Results output

k6 provides two ways to look at test results:

• After the test runs, k6 sends a small summary to stdout.
• For granular analysis and time-series data, you can also stream live test data to an external output.

By default, when a test finishes, k6 provides an end-of-test summary report. This report aggregates the test results, with information about all groups, checks, and thresholds in the load test. It also gives basic, summary statistics about each metric (e.g. mean, median, p95, etc).

For fine-grained analysis, you can stream all the data that your test generates (e.g. all HTTP requests) to an external output. This output might be a structured file format, like CSV or JSON. But you could also stream to another program, like Datadog or Prometheus, or pipe results to our managed k6 cloud service. The "External outputs" section lists all supported built-in outputs.

You have much room to handle the data in the way that best fits your use case. You can customize the summary report. In addition to the built-in, you can also make custom metrics.

Standard output

When k6 sends the results to stdout, it shows the k6 logo and the following test information:

• Test details: general test information and load options.
• Progress bar: test status and how much time has passed.
• Test summary: the test results (after test completion).

You can completely customize the output and redirect it to a file. You can also save arbitrary files with machine-readable versions of the summary, like JSON, XML (e.g. JUnit, XUnit, etc.), or even nicely-formatted HTML reports meant for humans! For more details, see the handleSummary() docs.

Test details

execution: local
  script: path/to/script.js
  output: -

scenarios: (100.00%) 1 scenario, 50 max VUs, 5m30s max duration (incl. graceful stop):
        * default: Up to 50 looping VUs for 5m0s over 3 stages (gracefulRampDown: 30s, gracefulStop: 30s)

• execution: local shows the k6 execution mode (local or cloud).
• output: - is the output of the granular test results. By default, no output is used, only the aggregated end-of-test summary is shown.
• script: path/to/script.js shows the name of the script file that is being executed.
• scenarios: ... is a summary of the scenarios that will be executed this test run and some overview information:
• (100.00%) is the used execution segment
• 50 max VUs tells us up to how many VUs (virtual users) will be used across all scenarios.
• 5m30s max duration is the maximum time the script will take to run, including any graceful stop times.
• * default: ... describes the only scenario for this test run. In this case it's a scenario with a ramping VUs executor, specified via the stages shortcut option instead of using the scenarios long-form option.

End-of-test summary report

The test summary provides a general overview of test results. By default, the summary prints the following statuses to stdout:

• Aggregated values for the built-in metrics and custom metrics.
• Checks and thresholds.
• Groups and tags.

You can customize the summary shown to stdout, redirect it to a file or stderr, or build and export your own completely custom report (e.g. HTML, JSON, JUnit/XUnit XML, etc.) via the handleSummary() callback.

data_received..............: 148 MB 2.5 MB/s
data_sent..................: 1.0 MB 17 kB/s
http_req_blocked...........: avg=1.92ms   min=1µs      med=5µs      max=288.73ms p(90)=11µs     p(95)=17µs
http_req_connecting........: avg=1.01ms   min=0s       med=0s       max=166.44ms p(90)=0s       p(95)=0s
http_req_duration..........: avg=143.14ms min=112.87ms med=136.03ms max=1.18s    p(90)=164.2ms  p(95)=177.75ms
http_req_receiving.........: avg=5.53ms   min=49µs     med=2.11ms   max=1.01s    p(90)=9.25ms   p(95)=11.8ms
http_req_sending...........: avg=30.01µs  min=7µs      med=24µs     max=1.89ms   p(90)=48µs     p(95)=63µs
http_req_tls_handshaking...: avg=0s       min=0s       med=0s       max=0s       p(90)=0s       p(95)=0s
http_req_waiting...........: avg=137.57ms min=111.44ms med=132.59ms max=589.4ms  p(90)=159.95ms p(95)=169.41ms
http_reqs..................: 13491  224.848869/s
iteration_duration.........: avg=445.48ms min=413.05ms med=436.36ms max=1.48s    p(90)=464.94ms p(95)=479.66ms
iterations.................: 13410  223.498876/s
vus........................: 100    min=100 max=100
vus_max....................: 100    min=100 max=100

To learn more about the metrics k6 collects and reports, read the Metrics guide.

Trend metrics

Trend metrics collect trend statistics (min/max/avg/percentiles) for a series of values. On stdout, they are printed like this:

http_req_duration..........: avg=143.14ms min=112.87ms med=136.03ms max=1.18s    p(90)=164.2ms  p(95)=177.75ms

To change the stats reported for Trend metrics, you can use the summaryTrendStats option. You can also make k6 display time values with a fixed time unit (seconds, milliseconds or microseconds) via the summaryTimeUnit option. And, as mentioned above, you can completely customize the whole report via the handleSummary() callback.

$ k6 run --summary-trend-stats="min,avg,med,p(99),p(99.9),max,count" --summary-time-unit=ms  script.js

Export summary

To get your aggregated test results in a machine-readable format, you can export the end-of-test summary report to a JSON file. This helps with things like integration with dashboards, external alerts, etc.

We recommend the handleSummary() callback. It lets you customize the end-of-test summary and export the report data to any desired format (e.g. JSON, CSV, XML (JUnit/xUnit/etc.), HTML, TXT, etc.).

You can also use the --summary-export flag, though we now discourage using it).

External outputs

If you need more data than what is condensed in the end-of-test summary, you can integrate and visualize k6 metrics on other platforms.

To send granular results data to an external output, use the --out flag.

$ k6 run --out statsd script.js

The available built-in outputs are:

Multiple outputs

You can also send metrics simultaneously to several outputs. To do so, use the CLI --out flag multiple times.

$ k6 run \
--out json=test.json \
--out influxdb=http://localhost:8086/k6