Firefox 151 Released with Picture-in-Picture API and Backup Tools

🔑 Enhanced Key Takeaways

•The Document Picture-in-Picture API in Firefox 151 extends beyond traditional video-only Picture-in-Picture, allowing developers to display arbitrary HTML content in an always-on-top floating window, which enables more complex use cases such as custom video players with full controls or interactive video conferencing interfaces.
•Firefox 151 enhances its built-in VPN, initially rolled out in Firefox 149, by allowing users to select server locations from five countries: the United States, the United Kingdom, France, Canada, and Germany; this free browser-level VPN offers a monthly data limit of 50GB and operates as a proxy, distinct from the full-device Mozilla VPN.
•The integrated PDF merging functionality in Firefox 151 builds upon recent advancements in Firefox 150 and Nightly builds, which introduced comprehensive PDF editing capabilities including the ability to reorder, copy, paste, delete, and export individual pages directly within the browser's PDF viewer.
•Firefox 151 features a redesigned Settings section with improved navigation, centralizing previously disparate elements like 'Extensions and themes' and 'Firefox support' to offer a more streamlined and user-friendly customization experience.
•Furthering its commitment to privacy, Mozilla is also introducing a Global Privacy Control (GPC) feature in Firefox 120, which allows users to send a universal signal to websites indicating they do not wish for their data to be shared or sold, a mechanism increasingly supported by privacy laws in several US states.

📊 Competitor Analysis▸ Show

Feature / Aspect	Firefox 151	Google Chrome (2026)	Microsoft Edge (2026)
Market Share (Global)	2.23% - 4.17%	64.38% - 71.37%	4.6% - 13.7%
Document Picture-in-Picture API	Supported (arbitrary HTML content)	Supported (arbitrary HTML content)	Not explicitly mentioned as supported for arbitrary HTML, primarily video PiP.
Built-in VPN	Free, 50GB/month, browser-level, server location selection (5 countries)	No built-in VPN (relies on extensions)	No built-in VPN (relies on extensions)
PDF Editing (Merge/Reorder/Delete)	Integrated merging, reordering, copying, pasting, deleting, exporting pages	Basic viewing, highlighting, annotations, form filling; no native page deletion or reordering	Basic viewing, highlighting, annotations, form filling; no native page deletion or reordering
Privacy Focus	Strong, with Enhanced Tracking Protection, Total Cookie Protection, GPC, and built-in VPN	Less privacy-focused by default, collects anonymized browsing data for advertising	Improved privacy protections, blocks some trackers by default
Performance (Benchmarks)	Generally lags behind competitors	Often fastest or on par with Safari	Respectable third place, improved energy efficiency
Rendering Engine	Gecko	Blink (Chromium-based)	Blink (Chromium-based)
Cross-platform Local Backup	Enhanced cross-platform support for restoring local configuration backups	Typically relies on profile folder copy or sync features	Typically relies on profile folder copy or sync features

🛠️ Technical Deep Dive

The Document Picture-in-Picture API is accessed via the Window.documentPictureInPicture object and allows opening a new PiP window by calling documentPictureInPicture.requestWindow(options).
The requestWindow() method returns a Promise that resolves with the new window's Window object, and can accept options for width, height, disallowReturnToOpener (to hide the 'back to tab' button), and preferInitialWindowPlacement.
The Picture-in-Picture window created by this API floats on top of other windows, never outlives its opening window, cannot be navigated, and its position cannot be set by the website.
This API is available only in secure contexts (HTTPS).
Firefox's built-in VPN routes browser traffic through a proxy network (via Fastly) to mask the user's IP address, with sites seeing the proxy's IP instead.
The built-in VPN uses standard HTTPS encryption and is a browser-level protection, meaning it only covers traffic originating within Firefox, unlike full-device VPNs.

🔮 Future ImplicationsAI analysis grounded in cited sources

The expanded Document Picture-in-Picture API will foster new categories of web applications focused on multitasking and productivity.

By allowing arbitrary HTML content in an always-on-top window, developers can create more sophisticated, integrated experiences for video conferencing, custom media players, and other interactive tools, moving beyond simple video pop-outs.

Firefox's continued emphasis on built-in privacy tools, like the enhanced VPN and Global Privacy Control, will strengthen its position as a privacy-centric browser.

These features directly address growing user concerns about data tracking and online anonymity, potentially attracting users who prioritize privacy over the market dominance of Chromium-based browsers.

⏳ Timeline

1998

Mozilla project created from Netscape browser suite source code.

2002

First version of Phoenix (later renamed Firefox) released by Mozilla community members.

2003

Mozilla Foundation established as an independent non-profit organization.

2004-11

Firefox 1.0 officially launched, gaining rapid popularity.

2026-03

Firefox 149 introduced a free built-in VPN with a 50GB monthly data limit.

2026-04

Firefox 150 launched with advanced PDF editing features, including page reordering, copying, and deleting.

2026-05

Firefox 151 scheduled for release, introducing the Document Picture-in-Picture API and VPN server location selection.

Firefox 151 Released with Picture-in-Picture API and Backup Tools

⚡ 30-Second TL;DR

Key Points

🧠 Deep Insight

🔑 Enhanced Key Takeaways

🛠️ Technical Deep Dive

🔮 Future ImplicationsAI analysis grounded in cited sources

⏳ Timeline

📎 Sources (36)

👉Related Updates

Wispr Flow addresses user feedback with UI improvements

HBO Max introduces TikTok-style vertical video feed

PACA: Open-source tool for ancient fossil coordinate mapping