---
kind: guide
zz: "0.9.0"
updated: 2026-10-14
state: live
rules: https://zriz.io/llms.txt
---
# Test the response time of an API

Add a time budget to a step of a zriz pipeline. The step fails when the API needs more milliseconds than your limit.

## The problem {#problem}

An API can return the right data and still be too slow. A test of the status code does not see this. Users see it first.

## The test {#test}

The example is a shop API. The health call must answer `200` in under 800 ms.

Start from a project that `zz init` made: the [quick start](https://zriz.io/docs.md) gives the commands. The resource `target` already has the action `check`.

`.zriz/resources/target.json`:

```json
{
  "type": "http",
  "description": "Your app under test",
  "base-url": "${env.TARGET_URL}",
  "headers": { "Content-Type": "application/json" },
  "actions": {
    "check": { "method": "GET", "path": "/api/health" }
  }
}
```

`.zriz/pipelines/health-is-fast.json`:

```json
{
  "description": "The health call answers in under 800 ms",
  "steps": [
    {
      "call": "target/check",
      "expect": [
        ["status", "==", 200],
        ["timing.target-ms", "<", 800]
      ]
    }
  ]
}
```

## Run it {#run}

```sh
zz run health-is-fast
```

```text
"status":"pass"
```

## What it proves {#proves}

- `timing.target-ms < 800`: the API answered fast enough. A slow reply fails the step. The reason is `assertion`: `timing.target-ms is 1130 and the pipeline expects 800`.
- `status == 200`: the reply is the normal one. A step with only a time budget passes on a fast `500`.

- The runner measures the number next to your API, in your network. A tool on your laptop shows a longer time, because it has the internet in it.
- The number is the time from the request to the end of the body. The time to open the connection is not in it.

> Note: One call is one sample. Set the limit to three times the usual time, or more.

## Next {#next}

- [Test a database query for speed](https://zriz.io/learn/test-database-query-speed.md)
- [Pipelines](https://zriz.io/docs/pipelines.md) gives each rule of the time budget, also for a repeat with `poll`.