OpenAI — Foundation Models Platform

Foundation ModelsLayer 4Usage-based

Founded 2015|San Francisco, California|1001-5000

What is OpenAI?

OpenAI is the creator of ChatGPT and the GPT series of large language models, having pioneered the commercial LLM API market. Founded in December 2015 by Sam Altman, Elon Musk, Greg Brockman, Ilya Sutskever, and others as a non-profit, it transitioned to a capped-profit model in 2019 and is currently restructuring as a for-profit public benefit corporation.

OpenAI's API platform provides access to text generation (GPT-4o, GPT-5, o-series reasoning models), image generation (DALL-E), speech-to-text (Whisper), text-to-speech, and embedding models. The platform supports fine-tuning, function calling, and the Responses API for agent-native workflows. The open-source Agents SDK and tools like code interpreter and web search enable developers to build sophisticated AI applications.

In February 2026, OpenAI closed a record $110 billion funding round from Amazon, Nvidia, and SoftBank, valuing the company at $840 billion post-money. The company employs approximately 3,500-7,200 people and is reportedly targeting a 2027 IPO at up to a $1 trillion valuation.

Key Features

✓GPT-4o and GPT-4 Turbo frontier models
✓Function calling and structured outputs
✓Fine-tuning API
✓DALL-E image generation
✓Whisper speech-to-text

Pros & Cons

Pros

+Broadest range of AI models under one API (text, reasoning, image, audio)
+Well-documented API with simple SDKs and minimal learning curve
+State-of-the-art model quality across GPT and o-series reasoning models
+Fastest path from idea to working prototype with agent-native APIs
+API inputs not used for model training by default

Cons

-High cost at scale, especially for output-heavy workloads
-Vendor lock-in to OpenAI ecosystem and tooling
-History of API deprecations creating migration risk
-Data privacy and transparency concerns for regulated industries

OpenAI Pricing

Free trial available

Free Tier$0

✓$100 monthly spending cap
✓Basic rate limits
✓Access to GPT-3.5 Turbo

Tier 1Pay-as-you-go

✓$5+ spend to qualify
✓$100 monthly cap
✓GPT-4o at $2.50/$10 per 1M tokens

Tier 2-4Pay-as-you-go

✓$50-$250+ spend to qualify
✓Up to $5,000 monthly cap
✓Higher rate limits

Tier 5Pay-as-you-go

✓$1,000+ spend to qualify
✓$200,000 monthly cap
✓Maximum rate limits

View official pricing page

Common Use Cases

Developers and enterprises building AI-powered applications across all industries

•General-purpose text generation and chat
•Code generation and debugging
•Content creation and summarization
•Multi-modal applications with vision and audio
•Enterprise knowledge assistants

Using OpenAI with Respan

Respan acts as a unified gateway for OpenAI API calls, providing real-time observability, cost tracking, and intelligent routing. Teams can monitor token usage, latency, and error rates across all OpenAI models while enabling automatic fallback to alternative providers when OpenAI experiences outages.