Yes. Any account with a verified email address, on any plan including the free Basic plan, can use the ads.txt validator, the sellers.json checker and the comparison tool over the API. They are paid for with tokens you buy in advance, and verifying your email address credits a free starting balance so you can build against the API before deciding anything.

The endpoints that manage the domains, records and collaboration groups in your account need the Ad Network plan, which also includes the three tools above with no tokens to buy. See the token packs and the API documentation.