OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4) vs xAI Grok 4
OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4) vs xAI Grok 4: side-by-side comparison of two foundation models (substrate reference) systems — architecture, taxonomy, license, pricing, MCP/A2A support, and direct edges.
Cost & capability
| OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4) | xAI Grok 4 | |
|---|---|---|
| Capability band | frontier | frontier |
| Capability composite | 95 | 88 |
| Cost tier | mid | premium |
| $/Mtok input | 1.25 | 3 |
| $/Mtok output | 10 | 15 |
| Use cases | Scoped Agentic, Code Generation Focused, Analytical Summarization, Memory Augmented Chat | Scoped Agentic, Code Generation Focused, Analytical Summarization, Memory Augmented Chat |
Where they differ (14)
Rows where both sides have data and the values disagree — the shortlist of dimensions that actually distinguish these two systems.
| OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4) | xAI Grok 4 | |
|---|---|---|
| Capability composite | 95 | 88 |
| Cost tier | mid | premium |
| $/Mtok input | 1.25 | 3 |
| $/Mtok output | 10 | 15 |
| Type | Frontier foundation model family (GPT-5 / GPT-4o / o3 / o4) | Frontier foundation model from xAI (Grok 4) |
| Created | 2018 (GPT-1); 2020-06 (GPT-3); 2023-03 (GPT-4); 2024-05 (GPT-4o); 2024-09 (o1); 2025-01 (o3); 2025-08 (GPT-5) | 2023-07 (xAI founded); 2023-11 (Grok 1); 2024-08 (Grok 2); 2025-02 (Grok 3); 2025-07 (Grok 4) |
| Latest release | GPT-6.1 Terra (2026-10-26; computer use) and GPT-6.1 Sol; earlier GPT-6 Sol / Luna / Instant in ChatGPT (2026-10-07) and API flagship GPT-6 Astra (announced 2026-09-03) | Grok 4.7 (2026-09-21) |
| License | proprietary (API only) | proprietary (Grok 4); older open weights: Grok-1 (Apache-2.0) and Grok 2 (Grok 2 Community License) |
| Pricing | API flagship GPT-6 Astra $10 input / $50 output per 1M tokens (Fast mode 2x price); ChatGPT Free / Go / Plus / Pro / Business / Enterprise plans | API: Grok 4.7 $2 in / $6 out per 1M (prompts ‹200k tokens; $4 / $12 above); consumer via X / SuperGrok subscriptions |
| Funding | $57.9B+ total raised; $500B valuation (2025 secondary tender); Microsoft $13B+ strategic investment | xAI merged into SpaceX (announced 2026-02-02, combined ~$1T); prior $20B Series E (2026-01, ~$230B valuation) |
| Deployment | Managed-only — OpenAI API + ChatGPT, also Microsoft Azure and AWS Bedrock (separate gpt-oss open-weight models exist) | Managed-only — xAI API, grok.com, X apps; also via Amazon Bedrock, Microsoft Foundry, GitHub Copilot (older Grok-1 / Grok 2 weights downloadable) |
| API surface | REST + SDK (Python, TS, Java, Go, .NET); Azure OpenAI variant; Realtime API (WebRTC) | REST + SDK (Python, TS); OpenAI-compatible |
| Optimised for | general-purpose reasoning, coding, multimodal, voice/real-time | real-time information (X firehose access); contrarian / less-filtered persona; benchmark frontier-tier reasoning |
| Anti-fit | weights closed; data residency limited (US/EU/Asia regions only); rate-limited without enterprise; no open-weights option; Sora video gated | X/Twitter integration is unique selling point but creates Musk-political-association risk; weights closed at Grok 4 tier; no on-prem; less polished tool-use than Claude/GPT |
At a glance
| OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4) | xAI Grok 4 | |
|---|---|---|
| Section | Foundation models (substrate reference) | Foundation models (substrate reference) |
| Tier | T1 | T1 |
| Type | Frontier foundation model family (GPT-5 / GPT-4o / o3 / o4) | Frontier foundation model from xAI (Grok 4) |
| Created | 2018 (GPT-1); 2020-06 (GPT-3); 2023-03 (GPT-4); 2024-05 (GPT-4o); 2024-09 (o1); 2025-01 (o3); 2025-08 (GPT-5) | 2023-07 (xAI founded); 2023-11 (Grok 1); 2024-08 (Grok 2); 2025-02 (Grok 3); 2025-07 (Grok 4) |
| Latest release | GPT-6.1 Terra (2026-10-26; computer use) and GPT-6.1 Sol; earlier GPT-6 Sol / Luna / Instant in ChatGPT (2026-10-07) and API flagship GPT-6 Astra (announced 2026-09-03) | Grok 4.7 (2026-09-21) |
| License | proprietary (API only) | proprietary (Grok 4); older open weights: Grok-1 (Apache-2.0) and Grok 2 (Grok 2 Community License) |
| GitHub | — | github.com/xai-org/grok-1 ~50k stars (older Grok 1 weights only) |
| Pricing | API flagship GPT-6 Astra $10 input / $50 output per 1M tokens (Fast mode 2x price); ChatGPT Free / Go / Plus / Pro / Business / Enterprise plans | API: Grok 4.7 $2 in / $6 out per 1M (prompts ‹200k tokens; $4 / $12 above); consumer via X / SuperGrok subscriptions |
| Funding | $57.9B+ total raised; $500B valuation (2025 secondary tender); Microsoft $13B+ strategic investment | xAI merged into SpaceX (announced 2026-02-02, combined ~$1T); prior $20B Series E (2026-01, ~$230B valuation) |
| Deployment | Managed-only — OpenAI API + ChatGPT, also Microsoft Azure and AWS Bedrock (separate gpt-oss open-weight models exist) | Managed-only — xAI API, grok.com, X apps; also via Amazon Bedrock, Microsoft Foundry, GitHub Copilot (older Grok-1 / Grok 2 weights downloadable) |
| API surface | REST + SDK (Python, TS, Java, Go, .NET); Azure OpenAI variant; Realtime API (WebRTC) | REST + SDK (Python, TS); OpenAI-compatible |
| Optimised for | general-purpose reasoning, coding, multimodal, voice/real-time | real-time information (X firehose access); contrarian / less-filtered persona; benchmark frontier-tier reasoning |
| Anti-fit | weights closed; data residency limited (US/EU/Asia regions only); rate-limited without enterprise; no open-weights option; Sora video gated | X/Twitter integration is unique selling point but creates Musk-political-association risk; weights closed at Grok 4 tier; no on-prem; less polished tool-use than Claude/GPT |
Pros & cons
OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4)
Pros: Most-deployed frontier LLM (800M+ MAU ChatGPT); full multimodal stack (vision + audio + image gen + video gen); largest ecosystem of fine-tunes / RAG / agent integrations; Azure distribution.
Cons: Closed weights; expensive at Pro/o3 tier; legal exposure (multiple ongoing NYT / Authors Guild lawsuits); Sora & advanced features behind waitlists; SWE-bench trails Claude Opus 4.5.
xAI Grok 4
Pros: Real-time X/Twitter data access (unique among frontier models); Colossus supercluster gives independent training capacity; ARC-AGI-2 leader (vendor-stated).
Cons: Owner Musk political controversy creates enterprise procurement headwind; closed weights at Grok 4; no on-prem; less mature ecosystem than Anthropic/OpenAI/Google.