Sanity's data storage is hosted on Google Cloud Platform in the EU.

Sanity's data storage is hosted entirely on Google Cloud Platform (GCP) infrastructure. While GCP is technically a third-party provider in the sense that it's not Sanity's own data centers, Sanity operates and manages all services on top of GCP's infrastructure - you're getting Sanity's platform built on Google's cloud.

Here's the breakdown of where your data lives:

Primary data storage (Content Lake): Your structured content is stored in GCP's data center in St. Ghislain, Belgium (europe-west1 region). Sanity uses Google Compute Engine, Google Container Engine clusters, and Google Cloud Storage for this.

Asset CDN: Images, videos, and files you upload are delivered through Google's global CDN network (cdn.sanity.io) with points of presence worldwide for fast delivery to your end users.

API CDN: For API responses and GROQ queries, Sanity operates a separate CDN system across multiple GCP regions including Europe, North America, South America, Asia, and Australia.

Other subprocessors: According to Sanity's official subprocessor list, there are a few additional third-party services used for specific features:

• Sentry.io (USA) - for error tracking and telemetry
• Temporal Cloud (Ireland) - for coordinating distributed workflows
• Plain (UK) - for customer support
• Amazon Web Services (USA, Germany) - specifically for the Sanity Functions feature

From a compliance perspective:

• Your content data is stored in the EU by default (Belgium), which helps with GDPR compliance
• Sanity benefits from GCP's extensive security certifications (ISO 27001, SOC 2, HIPAA, PCI DSS, etc.)
• Sanity itself maintains SOC 2 Type 2 certification

So to directly answer your question: The core storage is on Google Cloud Platform (a third party), but Sanity manages and operates all the services. The additional third-party subprocessors listed above are used for specific operational features, not for storing your primary content data.