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OpenAI vs xAI: Token Pricing, Speed & Intelligence

Full comparison of OpenAI and xAI — live token pricing, latency, throughput, context window, strengths, weaknesses, and best use cases. Rates sourced from public APIs — verify before use.

OpenAI

GPT-6 Astra, GPT-5.6 Sol/Terra/Luna — plus image, voice, and realtime APIs

OpenAI's September 2026 API lineup spans GPT-6 Astra (flagship frontier), GPT-5.6 Sol (promotional), GPT-5.6 Terra (balanced), and GPT-5.6 Luna (everyday). Beyond text, the platform includes GPT-Image-2.5 (Sunburst and Flare), GPT-Live-1 voice, GPT-Realtime-2.1 for low-latency voice agents, and transcription/translation models. Batch API saves 50% on all models. Check the live table for current per-token rates.

CodingChatVisionReasoningAgentsVoiceImage generation
Proprietary models

xAI

Grok 4.6 — SpaceXAI with Imagine Image 2.0, Voice Transcribe 2.0, and 500K context

xAI (operating as SpaceXAI) builds the Grok model family. Grok 4.6 is the current flagship with a 500K token context window. The September 2026 platform includes Imagine Image 2.0, Imagine Video 1.5, Voice API (speech-to-speech, TTS, STT), and Grok Voice Transcribe 2.0. Available on Azure AI Foundry, Oracle OCI, and Google Cloud Vertex. Check x.ai/api for current rates.

Real-time dataReasoningVisionImage generationVideo generationVoice AIChat
Proprietary models

Key metric comparison

OpenAI
xAI
Cheapest input ($/1M)

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Cheapest output ($/1M)

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Peak throughput

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Best latency (TTFT)

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Intelligence score

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Context window

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Live token pricing

Strengths and weaknesses

OpenAI

Wide API surface: text, image, voice, realtime, transcription, translation, web search, code execution
GPT-6 Astra at the frontier; GPT-5.6 Sol at promotional pricing
Prompt caching on all major models (10% of input price)
Batch API: 50% off all models for async workloads
Wide ecosystem — virtually every AI framework supports OpenAI natively
No open-weight models — full vendor lock-in
GPT-6 Astra output pricing is among the highest for frontier tier — check live table
Rate limits can be restrictive on lower tiers

xAI

Grok 4.6: competitive frontier pricing — check live table for current rates
500K token context window
Real-time X/Twitter data and web search grounding
Imagine Image 2.0 and Imagine Video 1.5 for multimodal generation
Voice API: speech-to-speech, TTS, and STT under one key
Available on Azure AI Foundry, Oracle OCI, and Google Cloud Vertex
No open-weight models — full vendor lock-in
Smaller ecosystem and fewer integrations than OpenAI
Limited model selection compared to frontier competitors

Key differentiators

OpenAI

A broad AI API platform — GPT-6 Astra to GPT-5.6 Luna covering multiple capability tiers, plus native image, voice, realtime, and transcription APIs under one key.

xAI

Grok 4.6 combines frontier-tier intelligence with real-time X/Twitter grounding, a 500K context window, and a full multimodal platform (Imagine Image 2.0, Imagine Video 1.5, Voice API).

Frequently asked questions

OpenAI FAQs

What are the latest OpenAI models as of 2026?

OpenAI's current lineup includes GPT-6 Astra (flagship frontier), GPT-5.6 Sol (promotional), GPT-5.6 Terra (balanced), and GPT-5.6 Luna (everyday). The o-series reasoning models remain available for complex multi-step tasks. Check the live table or platform.openai.com/docs/pricing for current rates.

How much does the OpenAI API cost?

OpenAI uses tiered per-token pricing across its model lineup. The Batch API cuts all prices by 50% for async workloads, and prompt caching reduces input costs by 50% on eligible requests. Check platform.openai.com/docs/pricing for current rates.

Does OpenAI support prompt caching?

Yes. Prompt caching is available on GPT-6 Astra, GPT-5.6 Sol, and other major models. Cached input tokens are billed at 50% of the standard input price, making long-context and repeated-system-prompt workloads significantly cheaper.

xAI FAQs

What is Grok 4.6 and how much does it cost?

Grok 4.6 is xAI's current flagship model with a 500K token context window, vision, function calling, and real-time web and X/Twitter access. Check x.ai/api for current per-token rates.

What is the xAI Imagine API?

The Imagine API offers image and video generation via Imagine Image 2.0 and Imagine Video 1.5. Both are available under the same API key as Grok text models. Check x.ai/api for current rates.

What is the xAI Voice API?

The Voice API includes speech-to-speech, text-to-speech, and speech-to-text (REST and streaming). Grok Voice Transcribe 2.0 was released September 2026. Check x.ai/api for current rates.

Provider resources

OpenAI

Provider page
Website
PricingDocs

xAI

Provider page
Website
PricingDocs

OpenAI — GPT-6 Astra, GPT-5.6 Sol/Terra/Luna — plus image, voice, and realtime APIs

OpenAI's September 2026 API lineup spans GPT-6 Astra (flagship frontier), GPT-5.6 Sol (promotional), GPT-5.6 Terra (balanced), and GPT-5.6 Luna (everyday). Beyond text, the platform includes GPT-Image-2.5 (Sunburst and Flare), GPT-Live-1 voice, GPT-Realtime-2.1 for low-latency voice agents, and transcription/translation models. Batch API saves 50% on all models. Check the live table for current per-token rates.

A broad AI API platform — GPT-6 Astra to GPT-5.6 Luna covering multiple capability tiers, plus native image, voice, realtime, and transcription APIs under one key.

xAI — Grok 4.6 — SpaceXAI with Imagine Image 2.0, Voice Transcribe 2.0, and 500K context

xAI (operating as SpaceXAI) builds the Grok model family. Grok 4.6 is the current flagship with a 500K token context window. The September 2026 platform includes Imagine Image 2.0, Imagine Video 1.5, Voice API (speech-to-speech, TTS, STT), and Grok Voice Transcribe 2.0. Available on Azure AI Foundry, Oracle OCI, and Google Cloud Vertex. Check x.ai/api for current rates.

Grok 4.6 combines frontier-tier intelligence with real-time X/Twitter grounding, a 500K context window, and a full multimodal platform (Imagine Image 2.0, Imagine Video 1.5, Voice API).

Key strengths compared

OpenAI

  • Wide API surface: text, image, voice, realtime, transcription, translation, web search, code execution
  • GPT-6 Astra at the frontier; GPT-5.6 Sol at promotional pricing
  • Prompt caching on all major models (10% of input price)
  • No open-weight models — full vendor lock-in
  • GPT-6 Astra output pricing is among the highest for frontier tier — check live table

xAI

  • Grok 4.6: competitive frontier pricing — check live table for current rates
  • 500K token context window
  • Real-time X/Twitter data and web search grounding
  • No open-weight models — full vendor lock-in
  • Smaller ecosystem and fewer integrations than OpenAI

Key weaknesses compared

OpenAI

  • No open-weight models — full vendor lock-in
  • GPT-6 Astra output pricing is among the highest for frontier tier — check live table
  • Rate limits can be restrictive on lower tiers

xAI

  • No open-weight models — full vendor lock-in
  • Smaller ecosystem and fewer integrations than OpenAI
  • Limited model selection compared to frontier competitors

Provider category context

OpenAI is a frontier lab, founded in 2015. xAI is a frontier lab, founded in 2023. Both are frontier lab providers — the comparison is primarily about pricing, model selection, and feature differentiation within the same tier.

How to choose between them

Both OpenAI and xAI are frontier labs with proprietary models. Choose based on benchmark performance for your specific task: OpenAI leads on wide api surface: text, image, voice, realtime, transcription, translation, web search, code execution, while xAI leads on grok 4.6: competitive frontier pricing — check live table for current rates. For cost-sensitive workloads, compare the cheapest model tier from each provider in the pricing table above — the gap between efficient-tier models is often larger than between flagship models.