How to tell if a Chinese supplier's CE certificate is real

Ask a factory whether a product is CE marked and the answer is always yes. A PDF arrives within the hour. It has a logo, a reference number and an official looking border.
It may well mean nothing, and not because anyone is lying.
CE is usually self declared
For most product categories, CE marking does not require an independent body to test anything. The manufacturer assesses the product against the applicable directives and signs a declaration saying it complies. That is the system working as designed.
So a "CE certificate" from a factory is often a document the factory produced about itself.
Higher risk categories are different. There, an independent notified body must be involved, and its four digit number appears next to the CE mark. If you see a CE mark with no number on a product that should have one, that is a problem.
The three documents, and which one matters
Declaration of Conformity. The manufacturer's signed statement. Should name the product, the model, the directives and standards applied, and the signatory. This is required. It is also self produced.
Test report. The actual testing, from a laboratory, with the lab's name, a report number, the standards tested against, the measurements and the results. This is the document with real information in it.
Certificate. Often issued by a commercial test house. Looks the most impressive and tells you the least on its own.
Ask for the test report. A factory with genuine testing sends it without fuss. A factory without one will send the certificate again, or tell you the report is confidential, which it is not.
How to check what you are sent
Does the model number match? The commonest failure. The report covers a model similar to yours, or a previous version. If the model on the report is not the model you are buying, the report does not apply to your goods.
Is the laboratory real? Search the lab name and the report number. Established labs are findable and many let you verify a report.
Is the standard the right one? An electrical safety standard is not an electromagnetic compatibility standard. Products like air coolers and heaters usually need both. One report rarely covers everything.
What is the date? Standards get revised. A report against a withdrawn version of a standard is not current compliance.
Is there a notified body number where one is needed? If the category requires one and there is no number, stop.
The UKCA question, which has changed
If you sell into Great Britain, you have probably read that you must move from CE to UKCA by some deadline. That advice is out of date.
The UK now recognises CE marking indefinitely for most product categories, including electronics, radio equipment, machinery, toys and PPE. UKCA remains available but is effectively optional for these goods. The cliff edge deadlines that caused so much noise have gone.
Two exceptions worth knowing. Construction products and medical devices sit outside the general recognition and have their own timelines. And Northern Ireland follows EU rules, so CE is required there and UKCA alone is not valid.
For the goods most importers deal with, a valid CE package is enough for the GB market.
Who carries the risk
This is the part that surprises people. Once you import a product and place it on the market, you take on obligations as the importer. If the compliance file behind the product is fiction, the regulator's conversation is with you, not with a factory in another jurisdiction.
That is why "they sent me a certificate" is not a defence, and why reading the test report is worth twenty minutes.
Every unit we ship comes with a test report from a named laboratory, with the report number quoted. We check the model number matches before the order is placed.