Grok AI Models: Ultimate Comparison Every Model Explained

Grok AI has evolved from a single chatbot into a broader family of AI models covering reasoning, coding, agentic workflows, multimodal understanding, image generation, video, and voice. The naming can be confusing because some Grok models are designed for general intelligence, while others are optimized for speed, coding, or specific media tasks.

The most important models in the current SpaceXAI API lineup include Grok 4.6, Grok 4.5, Grok 4.3, Grok 4.20 variants, and Grok Build 0.1, alongside separate Imagine and Voice model families. Several older models, including Grok 3 and Grok 4 Fast, have been retired from the API.

The simple version is:

• Grok 4.6: flagship model for coding, knowledge work, reasoning and agents.
• Grok 4.5: strong coding and agentic software-development model.
• Grok 4.3: fast general-purpose model with a 1-million-token context window.
• Grok 4.20: current high-performance family with 1-million-token context and reasoning/non-reasoning variants.
• Grok 4.20 Multi-Agent: designed for parallel-agent research workflows.
• Grok Build 0.1: specialized for agentic software and application-building workflows.
• Grok Imagine: image and video generation rather than a conventional text model.
• Grok Voice: speech-to-text, text-to-speech and real-time voice-agent capabilities.

The right model therefore depends less on its number and more on what you are trying to accomplish.

What Are Grok AI Models?

Grok AI models are large AI models developed by SpaceXAI for conversational AI, reasoning, coding, tool use, multimodal tasks and agentic workflows. The Grok family has progressed from the early Grok and Grok 1.5 generations to Grok 2, Grok 3, Grok 4 and the newer 4.x and 4.20 generations.

Unlike treating every Grok release as a completely separate chatbot, it is more useful to think of Grok as a model family. Different models can prioritize intelligence, speed, cost efficiency, coding, reasoning, or specialized tasks.

For developers, the distinction is especially important because model names, context windows, pricing and availability can change independently of the consumer-facing Grok experience.

Grok AI Models Comparison at a Glance

The following table focuses on the models and families that matter most in the current API ecosystem.

The specifications above reflect SpaceXAI’s current model documentation where available. Several older models have been retired from the API, so historical specifications should not be confused with models currently served.

Which Is the Best Grok AI Model?

For most demanding developer workloads, Grok 4.6 is the flagship choice, while Grok 4.3 and Grok 4.20 variants can make more sense when context size, speed, cost or specialized agent architecture matters more than using the flagship model.

Grok 4.6 has a 500,000-token context window and supports function calling, structured outputs and reasoning. Its current API price is $2 per million input tokens and $6 per million output tokens for short-context usage, with higher pricing for requests reaching the long-context tier.

However, “best” is workload-dependent.

A developer building a complex coding agent may prefer Grok 4.6. A high-volume application processing huge documents may find Grok 4.3 or a Grok 4.20 variant more attractive because those models provide a 1-million-token context window.

Grok 4.6 Explained

Released: August 12, 2026

Grok 4.6 is the current flagship generation highlighted by SpaceXAI for coding, agentic tasks and knowledge work.

SpaceXAI describes the model as being designed particularly for long-running agents and ambitious interactive and visual work. It is intended to maintain performance across multi-step tasks such as researching a subject, analyzing information, working through a codebase or turning an idea into an application or other work artifact.

Grok 4.6 Specifications:

• Model ID: grok-4.6
• Context window: 500,000 tokens
• Input: $2 per million tokens
• Cached input: $0.50 per million tokens
• Output: $6 per million tokens
• Modalities: Text and image
• Reasoning: Supported
• Function calling: Supported
• Structured outputs: Supported
• API regions: US East and US West

For long-context requests of at least 200,000 tokens, SpaceXAI’s published pricing is higher: $4 per million input tokens, $1 per million cached input tokens and $12 per million output tokens.

What Makes Grok 4.6 Different?

Grok 4.6 is not simply a larger-number upgrade. SpaceXAI says its training focused heavily on agentic reinforcement learning across areas including general coding, knowledge work, web development, kernel optimization and computer-aided design.

It also builds on Grok 4.5’s training approach, with additional training focused on reasoning and advanced technical concepts.

Who Should Use Grok 4.6?

Grok 4.6 is particularly suitable for:

• Complex software development
• Coding agents
• Technical research
• Multi-step knowledge work
• Long-running autonomous workflows
• Codebase analysis
• Application generation
• Engineering-oriented tasks

For a developer who wants one high-end Grok model rather than maintaining several specialized choices, Grok 4.6 is the obvious starting point.

Grok 4.5 Explained

Released: July 16, 2026

Grok 4.5 arrived as a model specifically focused on coding, agentic tasks and knowledge work. SpaceXAI describes it as an intelligent coding model trained using datasets covering coding, science, engineering and mathematics.

Its API profile includes:

• Model ID: grok-4.5
• Context window: 500,000 tokens
• Input: $2 per million tokens
• Cached input: $0.30 per million tokens
• Output: $6 per million tokens
• Function calling
• Structured outputs
• Reasoning

Grok 4.5 vs Grok 4.6

Grok 4.6 builds directly on Grok 4.5 but expands the emphasis toward long-running agents and broader interactive and visual work.

The two models have identical headline short-context token pricing, but Grok 4.6 is positioned as the newer flagship.

For new projects, Grok 4.6 generally makes more sense unless you have a specific reason to use 4.5.

Grok 4.3 Explained

Grok 4.3 occupies a different position from Grok 4.6.

It offers a 1-million-token context window, configurable reasoning levels and relatively low token pricing compared with Grok 4.6. SpaceXAI lists support for none, low, medium and high reasoning.

Grok 4.3 Specifications:

• Model ID: grok-4.3
• Context: 1 million tokens
• Input: $1.25 per million tokens
• Cached input: $0.20 per million tokens
• Output: $2.50 per million tokens
• Function calling
• Structured outputs
• Configurable reasoning

Long-context pricing increases to $2.50 per million input tokens and $5 per million output tokens for requests reaching the higher context tier.

Why Choose Grok 4.3?

Grok 4.3 is attractive when you need:

• Very large context
• Lower API costs
• Tool calling
• Configurable reasoning
• Enterprise workloads
• Large document processing
• General-purpose AI agents

It demonstrates an important point in the Grok lineup: a newer model is not automatically the best model for every workload.

Grok 4.20 Explained

The current SpaceXAI documentation also lists a Grok 4.20 family with a 1-million-token context window.

The reasoning version is listed as:

grok-4.20-0309-reasoning

It supports text and image inputs, function calling, structured outputs and reasoning. The documented price is $1.25 per million input tokens and $2.50 per million output tokens, with cached input priced at $0.20 per million tokens.

Grok 4.20 Non-Reasoning

The non-reasoning variant is:

grok-4.20-0309-non-reasoning

It retains the 1-million-token context window and the same headline input/output pricing.

The important distinction is that the model is intended to provide a lower-latency alternative when extensive reasoning is not necessary.

Grok 4.20 Reasoning vs Non-Reasoning

The key decision is therefore not simply “which number is higher?” It is whether your application benefits from spending additional computation on reasoning.

Grok 4.20 Multi-Agent

SpaceXAI also documents Grok 4.20 Multi-Agent, with the model ID:

grok-4.20-multi-agent-0309

This model is specifically described as enabling multiple agents to collaborate in parallel on deep research tasks. It has a 1-million-token context window and supports function calling, structured outputs and reasoning.

This is particularly interesting for workflows where one model response is not enough.

For example, a research system could divide a large task into multiple parallel jobs:

1. One agent researches the subject.
2. Another checks competing evidence.
3. Another analyzes technical documentation.
4. Another identifies contradictions.
5. A final process synthesizes the results.

That makes the model conceptually different from simply asking a conventional chatbot to “research this.”

Grok Build 0.1 Explained

Grok Build 0.1 is a specialized model for agentic software, engineering and workflow tasks.

Its documented model ID is grok-build-0.1, with aliases including grok-code-fast-1 and grok-code-fast. It has a 256,000-token context window and supports function calling, structured outputs and reasoning.

Current documented pricing is:

• Input: $1 per million tokens
• Cached input: $0.20 per million tokens
• Output: $2 per million tokens
• Context: 256K

The model makes the most sense when the goal is not simply answering programming questions but working through software-building workflows.

What Happened to Grok 4 Fast?

Grok 4 Fast was introduced in September 2025 as a cost-efficient reasoning model.

At launch, it offered a 2-million-token context window, reasoning and non-reasoning variants, and was designed to deliver high intelligence with substantially lower token consumption and cost.

However, this is an important example of why old Grok comparison articles can quickly become outdated.

SpaceXAI retired the following models from its API on May 15, 2026:

• grok-4-1-fast-reasoning
• grok-4-1-fast-non-reasoning
• grok-4-fast-reasoning
• grok-4-fast-non-reasoning
• grok-4-0709
• grok-code-fast-1
• grok-3
• grok-imagine-image-pro

Requests to these retired model slugs were configured to redirect to Grok 4.3.

That means articles claiming Grok 3 or Grok 4 Fast are current API choices are now outdated.

Grok 3 Explained

Grok 3 was a major step in the evolution of the Grok family.

SpaceXAI introduced Grok 3 as a model combining extensive pretraining knowledge with advanced reasoning. It was made available to X and Grok.com users in 2025, with higher limits and advanced capabilities such as Think and DeepSearch for premium users at the time.

Grok 3 helped establish reasoning as a central part of the Grok product strategy.

However, Grok 3 should now be considered a legacy model for API purposes because SpaceXAI retired it from the API in May 2026.

Grok 4 and Grok 4 Heavy Explained

Grok 4 launched in July 2025 and represented a major shift toward large-scale reinforcement learning and native tool use.

SpaceXAI introduced both Grok 4 and Grok 4 Heavy, with Heavy using parallel test-time computation to consider multiple hypotheses at once.

Grok 4 also brought native tool use and real-time search integration to the model family.

The original Grok 4 API offered a 256,000-token context window and multimodal understanding, along with search capabilities through xAI’s tooling ecosystem.

Today, however, developers should distinguish the historical Grok 4 release from the newer models currently documented by SpaceXAI.

Grok 4.1 Explained

Grok 4.1 launched in November 2025.

Rather than focusing exclusively on raw reasoning performance, SpaceXAI emphasized improvements in real-world usability, creative interaction, emotional understanding, collaboration and reduced hallucination rates.

The model was rolled out to Grok.com, X and mobile applications.

Grok 4.1 is important historically because it showed that model development was moving beyond benchmark scores toward:

• Better conversational behavior
• More coherent personality
• Improved instruction following
• Reduced factual errors
• Better real-world interaction

Its fast variants were later retired from the API as SpaceXAI consolidated the model lineup.

Early Grok Models: Grok, Grok 1.5 and Grok 2

The Grok family began well before the 4.x generation.

Grok 1.5

Grok 1.5 improved reasoning and introduced a 128,000-token context length, representing an important early expansion of the model’s ability to handle longer inputs.

Grok 1.5 Vision

Grok 1.5 Vision introduced multimodal capabilities, allowing the model to work with visual information as well as text.

Grok 2

Grok 2 and Grok 2 Mini were announced in August 2024. This established a clearer model hierarchy, with a larger general model and a smaller model designed around efficiency.

These generations are now mainly useful for understanding Grok’s development history rather than selecting a current API model.

Grok AI Models Timeline

The timeline reflects official SpaceXAI announcements and current documentation, while some models have since been retired from the API.

Grok Imagine Models Are Different

Not every Grok model is a text-generation model.

SpaceXAI now operates separate Imagine capabilities for image and video generation.

The Imagine API supports image and video generation and editing. The current API documentation lists grok-imagine-image-2.0 for image generation, while SpaceXAI has also released newer video generations.

In June 2026, SpaceXAI announced Grok Imagine Video 1.5, describing improvements in motion, physics, audio and speech synchronization.

This means users looking for “the best Grok model for images” should not automatically choose Grok 4.6. The text/reasoning models and Imagine models serve different purposes.

Grok Voice Models

Grok has also expanded into dedicated voice infrastructure.

SpaceXAI’s current API ecosystem includes:

• Speech-to-text
• Text-to-speech
• Real-time voice conversations
• Voice agents
• Custom voices

The Voice API is therefore another model family rather than simply another version number in the Grok text-model hierarchy.

For applications such as customer-service agents, voice assistants, interactive characters or real-time conversational systems, developers should evaluate the Voice API separately from Grok’s text models.

Grok AI Models vs Grok on X

One of the biggest sources of confusion is the difference between Grok as a consumer product and Grok models as developer APIs.

A user on Grok.com or X may see options such as Grok 4.6 without ever needing to understand the underlying API model ID.

Developers, on the other hand, select explicit models such as:

• grok-4.6
• grok-4.5
• grok-4.3
• grok-4.20
• grok-4.20-multi-agent
• grok-build-0.1

Consumer availability and API availability therefore should not be treated as identical.

SpaceXAI currently lists consumer plans including Free, SuperGrok and SuperGrok Plus. Its pricing page lists SuperGrok at $30/month and SuperGrok Plus at $100/month, with the higher tiers providing expanded access and usage.

Grok API Pricing Compared

For developers, token pricing is one of the biggest differences between the models.

These are SpaceXAI’s published API prices and can change. Long-context requests have separate pricing tiers, so the headline price should not be treated as the final cost for very large requests.

Which Grok Model Should You Use?

For general AI work

Grok 4.6 is the safest high-end choice if capability is the priority.

For coding

Start with Grok 4.6 or Grok 4.5.

Grok 4.5 was specifically positioned around coding and agentic software, while Grok 4.6 extends that foundation toward broader agentic and knowledge-work tasks.

For huge documents

Consider Grok 4.3 or Grok 4.20, both of which provide a 1-million-token context window in the current documentation.

For multi-agent research

Grok 4.20 Multi-Agent is the specialized option because it is explicitly designed for multiple agents working in parallel on deep research tasks.

For application-building workflows

Grok Build 0.1 is designed around agentic software, engineering and workflow tasks.

For image generation

Use the Grok Imagine family rather than treating Grok 4.6 as an image-generation model.

For voice applications

Use the Grok Voice API and its speech/voice models.

What Does a 1-Million-Token Context Window Actually Mean?

A context window determines how much information a model can process within a request and its surrounding conversation context.

A 1-million-token context window can be useful when working with:

• Large codebases
• Long research documents
• Multiple technical papers
• Large datasets
• Extensive documentation
• Long-running agent workflows

However, a larger context window does not automatically mean better reasoning.

For example, Grok 4.6 has a 500K context window but is positioned as a stronger flagship model for coding, agents and knowledge work. Grok 4.3 and the Grok 4.20 family offer 1M context windows but occupy different positions in the product lineup.

Context size and model intelligence are separate specifications.

Reasoning vs Non-Reasoning Grok Models

One of the most important distinctions in modern Grok models is whether the model spends additional computation reasoning through a problem.

A non-reasoning model can be preferable when you need:

• Fast responses
• High throughput
• Simple transformations
• Routine classification
• Straightforward extraction
• Lower latency

Reasoning models are more appropriate for:

• Complex mathematics
• Difficult coding
• Multi-step planning
• Research
• Logical analysis
• Agentic decision-making

Grok 4.3 supports configurable reasoning levels, while the Grok 4.20 family includes explicit reasoning and non-reasoning variants.

Are Older Grok Models Still Relevant?

Yes, but mainly for historical context or legacy systems.

The most important distinction is between historical importance and current recommendation.

Grok 3, Grok 4, Grok 4 Fast and Grok 4.1 were important stages in the development of the platform. But API availability changes over time.

For example, SpaceXAI retired Grok 3 and several Grok 4 Fast variants in May 2026.

Therefore, if you encounter an older article recommending Grok 3 as the current API model, check the official model documentation before building a new application around it.

Common Misconceptions About Grok Models

“Grok 4.6 must have the biggest context window.”

Not necessarily. Grok 4.3 and Grok 4.20 models in the current documentation offer 1-million-token context windows, compared with 500K for Grok 4.6.

“The newest model is always the cheapest.”

No. Grok 4.3 and Grok 4.20 variants have lower published short-context token prices than Grok 4.6.

“Grok 4.6 is the image model.”

No. SpaceXAI has separate Imagine models for image and video generation.

“Grok 3 is still a current API option.”

Not according to the current retirement documentation. Grok 3 was retired from the API in May 2026.

“Model number tells you everything.”

It does not.

A specialized 4.20 model can be a better fit than a flagship 4.6 model for a specific workload. Context size, reasoning mode, tool calling, price and specialization all matter.

What Is the Best Grok Model for Developers?

For most new development projects, Grok 4.6 is the strongest default choice when maximum capability is more important than cost.

But a practical selection strategy is better than simply choosing the newest model:

Choose Grok 4.6 for demanding coding, research and agentic work.

Choose Grok 4.5 when your workflow is heavily focused on coding and software engineering.

Choose Grok 4.3 when you need a 1M context window and lower token costs.

Choose Grok 4.20 when its 1M context, reasoning architecture and pricing better match your workload.

Choose Grok 4.20 Multi-Agent for parallel-agent research systems.

Choose Grok Build 0.1 for specialized application-building workflows.

The best model is the one that produces the required quality at an acceptable latency and cost.

Where Can You Use Grok Models?

Grok models are available through several environments.

The consumer Grok experience is available through Grok’s web and supported applications, while developers can access models through the SpaceXAI API.

Grok 4.6 has also expanded into third-party enterprise and developer platforms. SpaceXAI announced availability through Amazon Bedrock, Google Cloud’s Gemini Enterprise Agent Platform and Microsoft Foundry during August 2026.

This broader availability is significant for organizations that want to evaluate Grok alongside other AI models within an existing cloud infrastructure.

Future of Grok Models

The direction of the Grok ecosystem is increasingly clear: the emphasis is moving from standalone chatbots toward agentic AI systems.

Recent releases have progressively added:

• More capable reasoning
• Native tool calling
• Long-context processing
• Coding agents
• Multi-agent workflows
• Application building
• Image generation
• Video generation
• Voice agents
• Enterprise deployment
• Cloud-provider integrations

Grok 4.6’s focus on long-running agents and Grok 4.20’s multi-agent architecture are especially representative of this direction.

For users, this means future Grok comparisons will likely become less about “which chatbot writes the best answer?” and more about which model can complete an entire workflow reliably.

Final Verdict

Grok model is no longer a simple sequence where every larger number automatically replaces the previous model.

Grok 4.6 is the current flagship for demanding coding, knowledge work and agentic tasks. Grok 4.5 remains highly relevant for software engineering. Grok 4.3 offers a compelling combination of 1M context and lower pricing, while Grok 4.20 introduces additional reasoning, non-reasoning and multi-agent options for specialized workloads. Grok Build 0.1 focuses on software-building workflows, while Imagine and Voice represent separate media and voice branches of the ecosystem.

The biggest lesson is simple: don’t choose a Grok model solely by its version number. Compare context length, reasoning requirements, tool use, latency, pricing and the actual workload you need to solve.

As SpaceXAI continues to update and retire models, the official model catalog should remain the final authority for current API availability and pricing.

Frequently Asked Questions

1. What are the main Grok AI models?

The current SpaceXAI ecosystem includes Grok 4.6, Grok 4.5, Grok 4.3, Grok 4.20 variants and Grok Build 0.1 for text, reasoning, coding and agentic workloads. Separate Imagine and Voice families handle media and voice tasks.

2. Which Grok model is the most powerful?

Grok 4.6 is currently positioned by SpaceXAI as its flagship model for coding, agentic tasks and knowledge work. However, specialized Grok 4.20 variants can be preferable for particular workloads such as 1M-context processing or multi-agent research.

3. Is Grok 4.6 better than Grok 4.5?

Grok 4.6 is the newer flagship and builds on Grok 4.5 with a stronger focus on long-running agents, interactive work and broader knowledge tasks. Both have 500K context windows and the same headline short-context API input/output prices.

4. Which Grok model has the largest context window?

Among the currently documented text models covered here, Grok 4.3 and the Grok 4.20 family provide 1-million-token context windows. Grok 4.6 and Grok 4.5 provide 500K.

5. Is Grok 3 still available through the API?

Grok 3 was retired from the SpaceXAI API on May 15, 2026. Requests using its retired model slug were configured to redirect to Grok 4.3.

6. Which Grok model is best for coding?

Grok 4.6 is the strongest general choice for demanding coding and agentic software tasks, while Grok 4.5 is specifically positioned around coding and agentic software. Grok Build 0.1 is another specialized option for software-building workflows.

Also Read –

Grok 4.6 AI Guide: Everything About Its Features, Pricing, Benchmarks and Availability

Build with Grok API: Pricing, Free Credits, and Complete Tutorial

SuperGrok Pricing & Features: A Complete Guide (2026)

Grok vs ChatGPT: Real-Time Speed Meets Deep Reasoning

Grok AI Image Generator Playbook: Mastering Grok Imagine