Elon Musk’s xAI appears ready to unveil its next major AI breakthrough. Multiple signs point to the upcoming launch of Grok 3.5, with code leaks, app modifications, and cryptic comments from Musk himself fueling speculation across the tech community.
The latest wave of evidence emerged when Twitter user @testingcatalog discovered a model reference labeled “grok-3-5-api-2k-p2” buried within Grok’s web build code.
This isn’t just a random string of characters it represents a significant development milestone that suggests xAI has been quietly preparing for launch behind the scenes.
Hints of Flexible Input, Model Selection, and First-Principles Reasoning
What makes this discovery particularly interesting is the mention of “flexible input” support alongside the model reference. This technical detail hints at potential improvements to how Grok 3.5 handles context or processes API requests, though the exact implications remain unclear until xAI provides official documentation.
Meanwhile, changes to Grok’s mobile experience are becoming visible to regular users. The iOS app now features a model selector integrated directly into the text input area, as spotted by @whylifeis4.
This user interface update suggests that multiple Grok models will soon be available simultaneously, allowing users to choose between different versions based on their specific needs.

These technical breadcrumbs gained additional weight when Musk himself entered the conversation. Responding to discussions comparing various AI models including Veo 3 and Claude 4, the xAI founder revealed that Grok 3.5 would emphasize “reasoning from first principles (truth).”
This philosophical approach indicates that the new model will prioritize deep technical accuracy and logical reasoning over generating quick, surface-level responses.
The focus on first-principles reasoning represents a notable strategic direction for xAI. Rather than simply competing on speed or conversational ability, Grok 3.5 appears designed to tackle complex problems by breaking them down to fundamental concepts and building solutions from the ground up. This approach could differentiate it significantly from other AI models currently available.
However, the AI community has learned to temper expectations when it comes to Grok releases. Similar speculation arose recently when other users spotted “Grok-3.5” references in the chatbot’s codebase, leading to widespread predictions about an imminent launch that never materialized. The pattern of excitement followed by waiting has become familiar territory for those following xAI’s development progress.
Grok 3.5: The Converging Evidence and xAI’s Strategic Silence
What sets this current round of speculation apart is the convergence of multiple indicators. Backend code changes, user interface modifications, and direct commentary from Musk create a more comprehensive picture than previous isolated discoveries.
The combination suggests that xAI may indeed be in the final stages of preparation rather than early development.
The timing could be strategic for xAI as competition intensifies across the AI landscape. Major players continue releasing updated models with improved capabilities, creating pressure for newer companies to demonstrate their technological advances.
A Grok 3.5 launch would help xAI maintain relevance and showcase its unique approach to artificial intelligence development.
Despite the mounting evidence, xAI maintains official silence about any upcoming releases. The company hasn’t confirmed development timelines, feature sets, or availability details for Grok 3.5. This cautious approach likely reflects lessons learned from previous AI launches where premature announcements led to inflated expectations.
The tech community continues monitoring xAI’s various platforms for additional clues about Grok 3.5’s capabilities and release schedule. Code repositories, app updates, and social media comments from company leadership remain primary sources of information while official announcements remain elusive.
Until xAI provides concrete confirmation, the AI community must balance excitement with healthy skepticism. The evidence certainly suggests significant developments happening behind the scenes, but translating technical preparations into a public launch involves numerous variables that could affect timing and execution.
For now, the question isn’t whether Grok 3.5 exists – the code references make that clear – but rather when xAI will feel confident enough to officially introduce their latest creation to the world.