How can I restrict personal data in WP REST API responses?

Use filters like 'rest_prepare_user' or 'rest_prepare_post' to remove fields such as email, IP address, or custom meta. Alternatively, register custom endpoints that return only non-personal data. Always test your endpoints to see exactly what data is exposed.

How do I handle erasure requests through the REST API?

Create a custom endpoint that requires authentication and user ID verification. This endpoint should delete or anonymise personal data across your database. Follow WordPress core functions like wp_delete_user or wp_anonymize_data. Ensure you also remove data from backups and logs.

Do I need consent to expose user data via the API?

Consent is only one lawful basis. You may have a legitimate interest or contractual need. If you rely on consent, it must be explicit and users must be able to withdraw it easily. For third-party API access, use OAuth consent screens to inform users precisely.

What about third-party applications using my REST API?

You are responsible for how third parties process personal data if they act as your data processor. Ensure you have data processing agreements in place. Limit API access via scoped permissions and monitor usage. Inform users about third-party integrations in your privacy policy.

WP REST API and UK GDPR: A Practical Compliance Guide

16 August 2026

Ensure your WordPress REST API meets UK GDPR standards. Learn best practices for data protection, consent, and subject requests.

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Understanding UK GDPR and the WP REST API

The UK GDPR, enforced by the Information Commissioner's Office (ICO), applies to any organisation processing personal data of UK residents. WordPress REST API exposes user data, posts, and custom fields, which can include personal information. If your API endpoints return names, emails, IP addresses, or other identifiable data, you must ensure compliance. This involves understanding what data you expose, how it is accessed, and whether you have a lawful basis for processing. The WP REST API is not inherently compliant; it simply provides a transport layer. Your responsibility is to configure permissions, sanitise output, and respect user rights, just as you would for any other part of your website.

Key GDPR Considerations for REST API Endpoints

When building or consuming WP REST API endpoints, consider three central GDPR principles: data minimisation, purpose limitation, and security. By default, certain WordPress endpoints like /wp/v2/users reveal usernames and other metadata. This can lead to data leakage. You should register your own custom endpoints that return only the necessary fields, or modify existing ones using the 'rest_prepare_*' filters. Also, be mindful of embedded data in responses, e.g., author details within posts. Review each endpoint to ensure it does not expose personal data without a legitimate need. Document your processing activities, as required by UK GDPR, and include API operations in your data flow mapping.

Securing Personal Data in API Responses

Security is a cornerstone of GDPR. To secure personal data delivered via the WP REST API, enforce authentication and authorisation. For protected endpoints, use OAuth 2.0 or JWT authentication, and check user capabilities before exposing sensitive fields. Enable SSL/TLS to encrypt data in transit. Additionally, avoid logging sensitive request data. Consider rate limiting to reduce the risk of scraping. For public endpoints, ensure that personal data is removed or anonymised. For example, you might replace email addresses with hashes or hide full names behind pseudonyms. Always run regular security audits and update your WordPress core, plugins, and themes to patch known vulnerabilities that could lead to data breaches.

Handling Data Subject Requests via REST API

Under UK GDPR, users can request access, rectification, erasure, and portability of their personal data. The WP REST API can help streamline these requests. Build endpoints that allow users to retrieve a copy of their data in a machine-readable format (e.g., JSON) to satisfy data portability. For erasure, create a secure endpoint that triggers anonymisation or deletion of user data across your system. However, be cautious: you must verify the identity of the requester to prevent unauthorised access. Use authentication tokens and perhaps two-factor verification. Also, implement a process to respond within the statutory one-month timeframe. Document each request and your response to demonstrate compliance to the ICO if needed.

Best Practices for Consent and Authentication

Consent is one legal basis for processing personal data, but it is not always required for API interactions. If you rely on consent for data collection via API integrations, ensure it is freely given, specific, and unambiguous. For example, when a third-party app asks to connect to your WordPress site via the REST API, present a clear consent screen showing exactly what data will be accessed and for what purpose. Authentication mechanisms like OAuth 2.0 offen include consent prompts. In the UK, you also need to consider the Privacy and Electronic Communications Regulations (PECR) when using cookies or similar technologies for authentication. Implement strong password policies, rate limiting, and audit logs to demonstrate accountability.

FAQ

No. The WP REST API is just a tool. Compliance depends on how you configure it. By default, some endpoints expose personal data like usernames. You must modify responses, secure endpoints, and follow UK GDPR principles to ensure compliance.

UK GDPR WordPress compliance WP REST API data protection WordPress data privacy plugin

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