A profile does not open until its proxy has answered
Before every launch Mosaic checks that the proxy answers and tunnels. If it does not, the launch stops and tells you which part failed.
Mosaic is a desktop app
Email yourself the link and open it on your computer.

Checked before every launch, step by step
Add a proxy
Paste it onto a profile, or save it to the Proxies library. Username and password authentication works on all three protocols.
Press Start
Mosaic connects through the proxy and opens a tunnel before the browser starts. Only then does the window open.
Read the reason
A refusal names what failed, whether the proxy did not answer, refused the login or would not tunnel, so you know what to fix.
The smaller things it does
Authentication through a local relay
Chrome cannot log in to a SOCKS5 proxy on its own. Mosaic runs a small relay on your computer that does the login, so authenticated SOCKS5 works.
WebRTC
With a proxy attached, the engine stops WebRTC from going around the proxy, so a page cannot learn your real address that way.
Works with
Paste a whole proxy list and deal it out across your profiles
Paste hundreds, assign them, export them, rotate them.
Matched to the exitTimezone, language and location come from where the proxy comes out
Timezone, language and location follow the proxy.
Exit reputationCheck an exit address against blocklists before an account sees it
Blocklists and network type before you trust an exit.
Checked before every launch is in every plan
Free holds 3 profiles and 10 profile creations, with the same engine as Pro. Pro is $49 a month for any number.
Mosaic is a desktop app
Email yourself the link and open it on your computer.