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10 ChatGPT pages in Developers.

Agents SDKThe OpenAI Agents SDK is an open-source library for Python (openai-agents) and TypeScript (@openai/agents) that runs agents with tools, handoffs and tracing inside your own app. OpenAI also offers the hosted Agents API (beta since Sep 10, 2026) and ChatKit, while Agent Builder shuts down Nov 30, 2026.
API Rate LimitsOpenAI API rate limits depend on your usage tier (Free, Build, Launch or Grow), which rises automatically as total credit purchases reach $5, $100 and $500. On the Build tier GPT-6 Astra allows 5,000 requests and 1,000,000 tokens a minute, and going over returns HTTP 429.
Apps SDKThe Apps SDK was OpenAI's 2025 toolkit for building apps inside ChatGPT on the Model Context Protocol (MCP). Since Jul 9, 2026 apps live inside plugins, and the Apps SDK documentation now opens OpenAI's Plugins docs, where you build an MCP server, optional UI and skills and submit them to the ChatGPT Directory.
Batch APIThe OpenAI Batch API runs up to 50,000 requests from one file within 24 hours at 50% off the normal price. Flex processing gives the same discount on ordinary calls that can be slow, Fast mode costs double for quicker answers, and prompt caching cuts the price of repeated prompt prefixes.
Fine-TuningOpenAI is winding down fine-tuning: the platform is closed to new users, new job creation was restricted on Jul 2, 2026, and existing customers lose job creation on Jan 6, 2027. Fine-tuned models keep serving until their base models are retired, and no GPT-6 model can be fine-tuned.
OpenAI APIThe OpenAI API lets programs call OpenAI's models (GPT-6 Astra, GPT-6.1 Sol, GPT-6.1 Terra, GPT-6 Luna, image, voice and transcription models) with an API key, billed per token. New projects use the Responses API through the official SDKs, with documentation at developers.openai.com.
OpenAI API PricingOpenAI API prices are per 1M tokens: GPT-6 Astra costs $10 input and $50 output, GPT-6.1 Sol $2 and $10, GPT-6.1 Terra $1 and $5, and GPT-6 Luna $0.10 and $0.50, as of Nov 6, 2026. Batch and Flex halve those prices, Fast doubles them.
Realtime APIThe OpenAI Realtime API streams speech in and speech out with low latency over WebRTC or WebSocket, using models such as gpt-realtime-2.1 and the full-duplex GPT-Live 1 ($0.05 a minute), as of Nov 6, 2026. It also handles live transcription and speech-to-speech translation.
Responses APIThe Responses API is OpenAI's recommended endpoint for new projects, combining model calls, built-in tools, structured outputs and conversation state in one request. Chat Completions is still supported, and the Assistants API it replaced shut down on Aug 26, 2026.
Whisper and Audio ModelsOpenAI's speech models turn audio into text and text into speech. As of Nov 6, 2026 the newest transcription model is GPT-Transcribe at about $0.0045 a minute, Whisper (whisper-1) and the GPT-4o transcribe models shut down Feb 26, 2027, and the text to speech models shut down Jan 6, 2027.