Where a Controller uses third party systems to process personal data, the responsibility for consent still lays with it. Controllers bear the onus of acquiring GDPR-standard consent (or indicating any other lawful basis for processing the data), demonstrate it to the regulator and ensure it can be withdrawn as easily as it was given. Therefore, selecting Processors who are themselves GDPR-compliant and can support the controller’s obligations is key.

If the third party has processing purposes that are separate from the Controller's purposes, then the third party is deemed a Controller under Article 28.10. Here, the third party must secure its own legal basis for processing, whether by consent or another legal basis.

The Controller may update its contracts to seek certainty that its Processors are adhering to the same GDPR standard and that any breach can be indemnified by the Processor. Meanwhile, if the Processor believes the Controller infringes GDPR, they have an obligation under Article 28 to inform the Controller and record the notification.