Firefox 156 opens PDFs 45% faster and now starts with your Mac

PDF files are where Firefox users most often reach for Chrome. A slow spinner on a 10MB report, a lag on the print dialog — small enough to dismiss, repetitive enough to change habits. Firefox 156 cuts PDF viewer startup time by 45% and reduces memory and CPU usage on large JPEG images, targeting the friction that accumulates across a workday without any single incident feeling dramatic enough to act on.

The improvement comes from a reworked rendering pipeline in PDF.js, Firefox’s built-in PDF viewer — the same viewer embedded by thousands of web developers in their own applications. Faster startup means quicker access to the first page of a document, not just the load bar disappearing sooner; the gain is most visible on complex files with embedded fonts and form fields.

The more notable behavioral change is quieter. Firefox 156 now offers automatic launch at macOS login, a feature that Chrome added years ago and that Safari has had since macOS turned app startup into part of its system framework. Browsers have historically resisted always-on footprints: startup items are a reputational concession to the users who count them carefully. Firefox was the last major non-Safari macOS browser without this option. Adding it signals a calculation that the users annoyed by its absence outnumber those who would resent its presence.

The decision also matters for Firefox’s wider ecosystem. Waterfox, LibreWolf, and Pale Moon — three forks of Mozilla’s engine with varying modifications for privacy, speed, and legacy hardware compatibility — inherit startup behavior improvements from the trunk. Firefox’s declining market share has run alongside growth in its fork community, a dynamic that makes improvements to the base browser serve a larger audience than the install numbers alone suggest.

For French, German, and Italian users, Firefox 156 also adds Wikipedia article suggestions to the address bar. Type a partial title and the browser surfaces the matching entry before completing the search query. The feature has been available in English since Firefox 93; it arrives in these three European markets three years later, where they account for the largest share of non-English Firefox usage.

None of this changes Firefox’s structural position. Its global desktop browser market share sits around 3%, a floor it has held since 2023 after a decade of decline from its 28% peak in 2013. On iOS and iPadOS, Firefox is legally required to use Apple’s WebKit rendering engine, which means its PDF performance improvements do not apply on iPhone or iPad. The 45% PDF gain exists in a browser that most users encounter only when Chrome fails to behave in the way they expect.

The MFSA 2026-90 security advisory accompanying version 156 patches four vulnerabilities rated high impact; anyone running Firefox 155 is exposed to them. Firefox 157 arrives in two weeks under the browser’s biweekly release cycle. The schedule for its market share recovery does not.

Tags: Mozilla, browser, Firefox, macOS, PDF, software update