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

# Circuit breaker

> Giving a failing dependency room to recover

A breaker watches a failing dependency and stops calling it. Break the payments API and watch the circuit trip, then recover.

## What to watch

Right click the payments API and inject a crash. Once half the calls in a four second window fail, the breaker opens and the rest fail in microseconds instead of waiting out a timeout. After three seconds it closes and probes again.

## What it is made of

| Component       | Count |
| --------------- | ----: |
| Circuit breaker |     1 |
| Client          |     1 |
| Service         |     2 |

## Under load

Measured by running this design through the simulator at multiples of its own offered rate of 100 requests a second. Twenty seconds of simulated time, one fixed seed, so the same numbers come out every time.

<Note>This design holds 150 requests a second with 0% errors. At 200 it is losing 20% of them.</Note>

| Offered | Goodput |     p99 | Errors |
| ------: | ------: | ------: | -----: |
|     100 |     117 |  93.3ms |     0% |
|     150 |     140 | 336.3ms |     0% |
|     200 |     139 | 355.5ms |  20.4% |
|     250 |     121 | 344.3ms |    52% |
|     300 |      46 | 348.6ms |  82.3% |
|     400 |      11 |   354ms |  97.4% |
|     600 |      29 | 293.7ms |  95.3% |
|     800 |       7 | 307.3ms |  99.2% |

<Card title="Open this example" icon="play" href="https://breakscale.tech">
  Load **Circuit breaker** from the Examples menu and drag the traffic slider yourself.
</Card>