Hi Yair,
Thank you for reaching out. The
TrafficEstimatorService is used to generate forecasting metrics for proposed campaigns, ad groups, or keywords.
The
TargetingIdeaService helps to generate new keyword ideas to use in your account based on how existing ones performed. It can generate forecasting metrics for these new proposed keywords as well as show historical metrics for them.
There is some overlap in these services but they serve different purposes.
Regards,
Mitchell
Google Ads API Team

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