Mozilla formally opposes Google's proposed Prompt API for web-based AI interaction

Mozilla has officially registered a negative standards position against the Prompt API specification, marking a formal objection to the proposal following Google's announcement of an intent-to-prototype. This development highlights the ongoing friction between browser vendors regarding the integration of artificial intelligence capabilities into the open web.

The issue was opened on 28 April 2025 within Mozilla's standards-positions repository, where the organisation tracks its stance on various web standard proposals before they become widely adopted. By assigning a "position: negative" label to the specification, Mozilla indicates its current assessment that the feature may pose risks to privacy, security, or interoperability, although specific technical justifications have not yet been detailed in public records.

The Prompt API proposal was authored by @domenic and is hosted under the webmachinelearning organisation. Its primary design intent is to facilitate communication between web pages and AI models, potentially leveraging existing browser capabilities or introducing new interfaces. Despite the proposal's clear objective, the specification remains in very early stages, with the explainer URL currently listed as "No response" in the issue metadata.

Google, through its Blink engine, has published an intent-to-prototype for the feature, signalling that the company plans to implement the functionality in the Chrome browser. This procedural step in the Chromium project suggests that the feature is moving toward development, even as Mozilla voices its opposition. Consequently, the final outcome of the standardisation process remains uncertain, as a negative position from Mozilla does not guarantee the feature will be blocked but may hinder cross-browser compatibility.

At this stage, the specific technical details of the Prompt API remain unclear to the wider industry. While the proposal aims to bridge the gap between web applications and AI systems, the lack of comprehensive documentation and an unavailable MDN URL suggests the specification may still be undergoing significant refinement. Mozilla has not provided an explainer or a definitive URL for the specification at this time, leaving the precise scope of the API somewhat opaque.

For investors and institutions monitoring the digital infrastructure, this dispute underscores the complexities of regulating emerging technologies within the browser ecosystem. The divergence in approach between Google's rapid prototyping and Mozilla's cautious review process could lead to a fragmented web experience for users relying on different browsers to access AI-driven services.