Testing OpenWeather APIs in Postman – Step-by-Step
✅ 1. Prerequisites
✅ Install Postman
✅ Sign up on https://openweathermap.org
✅ Generate your API key from:
👉 https://home.openweathermap.org/api_keys
🛠️ 2. Create a Postman Environment (Recommended)
Go to Environments -- Create new
Add variables:
base_url → https://api.openweathermap.org
api_key → your actual API key
city_name → e.g. London
lat → e.g. 51.51
lon → e.g. -0.13
This helps reuse variables across requests.
🌐 3. Basic Test: Current Weather by City Name
Method: GET
URL:
{{base_url}}/data/2.5/weather?q={{city_name}}&appid={{api_key}}&units=metric
🔍 Postman Tests:
javascript
pm.test("Status is 200 OK", function () {
pm.response.to.have.status(200);
});
pm.test("City name is correct", function () {
const data = pm.response.json();
pm.expect(data.name).to.eql(pm.variables.get("city_name"));
});
pm.test("Temperature is present", function () {
const data = pm.response.json();
pm.expect(data.main.temp).to.be.a('number');
});
🌐 4. Test: 5 Day / 3 Hour Forecast
Method: GET
URL:
{{base_url}}/data/2.5/forecast?q={{city_name}}&appid={{api_key}}&units=metric
✅ What to check:
Status code is 200
Forecast list contains at least 10 entries
Each entry has main.temp, weather[0].description
🌐 5. Test: One Call API (Current + Forecast + Alerts)
Method: GET
URL:
{{base_url}}/data/3.0/onecall?lat={{lat}}&lon={{lon}}&appid={{api_key}}&units=metric
🔍 Tests:
javascript
pm.test("Contains current weather", function () {
let res = pm.response.json();
pm.expect(res.current).to.have.property("temp");
});
pm.test("Contains daily forecast", function () {
let res = pm.response.json();
pm.expect(res.daily.length).to.be.above(1);
});
🌐 6. Test: Air Pollution API
Method: GET
URL:
{{base_url}}/data/2.5/air_pollution?lat={{lat}}&lon={{lon}}&appid={{api_key}}
✅ What to test:
Status is 200
Response includes PM2.5, PM10, and AQI values
❌ 7. Negative Test: Invalid City
Method: GET
URL:
{{base_url}}/data/2.5/weather?q=InvalidCityName&appid={{api_key}}
🔍 Test:
javascript
pm.test("City not found returns 404", () = {
pm.response.to.have.status(404);
let res = pm.response.json();
pm.expect(res.message).to.include("city not found");
});
🧪 8. Suggested Postman Collection Structure
📁 OpenWeather API Testing
📄 Get Current Weather (Positive)
📄 Get Forecast 5 Days
📄 Get One Call API
📄 Get Air Pollution
📄 Negative Tests
Add tests to each request
Use folders to separate types: Current, Forecast, Pollution, Errors
🧰 9. Exporting Collection & Automating with Newman
Export collection: File → Export → Collection v2.1
Run it via CLI with Newman:
newman run "OpenWeather API Testing.postman_collection.json" --env-var "api_key=your_actual_key"
🧠 10. QA Best Practices for API Testing
Validate status codes (200, 400, 404)
Check presence and correctness of key fields (temp, humidity, weather)
Test edge cases (e.g., cities with special characters, empty inputs)
Monitor API limits and error responses
Use Postman Monitors to run tests daily/hourly
📚 Official OpenWeather API Docs
👉 https://openweathermap.org/api
🏷️Hashtags
#OpenWeatherAPI, #Postman, #APITesting, #QATesting, #WeatherAPI, #RestAPI, #TestAutomation, #PostmanScripts, #Newman, #SDET, #AutomationEngineer, #WeatherForecastAPI, #APIValidation, #WeatherAutomation, #QACommunity