As I’ve been working on API development and testing, I recently explored how to use Pre-request and Post-response scripts in Postman to automate and streamline my workflow. Here’s what I learned and how you can apply it too!
🔧 Pre-request Script: Dynamic Timestamping
I needed to send a request with a timestamp that was exactly 5 hours before the current time. Here’s the script I used:
let now = new Date();
let hour = 60 * 60 * 1000;
let multiplyer = 5;
let time_iso = new Date(now.getTime() - multiplyer * hour);
pm.environment.set("time_iso", time_iso.toISOString());
✅ This script calculates the time offset and stores it in an environment variable time_iso, which I then used in the request body like this:
{
"timestamp": "{{time_iso}}"
}
🔐 Authorization Setup
To authenticate the request, I used a Bearer Token in the Authorization tab:
- Type: Bearer Token
- Token:
{{auth_token}}(stored in environment variables)
Alternatively, you can add it manually in the Headers tab:
Key: Authorization
Value: Bearer {{auth_token}}
🧪 Post-response Script: Status Check and Token Extraction
After the request, I wanted to validate the response and extract a token for future use. Here’s the script I used:
pm.test("Status code is 200", function () {
pm.response.to.have.status(200);
});
let responseData = pm.response.json();
if (responseData.token) {
pm.environment.set("auth_token", responseData.token);
console.log("Token saved to environment:", responseData.token);
} else {
console.warn("Token not found in response");
}
✅ This script checks if the response was successful and saves the token to an environment variable for reuse.
💡 Final Thoughts
Using these scripts has made my API testing more dynamic and efficient. I can now automate timestamp generation, handle authentication seamlessly, and extract data from responses without manual effort.
If you're working with APIs in Postman, I highly recommend exploring these scripting features—they’re simple to implement and incredibly powerful!
