Load testing with Postman

Postman is one of the best-in-market tools for functional testing of APIs.


Load Impact provides CLI tools to convert your Postman tests to: 

Choose one of the tools depending on your needs and desired script language. 
  • LUA tests: cloud execution and result visualization through Load Impact. Scripts are written in LUA.
  • k6 tests: local execution and Insights visualization. Scripts are written in Javascript.

The following section describes the steps to convert your Postman configuration.

1 - As a Postman user, you organize your API tests into collections of requests. First, you have to export your Postman collections. 

2 - Install the Command Line Tool.



3 - Use the command line to convert the Postman collection:
postman-to-loadimpact path/my-collection.json -o path/my-collection.lua
     postman-to-k6 path/my-collection.json -o path/k6-script.js
4 - [Only LUA tests] Copy the content of the command output into a new or existing user scenario script.

5 - It’s time to validate your load script and tweak it some specific cases:

5.1  -  Assign Lua variable values.

The transformer will convert variables as:


But, you will have to assign values to the auto-generate variables at the top of the script.
local url = “YOUR_VALUE”
local username = “YOUR_VALUE”
local repository = “YOUR_VALUE”

5.2  -  
Replicate the behaviour defined in your Postman pre-request and response test.

This code will be inserted as a comment before and after the Lua request. 
tests["Body matches string"] = responseBody.has("OMG");
tests["Status code is 200"] = responseCode.code === 200;

You could easily replace the code to simulate this behaviour:

5.2.1 - LUA tests using the Load script API 

if response.status_code ~= 200 then 
  log.error("Status code is 200") 
   -- or
  result.custom_metric("Status code is 200", 1)
if not string.find(response.body, "OMG") then 
  log.error("Body matches string")
  -- or
  result.custom_metric("Body matches string", 1)

5.2.2 - k6 tests using the k6 API. 

check(res, {
  "status was 200": (r) => r.status == 200

6 - 
Once, the script has been validated, you can run your load tests.

Happy load testing!

If you have any suggestions, please, contact support or post a Github issue.

See also:

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