDaddy — plans from $5 a month.
Free for up to 250 certificates, with daily HTTPS scans that discover endpoints across your domains rather than making you list them. It is the recommended certificate monitoring service of Let's Encrypt, which is a meaningful endorsement from an organisation with millions of subscribers renewing every 90 days. The one real limitation is that expiry alerts are fixed at seven days — tight if a renewal needs anyone else's approval. For pure certificate expiry at scale with no budget, use this.
$2 per HTTP monitor, $7 per browser monitor, no overage charges. It validates every certificate in the chain — leaf, intermediate and root — alerts at 28, 14, 7 and 3 days on any of them, verifies the issuing authority is the one you expected, and checks for certificate changes every ten minutes. An expired intermediate takes a site down while your own certificate looks perfectly healthy, and this is the tool on the list that catches it.
$29 a month for unlimited certificates, which is the right pricing model once you pass about a hundred of them and the wrong one below thirty. It checks from outside the way a visitor does, follows the whole chain, and includes domain expiry on every plan including the free three-certificate tier. The Agency plan at $79 adds 15-minute checks and per-client status pages.
Free for 2 certificates, then $17 a month for 20 rising to $136 for 500. Expiry is the least interesting thing it does: it alerts on certificate changes, on suspicious issuance for your domains, and it monitors internal, private and self-signed certificates that no public scanner can reach. Private certificate support needs the $35 Growth tier.
From $15 a month for 20 endpoints, rising steeply to $100 for 150 and $500 for 1,000. It watches the public Certificate Transparency logs and tells you when a certificate is issued for your domain that you did not order — which is either shadow IT or someone preparing to impersonate you. The certspotter CLI is open source, so the core can be self-hosted. This is a security product, not an uptime tool, and pricing it against expiry monitors misreads it.
The free plan covers 10 uptime monitors plus one each of page speed, server, domain and SSL, which makes it the only genuinely free general monitoring tool here that watches a certificate. Superior at $20.41 a month raises that to 100 monitors with 50 SSL and 50 domain monitors, and Business at $66.66 adds sub-accounts for agencies.
From $17 a month for 2 sites up to $439 for 200, with every feature on every plan. Certificate health sits alongside broken link scanning, mixed content detection, Lighthouse reports, DNS records, DNS blocklist checks, domain expiry and cron checks — all per site. Expensive if you have many low-value sites, excellent if you have a few that genuinely matter.
Free for personal use, enterprise by quote. It finds certificates rather than waiting for you to list them, tracks each from issuance to expiry, and adds renewal and deployment automation plus a proxy for internal networks. The catch is commercial: business pricing is not published, so evaluating it starts with a sales conversation.
Certificate monitoring alongside genuinely excellent on-call and incident management, with status pages to match. The certificate side is competent rather than deep; you would choose this because you need an escalation rota, and the certificate checks come along with it.
Full-stack observability with certificate monitoring as one component among many, global checking and licence-based pricing. A great deal to configure and a great deal of product, which is the right trade only if you will use the rest of it.
Four situations that cover most people looking at this list.
Red Sift Certificates Lite. 250 certificates free, with discovery, and nothing on this list competes with free at that scale. Accept the seven-day warning window or pair it with something else.
This is the case we built for. Certificates, domains, uptime, page content and scheduled jobs from one $5 account, with warning windows you choose.
Sematext or CertPost. Both follow the whole chain. A monitor that only reads your own certificate will report everything as fine while browsers refuse the connection.
SSLMate Cert Spotter, and nothing else on this list is a substitute. Certificate Transparency monitoring is a different capability from expiry monitoring, and only a handful of products do it at all.
These separate a real certificate monitor from a checkbox on a feature list.
More tools than you would expect only alert inside a window before expiry. Once the date passes, the condition stops matching and the worst possible state produces silence. Ask specifically.
A monitor pointed at a host that no longer resolves is not monitoring anything. If it reports nothing rather than reporting a failure, you have a monitor that has quietly stopped being one.
Browsers reject the connection if any certificate in the chain has expired. Most tools read the leaf only.
Seven days is fine for an automated renewal and useless if a purchase order is involved. A fixed window is a constraint on your process, not just a setting.
Set up an alert that warns you before a certificate expires.
Point it at the hostname you want watched. It does not need an uptime monitor on the same host — a certificate monitor stands on its own.
Anywhere from 1 to 60 days before expiry. Match it to how long a renewal actually takes in your organisation, not to how long it takes when nothing goes wrong.
Email, webhook, Slack, Teams, Discord, Telegram or SMS on suitable plans. Send certificate warnings somewhere a person reads, not somewhere they accumulate.
A lapsed domain registration ends a site as completely as a lapsed certificate, and it is a separate monitor with its own window of 1 to 180 days.
Typically about 2 minutes from start to finish.
Uptime monitors, watched pages and heartbeats each get their own allowance, so adding a page watch never costs you a monitor. SSL and domain checks ride along with the monitor they belong to and use nothing extra.
| Plan | Monitors | Watched pages | Heartbeats | Fastest interval | Alert channels | Price |
|---|---|---|---|---|---|---|
| Free | 1 | 1 | 1 | Every 30 minutes | 1 email address | $0 |
| Founding Member first 20 only | 25 | 25 | 25 | Every 5 minutes | Email + webhook & chat | $5/mo |
| Basic | 10 | 10 | 10 | Every 10 minutes | Email + webhook & chat | $8/mo |
| Growth | 50 | 50 | 50 | Every 5 minutes | Email + webhook & chat | $19/mo |
| Pro | 100 | 100 | 100 | Every 60 seconds | Email + webhook & chat | $34/mo |
Annual billing is cheaper on every paid tier. The pricing page is the authoritative list.
Every recorded change is compared word by word and kept with a before-and-after image. This is the real output, shown with worked example data.
Price fell from $49 to $39, and an annual discount was added.
The item is available again and the basket button returned.
A new subprocessor was added in another jurisdiction.
The free plan sends to one email address. Every paid plan adds the chat and webhook channels below, with 2 to 10 destinations depending on the plan. However many alerts you receive, the price does not change — nothing here is metered or charged per alert.
There are no voice calls and no SMS. If a phone call at 3am is a hard requirement, say so before you subscribe — we would rather tell you now than refund you later.
Red Sift Certificates Lite, by a clear margin — 250 certificates free with automatic discovery, and it is the recommended certificate monitoring service of Let's Encrypt. StatusCake's free plan also includes one SSL monitor alongside ten uptime monitors if you want both in one place.
Because automation fails quietly. A renewal can succeed and never be deployed, a cron job can stop running, a DNS validation can break, or a card on file can expire. The renewal working ninety-nine times is what makes the hundredth failure invisible.
A certificate chain includes intermediate and root certificates as well as your own. If an intermediate expires, browsers reject the connection even though your certificate is valid — and a monitor that only reads your certificate will report everything as healthy. Sematext and CertPost check the full chain; most tools do not.
Certificate Transparency logs are public records of every certificate issued by a trusted authority. Monitoring them tells you when a certificate is issued for your domain that you did not request, which can indicate misconfiguration or impersonation. SSLMate Cert Spotter is the dedicated tool for this.
Long enough to complete your actual renewal process. For a fully automated Let's Encrypt renewal, seven days is plenty. For a certificate that needs purchasing and approval, thirty days is closer to right. This is why a configurable window matters.
Many do, with widely varying depth. Some treat certificates as a first-class monitor type with their own expiry windows; others check certificate validity as a side effect of an HTTPS request and cannot warn you in advance at all. Check which kind you are buying.
No. That change is a large part of why third-party certificate monitoring became necessary for small sites that had been relying on those emails as their safety net.
Only with a tool built for it. Most monitoring runs over public HTTPS and cannot reach an internal host. TrackSSL offers private certificate monitoring on its Growth tier and KeyChest uses an internal proxy; general tools, ours included, cannot see them.
Daily is sufficient for a date that moves once a year. More frequent checking matters mainly for confirming a renewal deployed correctly — CertPost checks hourly and Sematext looks for certificate changes every ten minutes.
Last updated August 4, 2026 · Written by Amit Gupta, founder of MonitoringDaddy
From $5 a month for 25 monitors, with certificate warning windows from 1 to 60 days.