Welle is an alternative to the popular Apache Benchmarking tool (ab) that is used to benchmark HTTP servers. It can produce a batch of requests to a specified URL and measure the time to response for every request. At the end, it collects statistics about the average response time and quantity of failed requests.

To install this tool, use the following command:

cargo install welle

Using this tool is simple: set a URL to test with a number of requests you want to send to a server:

welle --num-requests 10000 http://localhost:8080

By default, the tool uses a single thread to send a request and wait for the response to send the next request. But you can split requests across more threads by setting a --concurrent-requests command-line parameter with the number of necessary threads.

When a measurement is finished, it will print a report similar to this:

Total Requests: 10000
Concurrency Count: 1
Total Completed Requests: 10000
Total Errored Requests: 0
Total 5XX Requests: 0

Total Time Taken: 6.170019816s
Avg Time Taken: 617.001µs
Total Time In Flight: 5.47647967s
Avg Time In Flight: 547.647µs

Percentage of the requests served within a certain time:
50%: 786.541µs
66%: 891.163µs
75%: 947.87µs
80%: 982.323µs
90%: 1.052751ms
95%: 1.107814ms
99%: 1.210104ms
100%: 2.676919ms

If you want to use a HTTP method other than GET, you can set it using the --method command-line parameter.