Free tools
These do not expire, they are not trials, and there is no upsell wall halfway through. Use them as often as you like. If you want the results watched and kept afterwards, that is what the paid product is for.
One domain, about ten seconds, everything below at once.
Everything at once. Registration, certificate, mail, subdomains and hosting, written in plain language with an inventory before the warnings.
Run a checkWho issued it, when it expires, which names it covers and whether the chain of trust behind it is complete.
Run a checkWhether your email can be impersonated, and whether the records that stop that are actually working. Answers in words, not policy strings.
Run a checkWhat is still resolving under your domain, including the staging site somebody left public and records pointing at services that are gone.
Run a checkPlain instructions for everything a check can find, written for someone who does not know what a CNAME is, with the technical version underneath.
Read the guidesWhy domains lapse, what breaks business email, and what actually happens in the thirty days after a domain expires.
Read the guidesTen lookups is the limit. Past it the whole record fails, with no bounce and nothing in any log, while still reading as correct. This counts yours and shows where each one goes.
Count the lookupsBuilds the record and tells you honestly which policy you should be publishing today. Starts at monitor only, because reject on an unmonitored domain is how businesses block their own invoices.
Build a recordAsks five public resolvers the same question. Where they disagree, one is still holding the old answer, and the TTL tells you exactly how long for. Nothing actually propagates.
Check the resolversAn incomplete chain works in your browser and fails for API clients, fresh devices and payment integrations. Almost impossible to reproduce from the machine you built the site on.
Check the chainWhat actually happens after the date passes, stage by stage, and the point past which nothing can be done at any price. The dates differ enormously by extension.
See the timelineWhy these are free
Several established tools will check a domain at no cost, and they do it well. Putting a wall around the same checks would be both pointless and slightly insulting, since anyone can get the same answers elsewhere in a minute.
What none of them do is remember. Every free checker, including these ones, tells you where things stand right now and then forgets you existed. Come back in a year and it starts from nothing.
So use these as much as you want. The paid product exists for the moment you need to say how long something has been true, not what is true today.
Most people find at least one thing they did not know was there.