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How we handle unreadable addresses (and keep your data safe)

A guide to our address correction process and our International Data Transfer Agreements.

At Postworks, our goal is to get your letters delivered as quickly as possible. However, in very rare circumstances, a letter might have an address that our machines simply can't read, usually because of a typo in the postcode or an incomplete address.

To ensure these items don't just get stuck, we have a secure process in place to manually correct them. Here is how that works and the high-level security measures protecting your data.

When does this happen?

This process is only triggered if an address on the front of an envelope is incorrectly addressed or machine-unreadable. If the address is correct and clear, it never goes through this step.

What information is shared?

To fix the problem, our supplier (Whistl) may share an image of the front of the envelope with their specialist partner, Straive, who has teams in Manila and Vietnam.

It is important to know:

  • Name and Address only: Only the image of the envelope front is shared.

  • No Contents: The contents of your letters are never seen, opened, or shared.

  • No Extra Data: No other account or customer data is included.

How we protect your privacy

We take international data transfers very seriously. This process is governed by a legally binding International Data Transfer Agreement (IDTA) that provides appropriate safeguards under UK GDPR.

Here is how your data is protected "under the hood":

  • Immediate Deletion: Images are only held for the exact amount of time needed to correct the address. Once the fix is made, the image is deleted.
  • No Onward Transfers: Our partners are strictly prohibited from transferring this data to anyone else.
  • Hardened Security: The teams correcting the addresses work on "hardened" computers with full encryption, antivirus, and data loss prevention software.
  • Zero-Trust Access: Access is restricted to specific, authorized people using secure, multi-factor authentication (MFA).Physical Security: USB ports and mass storage are disabled by policy to ensure no data can be copied or moved.
  • Regular Reviews: These security requirements are reviewed at least every two years to ensure they remain at the highest standard.

Why do we do this?

We do this for one reason: to ensure your mail actually reaches its destination instead of being returned to sender. By manually correcting a typo, we can get your post back into the delivery stream immediately.


We know that "international data transfer" can sound a bit technical, but we hope this clarifies how limited and secure this specific process is.

If you have deeper questions about our data processing or security standards, our team is always here to help. Drop us a line at support@postworks.co.uk or speak to your Account Manager.