OpenAI API

GPT Series LLM API / Developer Platform O LLM Models & Providers

Basic Information

Product Description

The OpenAI API is the most widely used AI model API platform globally, offering access to the full range of models from GPT-4o to GPT-5.4. In 2026, the platform focuses on agent-based AI workflows, introducing development tools such as Responses API, Agents SDK, and AgentKit. Multimodality (documents, audio, images, video) has become a first-class citizen in the API. OpenAI also announced that the Assistants API will migrate to the more user-friendly Responses API in 2026.

Core Features/Characteristics

  • Model Matrix:
  • GPT-4o mini: $0.15/$0.60 per million tokens (most economical)
  • GPT-4o: $2.50/$10 (main model)
  • GPT-4.1: $2/$8
  • o3-mini: Small inference model (optimized for math/programming)
  • GPT-5.4: ~$10/$30 (latest flagship)
  • Responses API: Next-generation interface replacing the Assistants API
  • Agents SDK: Multi-step agent workflow development tool
  • AgentKit: Agent construction suite
  • Codex 5.2: Professional coding model
  • Realtime API: Real-time API supported by Python SDK
  • Usage API: Programmatic query for API usage and costs
  • Admin/Audit Log API: Organization management and audit logs
  • Multimodality: Full support for text, images, audio, and video

Business Model

  • Pay-as-you-go: Billed per input/output token
  • Tiered Pricing: Multiple price tiers from $0.15 to $30 per million tokens
  • Enterprise Edition: Custom solutions for ChatGPT Enterprise
  • Free Tier: Free API credits for new users
  • Volume Discounts: Price discounts for high-volume customers

Target Users

  • Global AI application developers
  • Enterprise-level AI integration projects
  • AI agent and automation developers
  • Startups and independent developers
  • Educational and research institutions

Competitive Advantages

  • Most widely used AI API—largest developer ecosystem globally
  • Richest model matrix, covering all price segments
  • GPT-4o mini offers exceptional value ($0.15 per million tokens input)
  • Mature agent development tools (Responses API, Agents SDK)
  • Comprehensive multimodality capabilities
  • Brand effect and first-mover advantage

Market Performance

  • Most globally used AI API
  • Nearly all AI frameworks and tools integrate OpenAI API by default
  • Enterprise clients cover most Fortune 500 companies
  • GPT series is the "benchmark" model for AI applications
  • Leads competitors in API revenue

Relationship with OpenClaw Ecosystem

The OpenAI API is one of the core APIs supported by OpenClaw. OpenClaw drives AI agents by calling GPT series models via the OpenAI API. The extremely low cost of GPT-4o mini is particularly suitable for daily agent tasks, while GPT-5.4 is ideal for complex reasoning scenarios. OpenAI's Responses API and Agents SDK are highly complementary to OpenClaw's agent framework. Since the OpenAI API is the most universal AI API format, OpenClaw's API compatibility layer also adheres to this standard.