OpenAI

platform active paid

The leading commercial LLM provider, offering GPT-4, GPT-4o, o1, and other models via API. OpenAI defined many standards in the LLM space—their API format is the de facto standard, and their models set capability benchmarks.

Implements

Concepts this tool claims to implement:

  • GPT-4, GPT-4o, GPT-4 Turbo, and earlier GPT-3.5 models. Leading capability on most benchmarks.

  • Pioneered function calling API (tools parameter). Parallel function calls, JSON mode, structured outputs.

  • Embedding primary

    text-embedding-3-small and text-embedding-3-large models. Industry standard embedding dimensions.

  • GPT-4V, GPT-4o with vision capabilities. Image input support in Chat Completions API.

  • Defined the /v1/chat/completions API format that became the industry standard. Messages with roles, streaming, tools.

Integration Surfaces

  • REST API
  • Python SDK
  • Node.js SDK
  • ChatGPT (consumer)
  • Assistants API

Details

Vendor
OpenAI
License
proprietary
Runs On
cloud
Used By
human, agent, system

Notes

OpenAI is the dominant LLM provider by usage and mindshare. Their API format has become the standard—most other providers offer compatible endpoints. The o1 "reasoning" models represent a new paradigm with extended thinking.