Mosaic for agencies and media buyers managing ad accounts

An agency's ad work runs on other people's accounts: each client's business portfolio, ad accounts, payment settings and two-factor codes. The platforms have proper tools for sharing access, and those come first. Mosaic is for the part those tools leave to you, which is the browser: where each client's sessions live, which exit they use, and whose codes are on screen.

Use the platform's agency tools first

Meta lets a business share its Pages and ad accounts with a partner, such as an agency, through its business portfolio in Meta Business Suite; the partner needs a business portfolio of its own (Meta Business Help Center, read 2 November 2026). Google Ads has manager accounts, which let one sign-in view and manage many client Google Ads accounts (Google Ads Help, read 2 November 2026).

Those are the right way to get access. Mosaic keeps the accounts you are entitled to work on apart; it does not change what a platform allows, and it is not for cloaking ads, getting around a platform's enforcement or running accounts a platform has closed.

How it works: Provider minting

Where a separate browser still helps

Partner access does not cover everything an agency touches. Clients hand over logins for tools that have no agency mode. Some clients want their accounts worked only from their own market. Media buyers keep separate business identities for separate clients, each with its own payment method and two-factor device. And one browser with every client's sessions in it is one wrong tab away from launching a campaign on the wrong account.

So each client gets a profile in Mosaic, or a project of profiles for a bigger client:

1. One profile per client account. The profile's cookies, history and saved logins belong to that client only.
2. Its own exit. Add your proxy seller as a provider; each profile mints its own session, so no two clients share an address. Pick the client's country and the profile's timezone and language follow the measured exit.
3. Its own two-factor codes. Each profile has a credential vault with TOTP codes. The companion inside the browser shows the logins and codes for the client whose window you are in, and nobody else's.
4. Its own downloads. Reports and invoices save into the profile's own folder, deleted with the profile when the contract ends.

Seeing ads from the client's market

A profile with an exit in the client's country loads pages and ads as a local visitor would, with a matching clock and language list. That is how an agency checks placements, landing pages and local versions of a site without flying to the market. The proxy is checked before every launch, and Mosaic will not open a profile behind a proxy that has not answered, so a check never silently comes from your own office address. How to check a proxy before you use it covers what to look at in an exit.

Automating the routine

On Pro, the local REST API can create, start and stop profiles, and starting one returns a CDP endpoint that Puppeteer or Playwright attach to. A reporting script can open each client's logged-in browser in turn without anyone copying cookies around. The MCP server gives an AI assistant the same abilities, for agencies that work that way.

Limits to know

Mosaic has no team seats. Profiles live on the computer that made them, so it suits a buyer or a small agency working from one machine. If five people need the same client accounts at the same time, use the platforms' own user roles for that, and keep Mosaic for the work on your desk. Local first explains why profiles stay on one computer.

Managing multiple accounts without getting them linked covers the full setup. The pricing page has the plans: Free covers 3 profiles, and Pro at $49 a month includes the API.