K6 Result not the same with Postman

Hi, I have run a performance test on postman before but then I run the same api endpoint using k6 to test the performance again. But, Why do I get different performance result? The response time in Postman is lower than the response time in k6. Can someone explain to me what may cause this?

Hi @hidayah,

Although I’d generally say that you need to take into account that both tools are different in the way they generate traffic, it’s difficult to say something from just that little information.

What kind of test did you run (rps, total reqs, duration, etc)?
What was the difference between both results? Big?
Did you measure other stats? Like total amount of requests, peak of rps? Did you measure those from both the client and the server?

There’s lot of aspects that may make your tests results to vary from one execution to the next one, even with the same tool, so hard to say.

What I’d recommend, in case you really want to focus on difference in results between Postman and k6 is to build a reproducible scenario (like a web server with no external load nor external dependencies) and run the same amount of tests, for few times, and compare the mean results.

Thanks!

1 Like