The Update That's Been Coming for Three Years
Google Chrome is finally completing its transition to Manifest V3 for browser extensions — and this time, it's not being delayed. Starting this week, Manifest V2 extensions including uBlock Origin will stop working in Chrome's stable channel.
uBlock Origin, the popular open-source ad blocker with over 30 million users, has been vocal about the limitations of Manifest V3. Its creator, Raymond Hill, has explicitly stated that MV3's declarativeNetRequest API is less powerful than the webRequest API it replaces, making it impossible to replicate uBlock Origin's full blocking capabilities.
What Changes for Developers
For developers who build or rely on extension-based tools, this isn't just a privacy story — it's a technical forcing function:
- Browser extension APIs are shrinking. The move from
webRequesttodeclarativeNetRequestmeans extensions can no longer inspect and modify network requests in real-time. Rules must be pre-declared, limiting dynamic blocking. - Firefox is watching. Mozilla has committed to supporting both MV2 and MV3, making Firefox a haven for power users. Firefox's extension ecosystem may see a surge as Chrome users migrate.
- Enterprise environments will feel it hardest. IT departments using Chrome with custom content blockers face re-engineering work or migration to enterprise-grade solutions.
The Security Angle Nobody's Talking About
Beyond ad blocking, Manifest V3 fundamentally changes how Chrome extensions interact with the browser. Security teams that relied on MV2's webRequest for DLP (data loss prevention) or threat monitoring in the browser will need to rebuild or replace those capabilities.
The irony: Google frames this as a security improvement — reducing the attack surface of browser extensions. But for enterprise security teams, the result is a net reduction in visibility and control.
What Builders Should Do Right Now
Chrome's Manifest V3 is a watershed moment. The web just got a little less private, and the browser extension platform just got a lot more constrained. Builders, take note.