#gdpr

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UK GDPR — the retained version of the EU GDPR, now supplemented by the Data (Use and Access) Act 2025 — governs how organisations process personal data. Email signature management tools that route outbound email through third-party cloud infrastructure are data processors under Article 28, requiring a written Data Processing Agreement. Understanding which architectural model your signature tool uses determines what your compliance obligations are.

Further reading

Frequently asked questions

Does my email signature tool need to be listed as a data processor under UK GDPR?

If your email signature tool processes the personal data contained in your employees' outbound email — names, contact details, recipient addresses, email body content — then yes, the vendor is a data processor under UK GDPR Article 28. You must have a Data Processing Agreement in place and list them in your records of processing activities. Whether a tool processes this data depends on its architecture: server-side tools route email through the vendor's infrastructure and do process it; add-in tools that inject signatures at compose time may not.

What does UK GDPR Article 28 require for data processors?

Article 28 requires that any third party processing personal data on your behalf does so only under a written contract — a Data Processing Agreement — that specifies the subject matter, duration, nature, and purpose of the processing. The DPA must also confirm the processor's obligations around security measures, sub-processor restrictions, data subject rights assistance, and deletion or return of data after the contract ends.

Are server-side email signature tools a GDPR risk?

Server-side tools route your organisation's outbound email through the vendor's cloud infrastructure before delivery to the recipient. This means email content, attachments, and metadata leave your Microsoft or Google environment and pass through a third party. Under UK GDPR, this makes the vendor a data processor, requiring a DPA and due diligence on their security practices and sub-processor arrangements. The ICO's guidance on controllers and processors sets out what that due diligence should cover.