Open source
8 votes
About ChatGPT
ChatGPT is OpenAI's assistant, reached through a web app, a desktop app and mobile apps. The free tier is listed at $0 per month, and everything above it is sold either as a subscription or, for developers, as an API key that bills per token at published API rates instead.
Three models are listed: GPT-5.6 Sol, GPT-5.6 Terra and GPT-5.6 Luna. Each carries a context window of about 1.05 million tokens and a maximum output of 128K tokens, so what separates them is the cost of running them rather than how much they can read at a time. The Plus allowances make that concrete. Counted per five hour window, Sol runs to roughly 10 to 100 messages, Terra to 20 to 170, and Luna to 215 to 1,720. Choosing a model is partly a decision about how many turns a working session needs.
ChatGPT Go is listed at $8 per month and Plus at $20 per month, with Pro starting from $100. ChatGPT Business is $25 per user per month billed monthly, or $20 per user per month on annual billing, and a Business Premium seat carries five times the usage allowance of a Business Standard seat. Enterprise and Edu are quoted through sales, drop fixed rate limits altogether and scale usage with credits instead. Codex is reachable from the web, a command line interface, an IDE extension and iOS.
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ChatGPT is also a host for third-party apps. An app is built on a Model Context Protocol server combined with skills and optional UI, and selected MCP tools can return UI resources back into the conversation. Anything bound for the public directory passes through a public review process first, and the developer guidelines are specific about what gets in. An app must supply a privacy policy before it can be installed. Its name cannot be a single dictionary word unless there is a genuine brand connection behind it. It may not collect payment card data, health information, government IDs or authentication credentials through its input schema. It must suit a general audience that includes users aged 13 to 17, and may not target children under 13. Apps that transact are limited to physical goods, with digital products, subscriptions, tokens and credits all prohibited.
On the compliance side, OpenAI holds SOC 2 Type 2 along with ISO 27001:2022, ISO 27017:2015, ISO 27018:2019, ISO 27701:2019 and ISO/IEC 42001:2023 attestations, and runs a responsible disclosure programme through Bugcrowd.
Key features
- Runs as a web app, a desktop app and mobile apps.
- Offers GPT-5.6 Sol, Terra and Luna, each with a context window of about 1.05 million tokens.
- Caps output at 128K tokens per response on the GPT-5.6 models.
- Allows roughly 10 to 100 Sol messages and 20 to 170 Terra messages per five hours on Plus.
- Allows roughly 215 to 1,720 Luna messages per five hour window on Plus.
- Reaches Codex from the web, a command line interface, an IDE extension and iOS.
- Gives the Pro plan 5 or 20 times the Codex usage of Plus.
- Carries 5 times the usage allowance on a Business Premium seat over Business Standard.
- Scales Enterprise and Edu usage with credits instead of fixed rate limits.
- Bills per token through an API key instead of a subscription.
- Builds apps from Model Context Protocol servers combined with skills and optional UI.
- Reviews apps publicly before listing them, and requires a privacy policy before install.
- Blocks apps from collecting card data, health information, government IDs or credentials.
- Limits in-app transactions to physical goods, not digital products, subscriptions or credits.
- Holds SOC 2 Type 2 and ISO 27001, 27017, 27018, 27701 and 42001 attestations.
- Runs a responsible disclosure programme through Bugcrowd.
What people use it for
Key facts
| Category | AI |
|---|---|
| Pricing | Freemium |
| Free tier | Yes |
| Upvotes | 8 |
| Listed | 22 August 2026 |
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