Google’s Silent SERP Tweak Upends SEO Industry: &num=100 parameter vanishes, sparking data chaos, cost surges
September 20, 2025
In a move that has blindsided the $80 billion search engine optimization (SEO) industry, Google has quietly dismantled a decades-old URL parameter that allowed tools to pull 100 search results in a single query. The removal of the “&num=100” parameter, spotted rolling out around September 10, 2025, is forcing rank trackers, analytics platforms, and marketing teams to scramble as impressions plummet, costs balloon, and core workflows grind to a halt.
The change, which Google has neither announced nor explained publicly, effectively caps search engine results pages (SERPs) at 10 entries per load, the default for everyday users. Previously, appending “&num=100” to a Google search URL (e.g., google.com/search?q=example&num=100) delivered the top 100 organic rankings in one efficient hit, a hack long exploited by SEO pros for keyword research, competitor analysis, and performance monitoring.
Now, fetching the same dataset requires 10 separate paginated requests, using parameters like “&start=10” for page two, multiplying server strain and API expenses by a factor of 10. “This is an industry-wide issue that impacts all rank tracking tools,” Semrush, a leading SEO platform with over 10 million users, stated in an urgent advisory on September 15. The company has deployed “workarounds to minimize disruption,” but warned clients to brace for evolving data reliability.
A Cascade of Disruptions: From Tools to Trust
The fallout has been swift and seismic. Major platforms like Ahrefs, Moz, and AccuRanker reported temporary outages, with dashboards flashing errors, missing rankings, and incomplete SERP reports. DataForSEO, a key API provider for SEO vendors, confirmed the shift on September 16, noting that requests specifying “num=100” now return just 10 results, defaulting all endpoints to a depth of 10.
Even Google’s own Search Console (GSC), the free analytics hub for webmasters, has been upended. Since September 10, desktop impressions have cratered for thousands of sites, with average positions paradoxically improving as “bot-driven” views vanish. A bombshell analysis by technical SEO director Tyler Gargula, reviewing 319 properties, revealed that 87.7% of sites lost impressions, while 77% saw keyword visibility evaporate overnight.
SEO consultant Brodie Clark, whose blog post “Were We Wrong About ‘The Great Decoupling’ After All?” went viral in industry circles, ties the timing directly to the parameter’s demise. Last year, SEOs coined “The Great Decoupling” to describe impressions soaring without corresponding clicks, blaming AI Overviews and other SERP features. Clark argues the culprit was inflated bot traffic from tools hammering “&num=100” queries, artificially boosting GSC metrics by registering impressions users never saw. “This change offers an alternate explanation for at least part of that decoupling, especially on desktop where most rank tracking happens,” he wrote.
On X (formerly Twitter), the reaction has been a mix of panic and dark humor. “SEO tools are dead or the price of scraping will skyrocket,” quipped one practitioner, echoing a sentiment rippling through threads. Agency SEOTERIC posted: “Google’s removal… limits accessible search results, challenging SEO data collection and analysis,” urging clients to “innovate and [adopt] new strategies.” Another user, @akashsinghseo, warned: “Rank trackers and SEOs are seeing data disruption… Adapt your reporting & check with your platform vendors.”
Why Did Google Pull the Plug? Theories Abound
Google’s silence has fueled speculation. Industry watchers point to a broader crackdown on automated scraping, which the tech giant has long decried as a strain on its infrastructure. “Google trying to protect their search results from getting scraped,” SEO consultant Gagan Ghotra posted on X, aligning with reports from PPC Land that the parameter was a “barn door for bots.”
Others see it as a nudge toward Google’s ecosystem. By using third-party tools, the company may be steering users to official channels like GSC or its Custom Search JSON API; ironically, the latter charges per 1,000 queries and caps at 10 results anyway. “The message from Google is clear: This is our data,” wrote Veronika Höller in a Reflect Digital analysis.
This isn’t isolated. Microsoft’s Bing Search APIs were retired in August 2025, hiking replacement costs 40-483%. Combined, these shifts squeeze SEO vendors, who may pass hikes to users or limit features, potentially pricing out small-to-medium businesses (SMBs) that rely on tools for survival.
Logical Position, an SEO firm, highlighted the SMB squeeze: “Higher costs, less clarity, and new risks of misinterpreting performance.” Yet, they frame a silver lining: “Cleaner impression data means a more accurate view of real human behavior in search.”
The Road Ahead: Adaptation or Overhaul?
As of September 20, no rollback is in sight, and Google has dodged queries from outlets like Search Engine Roundtable. Tools are racing to adapt, Semrush promises “full transparency” on fixes, while experts like Clark predict a pivot to top-20 tracking or diversified data sources.
For SEOs, the lesson is stark: Over-reliance on Google’s “whims,” as one X post put it, is a vulnerability. “Time to diversify or innovate—before the next silent switch,” urged MindBees in a September 18 breakdown.
In an era of AI-driven search and fleeting algorithms, this unheralded tweak shows a harsh truth: The game of SEO isn’t just about outranking competitors, it’s about outlasting the gatekeeper. As impressions settle and costs recalibrate, the industry braces for a leaner, meaner reality. One where true visibility demands more than a clever parameter- it requires reinvention.