Configurable Containers — Arlo

Configurable Containers routes each site into the right Firefox container, from a single configuration you edit as text.

Firefox's container ecosystem does two things separately today: persistent, named containers you assign by hand, and disposable ones created automatically. Configurable Containers puts one config in charge of both.

What it does

• Domain to container mapping. The common case is one line — a bare domain opens in a container named after it. Add detail only when you want a curated name, several domains sharing one container, or a choice between containers.
• Temporary by default, permanent by choice. Anything no rule matches opens in a fresh throwaway. Long-lived containers are opt-in, one rule at a time.
• Single sign-on that keeps working. Identity providers stay in whichever container started the login, so "Sign in with Google / Microsoft / Okta" doesn't break the way it does when every hop gets a new container.
• Continuity without leakage. Grouped sites stay in the same throwaway as you move between them, while crossing to an unrelated site still spins up a clean one.
• A choice screen when you want one. A rule can offer several containers and let you pick, with an optional preselected default.
• Link shims handled. Known redirectors aren't isolated, and the tab closes itself if it strands you on the shim.
• Per-site cookie seeds and content scripts, applied inside the container the site was routed to.
• Reopen the current tab in another container with Ctrl+Shift+O.

How you configure it

Everything lives in one YAML file, edited in a full-tab text editor built into the add-on (about:addons → Configurable Containers → Preferences). There is no form-based settings UI — the config is the whole interface. Saving validates it and reloads the extension; an invalid config can't be saved.

The shipped default routes nothing into a named container. It only marks the handful of hosts where isolating would break something, and includes commented examples to start from.

Privacy

Configurable Containers collects and transmits nothing. Your configuration is stored locally in your browser and never leaves it.

Source code and full configuration reference: github.com/ArloL/configurable-containers