Viber has built-in proxy support on mobile and desktop. Go to Settings > General (mobile) or Privacy & Security (desktop), toggle “Use proxy” on, pick SOCKS5 or similar, enter IP:port/username/password from your proxy.
For free proxies, sign up at Webshare (10 free SOCKS5) or Oxylabs (5 free), or grab live lists from ProxyScrape/freeproxy.world – test them first as they die quick.
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