OpenAI vs Stability AI: Token Pricing, Speed & Intelligence
Full comparison of OpenAI and Stability AI — live token pricing, latency, throughput, context window, strengths, weaknesses, and best use cases. Updated July 2026.
OpenAI
GPT-4o, o3, and the world's most widely-used AI API
OpenAI is the creator of the GPT model family and the ChatGPT product. Their API provides access to frontier models including GPT-4o, the o-series reasoning models, and the GPT-4.1 long-context family. Pricing is competitive for frontier-tier capability, with prompt caching available on most models.
Stability AI
Open-weight image generation with Stable Diffusion
Stability AI is the creator of Stable Diffusion, the most widely used open-weight image generation model. Its API offers Stable Diffusion 3.5 Large and Stable Image Ultra for high-quality image generation.
Key metrics
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Live token pricing
Strengths & weaknesses
OpenAI
Stability AI
Key differentiators
The most widely-integrated LLM API — virtually every AI framework and tool supports OpenAI natively.
Stable Diffusion models are open-weight and can be self-hosted, making them the most flexible option for teams that need full control over their image generation pipeline.
Frequently asked questions
OpenAI FAQs
How much does the OpenAI API cost?
GPT-4o costs $2.50/1M input tokens and $10/1M output tokens. GPT-4o-mini is $0.15/$0.60 per 1M tokens. Prompt caching cuts input costs by 50% on eligible requests.
What is the difference between GPT-4o and o3?
GPT-4o is a fast, multimodal model optimised for chat, vision, and coding. o3 is a reasoning model that uses chain-of-thought to solve complex problems — it is slower and more expensive but significantly more capable on math, science, and hard coding tasks.
Does OpenAI support prompt caching?
Yes. Prompt caching is available on GPT-4o, GPT-4.1, o3, and o4-mini. Cached input tokens are billed at 50% of the standard input price, making long-context and repeated-system-prompt workloads significantly cheaper.
Stability AI FAQs
What is Stable Diffusion?
Stable Diffusion is an open-weight text-to-image model developed by Stability AI. It can be run locally or accessed via the Stability AI API, and has spawned a large ecosystem of fine-tuned variants.
How does Stability AI compare to DALL-E 3?
DALL-E 3 generally produces more photorealistic and instruction-following images out of the box. Stable Diffusion offers more flexibility through open weights, fine-tuning, and self-hosting.
Provider resources
OpenAI — GPT-4o, o3, and the world's most widely-used AI API
OpenAI is the creator of the GPT model family and the ChatGPT product. Their API provides access to frontier models including GPT-4o, the o-series reasoning models, and the GPT-4.1 long-context family. Pricing is competitive for frontier-tier capability, with prompt caching available on most models.
The most widely-integrated LLM API — virtually every AI framework and tool supports OpenAI natively.
Stability AI — Open-weight image generation with Stable Diffusion
Stability AI is the creator of Stable Diffusion, the most widely used open-weight image generation model. Its API offers Stable Diffusion 3.5 Large and Stable Image Ultra for high-quality image generation.
Stable Diffusion models are open-weight and can be self-hosted, making them the most flexible option for teams that need full control over their image generation pipeline.
Key strengths compared
OpenAI
- ▸Largest ecosystem & third-party integrations
- ▸Best-in-class function calling & structured outputs
- ▸Prompt caching on all major models
Stability AI
- ▸Open-weight models available for self-hosting
- ▸Wide community and ecosystem
- ▸Competitive API pricing
Provider category context
OpenAI is a frontier lab, founded in 2015. Stability AI is a frontier lab, founded in 2020. 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 Stability AI are frontier labs with proprietary models. Choose based on benchmark performance for your specific task: OpenAI leads on largest ecosystem & third-party integrations, while Stability AI leads on open-weight models available for self-hosting. 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.