I am not sure what products are available in the OP's country, but if there is a choice; I would stay clear of any products that are not accompanied by authentic lab tests, for pesticides, PGRs, (plant growth regulators) mold etc.
If at all possible, I would stay away from any online vendors unless they can post their results from independent laboratories.
If you look for product reviews and find that most are reproductions from the vendor's own site; that is a dead giveaway that all is not as it appears.
CBD has become the snake oil of the century and there are tons of products out there that are not worth your money or potential health ramifications for your dog.
Actually most if not all of the CBD sellers on the internet are the manufacturers themselves. At least in the USA. All of the social media platforms prohibit CBD sales/advertising. Paypal will ban any seller for life who uses Paypal to make sales of CBD, . Credit card companies will not give merchant accounts to anyone selling CBD online. You cannot advertise CBD products anywhere on the web. Google ads, will not allow CBD and will ban you if they catch you. I know this because i tried to get into the business. I had to get a high risk merchant account for CBD, with transaction fees three times the normal. and could not find anywhere to advertise. This is why only the manufacturers are able to make it online. Online stores have no chance. There is somewhere between 6 and 10 American manufacturers selling direct to the public online. They all have inspection certificates for potency and purity on their web sites. Amazon carries brands no one has ever heard of before. So yes, ask for their inspection certificates, but there are plenty on the net that do have them. I just sold my entire inventory for 10% below my cost to liquidate it. It was the Pet Releaf brand, which was one of the first five in the USA.