> ## Documentation Index
> Fetch the complete documentation index at: https://docs.proxyjam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Checker

> Verify that a proxy actually works, and see what it reveals about you.

The **Checker** tab tests your profiles and reports five things about each one. Every field either shows a real answer or says it could not get one — it never fills a gap with a guess.

## The five fields

| Field        | What it means                                                                              |
| ------------ | ------------------------------------------------------------------------------------------ |
| Reachability | Whether the proxy accepted a connection at all. Always available; it needs no third party. |
| IP           | Your egress IP address, as seen from outside.                                              |
| Latency      | Round-trip time through the proxy.                                                         |
| Geo          | City, country, and ASN derived from the egress IP.                                         |
| WebRTC       | Whether local ICE candidates leak addresses outside the proxy.                             |
| DNS          | Whether lookups resolve outside the proxy. See [DNS-leak test](/extension/dns-leak).       |

Four of these need an outbound request to a third party, so they are **off by default**. Turn on the ones you want under [Settings → Network checks](/extension/settings#network-checks), where each one names the exact host it contacts.

<Note>
  A field you have not enabled shows `n/a`, not a blank or a zero. Hover it to see the reason.
</Note>

## Check versus Measure

Two buttons, two very different operations.

<CardGroup cols={2}>
  <Card title="Check" icon="circle-check">
    Tests the proxy without touching your current routing. Safe to run on any profile at any time, including all of them at once.
  </Card>

  <Card title="Measure" icon="gauge">
    Switches the browser onto that proxy, times a real request, then switches back. Accurate, but it briefly routes your traffic through the proxy being tested.
  </Card>
</CardGroup>

**Measure** exists because a proxy's true latency cannot be observed from outside it. The extension is explicit about the trade: the button's tooltip states that it briefly routes all traffic through the proxy and restores afterwards.

Only one measure or [health check](/extension/health-checks) can run at a time — both drive the browser's single proxy setting, and two at once would fight. A second one reports `busy` rather than queueing behind the first.

## Running the whole list

**Check all** runs every profile in sequence and fills the table as results arrive. Press it again to stop; results already collected stay on screen.

## Reading a result

* **Reachable, IP changed** — the proxy works and traffic is going through it.
* **Reachable, IP unchanged** — the proxy answered, but your egress address is the same as without it. Worth investigating.
* **Unreachable** — the proxy refused or timed out. If this profile is the active one, a [health check](/extension/health-checks) with failover would have switched you off it.
* **Field shows an error** — that specific lookup failed; hover for the reason. The other fields are still valid.