OpenAI vs Together AI: Token Pricing, Speed & Intelligence
Full comparison of OpenAI and Together 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.
Together AI
Open-source model hosting with competitive inference pricing
Together AI specialises in hosting open-weight models including the full Llama family, Mixtral, and DeepSeek variants. They offer live pricing via their public API and support fine-tuning workflows. A popular choice for teams that want open-source flexibility without managing their own GPU infrastructure.
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Live token pricing
Strengths & weaknesses
OpenAI
Together AI
Key differentiators
The most widely-integrated LLM API — virtually every AI framework and tool supports OpenAI natively.
The broadest open-weight model catalog with fine-tuning support — ideal for teams that need model customisation without self-hosting.
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.
Together AI FAQs
What models does Together AI support?
Together AI hosts 100+ open-weight models including the full Llama 3.x family (8B, 70B, 405B), Mixtral, DeepSeek R1, Qwen, and many others. They also support custom fine-tuned model deployment.
How much does Together AI cost?
Llama 3.3 70B costs $0.88/1M tokens (input and output). Llama 3.1 405B is $3.50/1M tokens. Smaller models like Llama 3.2 11B Vision start at $0.18/1M tokens.
Does Together AI support fine-tuning?
Yes. Together AI offers supervised fine-tuning for Llama and other open-weight models. You can upload training data, run fine-tuning jobs, and deploy the resulting model via their inference API.
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.
Together AI — Open-source model hosting with competitive inference pricing
Together AI specialises in hosting open-weight models including the full Llama family, Mixtral, and DeepSeek variants. They offer live pricing via their public API and support fine-tuning workflows. A popular choice for teams that want open-source flexibility without managing their own GPU infrastructure.
The broadest open-weight model catalog with fine-tuning support — ideal for teams that need model customisation without self-hosting.
Key strengths compared
OpenAI
- ▸Largest ecosystem & third-party integrations
- ▸Best-in-class function calling & structured outputs
- ▸Prompt caching on all major models
Together AI
- ▸Largest selection of open-weight models
- ▸Fine-tuning support for custom model training
- ▸OpenAI-compatible API — easy migration
Provider category context
OpenAI is a frontier lab, founded in 2015. Together AI is a inference api, founded in 2022. OpenAI as a frontier lab trains and serves its own proprietary models. Together AI as an inference API provider hosts open-weight models — typically offering lower prices for equivalent capability tiers but without access to proprietary frontier models.
How to choose between them
Choose OpenAI if you need largest ecosystem & third-party integrations. Choose Together AI if you need largest selection of open-weight models. For high-volume production workloads, run a cost comparison using the token pricing table above with your actual prompt/completion token ratio — the cheapest provider depends heavily on your input-to-output token ratio.