Which countries does this cover?
Any country, one country per file, with the country code on each number. Coverage of Viber itself is strongest where the app is popular.
Is Viber worth checking on a US list?
It depends on the audience. Viber is a stronger habit in parts of Eastern Europe, the Balkans and Asia than in the United States, so a +1 list may match mostly among people with ties to those regions. The check shows you the real share.
What does the activity check add over registration?
A registered number may belong to someone who installed Viber years ago. The activity check reports the last-seen information, so you can tell current users from old installs before you pay to reach them.
Can I run a list from several countries?
Not in one file. A phone file is refused unless at least 90% of its numbers share a country, so split it by country code first. That suits Viber well, since its popularity varies so much by market and one blended figure would hide it.
支払い方法は?
TRON(TRC20)または Ethereum(ERC20)の USDT、あるいは ETH で前払い残高をチャージすると、各チェックの料金がファイルのサイズに応じてそこから差し引かれます。サブスクリプションはなく、クレジットに有効期限はありません。