Hi Marwan,
Thanks for reaching out. From the screenshots your sent it shows you were using the HISTORICAL METRICS in the Google Ads UI. Instead, you are supposed to click on the FORECASTS tab to compare the keyword estimates between the Adwords API and the Google Ads UI.
Please let me know if you have any further questions.
Thanks and Regards,
Xiaoming, Google Ads API Team
Thanks Xiaoming for you reply
Hi Marwan,
There is no specific service from the Adwords API that corresponds to the HISTORICAL METRICS tab in the Google Ads UI. However, you could retrieve the Clicks, Conversions, Cost and other metrics by running the KEYWORDS_PERFORMANCE_REPORT in the Adwords API to have a better understanding of the keywords performance.
I hope this helps. Please let me know if you have any further concerns.
Thanks and Regards,
Xiaoming, Google Ads API Team
Hello again,
I have tried to use Forecast in Google ads UI as you mentioned however it doesn't get any data as you can see in the screenshot below. Also you have mentioned to use keywords performance but I still don't have campaign running so I can get the performance. so is there any way to retrieve historical data from api

Hi Marwan,
The screenshot shows you are still on the HISTORICAL METRICS tab. Could you click on the FORECASTS tab which is to the left of the NEGATIVE KEYWORDS? KEYWORDS_PERFORMANCE_REPORT is used to monitor your keywords performance for the existing campaigns and it could show you how well the existing keywords performed. For Google Ads API, you could use KeywordPlanService.GenerateHistoricalMetrics() to retrieve the Keyword Plan historical metrics as shown in the Google Ads UI HISTORICAL METRICS. However, you will not be able to achieve this by calling the Adwords API. You could refer to this article for more details on the historical metrics and forecasts.
Please let me know if you have any further concerns.
Thanks and Regards,
Xiaoming, Google Ads API Team
Sorry I have uploaded different screenshot

Hi Marwan,
In order for me to further investigate it, could you please let me know how you implement your code on retrieving the estimates of the proposed keywords and the steps you generated the FORECASTS on the UI. I see there are some discrepancies in the keywords you used for estimates between the API and UI. Please make sure you use the exact same keywords for estimates both in API and UI.
Thanks and Regards,
Xiaoming, Google Ads API Team