Best Large Language Models for Replit

Gemini 4 Argon is a frontier AI model from Google DeepMind built to sustain deep reasoning across complex, long-running professional workflows. Google designed the model for demanding work spanning software engineering, finance, legal tasks, enterprise knowledge work, cybersecurity defense, and creative writing. Argon supports coding, reasoning, multimodality, and multi-step task execution, allowing it to work across workflows that require information gathering, analysis, tool use, and extended problem solving. Its output token limit has been increased from 64,000 to 1 million tokens, giving the model additional capacity for lengthy reasoning and generation within a single trajectory. On DeepSWE v1.1, Google reports a score of 77.9% for real-world long-horizon software engineering, while its AutomationBench score of 51.3% measures performance on end-to-end business workflows. Google also reports strong results on evaluations covering finance, legal work, visual analysis, and long-video understanding, including a 91.7% score on LVBench. For cybersecurity teams, Argon can autonomously discover, validate, and patch software vulnerabilities and achieved a reported 68% score on CWE-bench v1. Google is initially providing the model to selected cyber defenders through its Fairwind Program while strengthening safeguards before expanding access to developers, enterprises, and consumers. Argon is planned to launch at an introductory price of $2 per million input tokens and $10 per million output tokens, with cached input tokens receiving a 95% discount from the standard input price.

Claude Sonnet 5.5 is a general-purpose AI model from Anthropic built for everyday professional tasks, agentic coding, knowledge work, and fast iteration. It is the second model in the Claude 5.5 family and is intended to complement Claude Opus 5.5 by offering lower-cost performance on more clearly defined workloads. Anthropic reports that Sonnet 5.5 generates output more than 30% faster than Sonnet 5 and usually completes tasks with fewer tokens. Pricing remains $2 per million input tokens and $10 per million output tokens, with cache reads priced at $0.20 per million tokens. On Terminal-Bench 4.0, the model scores 70.6%, compared with 10.3% for Sonnet 5, while also posting sizable improvements on FrontierCode, CursorBench, and other coding benchmarks. Its knowledge-work results are also substantially stronger, including a GDPval-AA score of 1844 and an AA-Briefcase score of 1811, both close to Claude Opus 5.5. Anthropic says early testers found the model faster, more collaborative, more concise, and particularly strong at design-oriented work such as polished interfaces and presentation decks. The model supports adjustable effort levels so users can trade off speed and cost against more extended reasoning and checking. Claude Sonnet 5.5 is available through Claude apps, Claude Code, the Claude Platform, and major cloud providers including AWS, Google Cloud, and Microsoft Azure.

Claude Mythos 5.1 represents Anthropic's latest advancement in the Mythos-class of models, tailored for sophisticated applications in cybersecurity, biology, scientific investigation, programming, and extensive knowledge-oriented tasks. While it shares the same foundational architecture as Claude Fable 5.1, it is differentiated by unique safety measures: Fable 5.1 is widely accessible, whereas Mythos 5.1 is limited to select trusted access programs designed with specific safeguards for cybersecurity and life sciences research. This model establishes a new benchmark in performance for autonomous coding and showcases unparalleled cyber capabilities among all Anthropic models released thus far. In the realm of scientific research, Mythos 5.1 can effectively handle specialized tools and intricate workflows related to molecular design, computational biology, and various technical fields. During testing by Anthropic, it successfully engineered high-affinity protein binders for multiple targets, achieving its highest recorded hit rate to date. Additionally, it demonstrated proficiency in optimizing seven different open-source deep learning models focused on protein and genomics. By pushing the boundaries of what is possible, Mythos 5.1 is positioned to make significant contributions to future research and development endeavors.

Claude Fable 5.1 is a frontier AI model from Anthropic built for demanding coding, research, knowledge work, and autonomous multi-step workflows. It delivers higher performance than Claude Fable 5 across benchmarks covering scientific research, terminal-based coding, business automation, computer use, multidisciplinary reasoning, and agentic software development. The model is particularly suited to long-running tasks where it must investigate problems, use tools, maintain context, verify intermediate work, and continue operating with limited supervision. Early evaluations highlighted improvements in areas such as root-cause analysis, code review, browser automation, financial research, document drafting, slide creation, and complex engineering workflows. Fable 5.1 also introduces lower cache-read pricing, which Anthropic says can reduce costs by roughly 25% for typical workloads and considerably more for context-heavy agentic tasks. Enterprise customers can use new privacy-oriented safeguard options that are designed to support zero-data-retention-style deployments while still maintaining misuse protections. Cybersecurity safeguards have also been refined to intervene less often on legitimate defensive work while continuing to restrict higher-risk activities such as exploit generation. Anthropic offers the model through Claude Code, Claude Cowork, Claude.ai, the Claude API, and supported cloud platforms. Claude Fable 5.1 is intended for developers, researchers, enterprises, and professional teams that need strong reasoning and coding performance without relying on Anthropic’s most restricted-access model tier.

Claude Opus 5.5 is a frontier AI model from Anthropic built for coding, research, business analysis, computer use, and complex agentic workflows. The model is particularly suited to long-running software engineering tasks such as codebase migrations, audits, debugging, optimization, and large-scale refactoring. Anthropic also positions Opus 5.5 for professional knowledge work including financial analysis, legal workflows, research reports, spreadsheets, presentations, and business automation. Compared with Claude Opus 5, the model is designed to use fewer tokens, generate responses more quickly, and reduce typical workload costs. Its communication style has also been refined to make outputs clearer, easier to scan, and more consistent with user-defined writing requirements. Opus 5.5 includes stronger defenses against prompt injection and is less likely to take irreversible or out-of-bounds actions during autonomous tasks. Enterprise safety features include action classification, an auditable open-source sandbox, code review capabilities, preserved thinking protections, and configurable safeguards for sensitive domains. The model supports zero data retention and is available with additional verification programs for vetted life sciences and cybersecurity organizations. Claude Opus 5.5 is accessible through Anthropic’s applications and API as well as AWS, Google Cloud, and Microsoft Azure.

Claude Opus 5 is Anthropic’s new state-of-the-art Opus model for coding, knowledge work, automation, science, and everyday AI assistance. The model is designed to provide near-frontier intelligence at a lower cost than Claude Fable 5 while keeping the same base pricing as Opus 4.8. Claude Opus 5 performs strongly on software engineering benchmarks, business task automation, computer use, novel problem solving, visual generation, and scientific research tasks. Users can adjust effort settings to trade off intelligence, speed, and token usage depending on the task. The model is also better at verifying its work, iterating carefully, building test harnesses, debugging root causes, and solving multi-step engineering problems. Anthropic highlights improvements in life sciences, including structural biology, organic chemistry, bioinformatics, and protein-related tasks. Claude Opus 5 includes alignment and safety safeguards designed to support beneficial work while blocking higher-risk cybersecurity and biology misuse. It is available through Claude.ai, Claude Max, Claude Pro, Claude Code, Claude Cowork, and the Claude API under the model name claude-opus-5. By combining stronger reasoning, coding ability, scientific capability, configurable effort, Fast mode, and enterprise-ready deployment options, Claude Opus 5 gives users a powerful model for demanding daily work.

Gemini 3.6 Flash is Google’s workhorse Flash model for developers and enterprises building production AI agents at scale. The model is designed to deliver higher quality than Gemini 3.5 Flash while improving token efficiency, latency, and overall task cost. Google says Gemini 3.6 Flash uses 17% fewer output tokens than 3.5 Flash on the Artificial Analysis Index and can show even larger efficiency gains on certain software engineering benchmarks. It is priced lower than 3.5 Flash at $1.50 per 1 million input tokens and $7.50 per 1 million output tokens. Gemini 3.6 Flash improves performance in coding, ML research, computer use, knowledge work, document parsing, chart analysis, report drafting, and data-heavy workflows. The model also supports built-in computer use through the Gemini API and Gemini Enterprise, making it more useful for agentic systems that need to operate across digital environments. Google highlights customer use cases involving financial transcript analysis, code migrations, visual workflows, and interactive design tools. The model includes enhanced Frontier Safety safeguards for CBRN and cyber offense misuse while aiming to reduce unnecessary refusals for beneficial uses. By combining efficiency, stronger reasoning, multimodal ability, computer use, and enterprise availability, Gemini 3.6 Flash gives teams a practical model for scaling AI agents in production.

Gemini 3.7 Flash represents Google's most advanced model for coding and agents, exhibiting significant enhancements in software engineering, knowledge-intensive tasks, web design, and intricate business processes. It excels in debugging and resolving issues, showcasing greater accuracy in first-pass code creation and a refined ability to generate code that is ready for production. When applied to web development, this model produces more functional designs and fully-featured applications with fewer prompts, maintaining strong adherence to design principles derived from screenshots, images, or comprehensive design systems. In fields with high knowledge requirements, such as finance, law, and biosciences, it enhances reasoning capabilities, precision, and comprehension of complex documents. Additionally, Gemini 3.7 Flash demonstrates superior performance in automating real-world workflows and executing multimodal tasks, catering to a range of applications from interactive web experiences and data storytelling to robotics and the creation of dynamically generated 3D content. Overall, its versatility makes it a powerful tool for a variety of professional domains.

Claude Fable 5 is Anthropic’s most capable generally available AI model, built to tackle demanding tasks across software development, research, business analysis, scientific exploration, and enterprise productivity. The model demonstrates state-of-the-art performance in coding, reasoning, visual understanding, long-context processing, and autonomous task execution. Claude Fable 5 can analyze large codebases, interpret complex documents and datasets, generate detailed reports, and assist with advanced decision-making processes. Its enhanced memory capabilities allow it to remain effective during long-running workflows and multi-step projects. The model also delivers strong performance in image analysis, chart interpretation, scientific reasoning, and technical problem-solving. Anthropic has incorporated advanced safety classifiers that detect certain high-risk topics and automatically redirect those interactions to a more restricted model experience. These safeguards are designed to reduce misuse while still providing productive assistance for legitimate users. Claude Fable 5 is available through the Claude platform and API, enabling developers and organizations to integrate advanced AI capabilities into their applications and workflows. The platform is designed to help businesses improve productivity, accelerate innovation, and streamline complex knowledge work.

Gemini 3.5 Flash is Google’s high-performance multimodal AI model built to deliver frontier-level intelligence, fast execution speeds, and advanced agentic capabilities for coding, automation, and enterprise workflows. As the first release in the Gemini 3.5 series, the model is designed to help developers, businesses, and users execute complex long-horizon tasks through AI-powered reasoning, workflow orchestration, and intelligent automation. Gemini 3.5 Flash combines powerful coding performance, multimodal understanding, and real-time responsiveness while outperforming earlier Gemini models and competing frontier AI systems across several coding and reasoning benchmarks. The model is optimized for agentic workflows, allowing it to plan, execute, and manage multi-step tasks such as software development, infrastructure management, document preparation, and business process automation through the updated Antigravity harness. Gemini 3.5 Flash can also deploy collaborative subagents that work together under supervision to complete demanding workflows more efficiently and at lower operational cost. Beyond coding and automation, the platform generates richer graphics, dynamic web interfaces, interactive animations, and advanced multimodal experiences that support developers and enterprise users building AI-driven applications. Google has integrated Gemini 3.5 Flash across the Gemini app, AI Mode in Google Search, Google AI Studio, Android Studio, Gemini Enterprise Agent Platform, and enterprise AI services to expand access to advanced AI capabilities globally. The model also powers Gemini Spark, Google’s new personal AI agent designed to operate continuously and assist users with digital life management and automated task execution.

Gemini 3.5 Flash Cyber is a dedicated model designed specifically for cybersecurity, built upon Gemini 3.5 Flash, and refined to efficiently discover, validate, and resolve vulnerabilities at scale. Its primary objective is to support defensive security operations by enabling organizations to quickly pinpoint critical vulnerabilities and produce dependable patches before they can be exploited. The remarkable blend of performance and efficiency offered by Flash provides an excellent basis for code scanning, assessing security issues, confirming the authenticity of findings, and suggesting precise remediation strategies within extensive software environments. In the CodeMender framework, numerous Gemini 3.5 Flash Cyber agents collaborate seamlessly, merging their insights into a comprehensive report that enhances the system's ability to analyze vulnerabilities from various perspectives and elevate the overall quality of the findings. This collaborative agent framework ensures exceptional performance on CyberGym, which serves as a benchmark for assessing cybersecurity effectiveness, while also fostering continuous improvement in vulnerability management practices. Ultimately, the capabilities of Gemini 3.5 Flash Cyber not only streamline security workflows but also strengthen an organization's resilience against potential threats.

ChatGPT is a powerful AI-driven platform designed to help users work smarter by providing instant answers, creative ideas, and task automation. It supports a wide range of functions, including writing, editing, coding, research, and brainstorming. Users can interact with the platform through text or voice, making it accessible across different devices and workflows. ChatGPT can summarize meetings, analyze data, and generate insights to improve productivity and decision-making. It also offers creative support for tasks such as content creation, planning, and strategy development. A key feature is workspace agents, which allow users to automate entire workflows and repetitive tasks within their organization. These agents can run independently, integrate with tools, and handle actions like updating records, sending messages, or generating reports. Teams can build and share agents across their workspace to standardize processes and improve efficiency. Built-in controls ensure that automation remains secure and manageable with permissions and monitoring. ChatGPT helps reduce manual work while enabling teams to focus on higher-value activities. Overall, it enhances productivity by combining intelligent assistance with scalable automation.

Gemini 3 Pro is a next-generation AI model from Google designed to push the boundaries of reasoning, creativity, and code generation. With a 1-million-token context window and deep multimodal understanding, it processes text, images, and video with unprecedented accuracy and depth. Gemini 3 Pro is purpose-built for agentic coding, performing complex, multi-step programming tasks across files and frameworks—handling refactoring, debugging, and feature implementation autonomously. It integrates seamlessly with development tools like Google Antigravity, Gemini CLI, Android Studio, and third-party IDEs including Cursor and JetBrains. In visual reasoning, it leads benchmarks such as MMMU-Pro and WebDev Arena, demonstrating world-class proficiency in image and video comprehension. The model’s vibe coding capability enables developers to build entire applications using only natural language prompts, transforming high-level ideas into functional, interactive apps. Gemini 3 Pro also features advanced spatial reasoning, powering applications in robotics, XR, and autonomous navigation. With its structured outputs, grounding with Google Search, and client-side bash tool, Gemini 3 Pro enables developers to automate workflows and build intelligent systems faster than ever.

Gemini 3.8 Flash stands out as Google's most advanced model for Flash, offering substantial enhancements compared to version 3.7 in areas such as software engineering, agent-based tasks, and intricate multi-step reasoning within specialized fields. Designed for extended coding projects and autonomous agents, it adeptly addresses complex engineering challenges in a comprehensive manner, ensuring the reliability essential for critical enterprise autonomy in specialized knowledge areas. This model excels particularly in quantitative and professional disciplines that demand sophisticated analysis and reporting, as well as in multi-step reasoning tasks spanning STEM, humanities, and professional domains. The improvements it showcases arise from a fundamental design decision: Gemini 3.8 Flash intensifies its focus on challenging tasks by conducting additional reasoning steps and utilizing tools iteratively, thus optimizing its performance. When operating at higher effort levels, it may consume more tokens to achieve superior outcomes, while developers also have the option to adjust to lower effort levels for varied results. Overall, this flexibility allows for tailored use based on project needs and desired outcomes.

Gemini 3.5 Flash-Lite stands out as the quickest model within Google's Gemini 3.5 lineup, specifically engineered for tasks requiring low latency and for enhancing developer workflows that demand high throughput, including agentic search, document processing, coding, and extensive data analysis. It boasts an impressive output capacity of 350 tokens per second and marks a significant enhancement over earlier Flash-Lite iterations in terms of both quality and agentic capabilities. Developers have the flexibility to adjust the model's thinking level to suit the demands of the task at hand: minimal or low thinking allows for rapid processing of large volumes, while elevated thinking levels accommodate more intricate, multi-step workflows involving subagents. Furthermore, the model is equipped with built-in computational skills, enabling it to interact effectively with various digital environments across compatible platforms. Additionally, Gemini 3.5 Flash-Lite excels in coding, comprehending long contexts, and executing real-world tasks, consistently outperforming its predecessor, Gemini 3.1 Flash-Lite, in critical assessments and even exceeding the performance of Gemini 3 Flash on multiple benchmarks related to agentic functions and software engineering. This impressive performance highlights its potential to transform how developers approach complex workflows and data-intensive tasks.

Gemini 3 Flash is a next-generation AI model created to deliver powerful intelligence without sacrificing speed. Built on the Gemini 3 foundation, it offers advanced reasoning and multimodal capabilities with significantly lower latency. The model adapts its thinking depth based on task complexity, optimizing both performance and efficiency. Gemini 3 Flash is engineered for agentic workflows, iterative development, and real-time applications. Developers benefit from faster inference and strong coding performance across benchmarks. Enterprises can deploy it at scale through Vertex AI and Gemini Enterprise. Consumers experience faster, smarter assistance across the Gemini app and Search. Gemini 3 Flash makes high-performance AI practical for everyday use.

Gemini 3.1 Pro represents the next evolution of Google’s Gemini model family, delivering enhanced reasoning and core intelligence for demanding tasks. Designed for situations where nuanced thinking is required, it significantly improves performance across logic-heavy and unfamiliar problem domains. Its verified 77.1% score on ARC-AGI-2 highlights its ability to solve entirely new reasoning patterns, marking a major leap over Gemini 3 Pro. Beyond benchmarks, the model translates advanced reasoning into practical use cases such as visual explanations, structured data synthesis, and creative generation. One standout capability includes generating lightweight, scalable animated SVG graphics directly from text prompts, suitable for production-ready web use. Gemini 3.1 Pro is available in preview for developers through the Gemini API, Google AI Studio, Gemini CLI, Antigravity, and Android Studio. Enterprises can access it through Gemini Enterprise Agent Platform and Gemini Enterprise environments. Consumers benefit through the Gemini app and NotebookLM, with higher usage limits for Google AI Pro and Ultra subscribers. The release aims to validate improvements while expanding into more ambitious agentic workflows before general availability. Gemini 3.1 Pro positions itself as a smarter, more capable foundation for complex, real-world problem solving across industries.

Gemini 3.1 Flash-Lite represents Google’s newest addition to the Gemini 3 family, built specifically for speed and affordability at scale. Engineered for developers managing high-frequency workloads, the model balances performance and cost efficiency without sacrificing quality. It is competitively priced at $0.25 per million input tokens and $1.50 per million output tokens, making it accessible for large production deployments. Compared to Gemini 2.5 Flash, it delivers substantially faster responses, including a 2.5x improvement in time to first token and a 45% boost in output speed. Benchmark evaluations show strong results, with an Elo score of 1432 and leading scores in reasoning and multimodal understanding tests. The model rivals or surpasses similarly tiered competitors while even outperforming some previous-generation Gemini models. A key feature is its adjustable reasoning control, enabling developers to fine-tune how much computational “thinking” is applied to each request. This flexibility makes it ideal for both lightweight tasks like translation and more complex use cases such as dashboard generation or simulation design. Early enterprise adopters have praised its ability to follow instructions accurately while handling complex inputs efficiently. Gemini 3.1 Flash-Lite is currently rolling out in preview within Google AI Studio and Vertex AI for enterprise customers.

Gemini 3.8 Flash Cyber represents Google's most advanced cybersecurity model, offering top-tier performance in identifying vulnerabilities and automating patching processes with remarkable speed for rapid iteration. Tailored for trusted defenders, it is accessible via the Fairwind Program. On CyberGym, a recognized industry benchmark for detecting vulnerabilities, this model showcases exceptional autonomous vulnerability discovery, outperforming both Gemini 3.5 Flash Cyber and larger frontier models. Furthermore, Google assessed its effectiveness on an internal benchmark that spans complex codebases across 20 programming languages, achieving a success rate of over 70% in identifying various vulnerabilities. Unlike many models that focus on offensive strategies, Gemini 3.8 Flash Cyber emphasizes the importance of fixing vulnerabilities, providing defenders with advanced tools that enhance their ability to stay ahead of cyber attackers. This focus on proactive defense represents a crucial shift in the cybersecurity landscape, prioritizing the safeguarding of systems over mere exploitation capabilities.

Claude Fable 5.5 is an anticipated but currently unannounced model in Anthropic's Claude family, and Anthropic has not confirmed that a model with this name will be released. As of September 30, 2026, Claude Fable 5.1 remains the latest officially documented Fable model. Fable represents Anthropic's highest-end model tier for demanding reasoning and long-horizon agentic work, while the newer Opus 5.5 and Sonnet 5.5 occupy lower-cost positions in the Claude lineup. Anthropic's current documentation gives Fable 5.1 a 1-million-token context window and maximum output length of 128,000 tokens. It supports text and image inputs with text output and uses adaptive thinking that remains active throughout model operation. Fable 5.1 defaults to high reasoning effort and is listed as having a June 2026 reliable knowledge cutoff and training-data cutoff. API pricing is $10 per million input tokens and $50 per million output tokens, while prompt-cache reads cost $0.25 per million tokens and Batch API processing receives a 50% input and output discount. Anthropic's official documentation currently provides model identifiers for Fable 5.1 across the Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry, and Claude Platform on AWS. No equivalent model identifier, specifications, benchmark results, pricing, availability information, or release schedule has been published for Claude Fable 5.5.