OpenAI API review

The OpenAI API remains the most complete platform for building production features, and its price ladder now runs from very cheap to premium. GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens, GPT-6.1 Terra $1 and $5, GPT-6.1 Sol $2 and $10, and GPT-6 Astra $10 and $50. The models page lists a 1.05M-token context window and 128K maximum output across the GPT-6 family. Built-in tools include web search, file search and computer use, and the platform adds realtime voice, transcription and image models. Cost controls are good: the Batch API cuts input and output prices by 50%, flex processing trades speed for price, and you can set a monthly budget per project. Rate limits rise through Free, Build, Launch and Grow tiers as credit purchases pass $5, $100 and $500. Note that standard rates apply under 272K context, and there is no free API tier.

Who it is for

Product teams that want the widest set of built-in tools, agents and voice models from one vendor.

Price

Pay as you go; GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens.

GPT-6 Luna Our most efficient model for focused, high-volume tasks. Price Input: $0.10 / 1M tokens
Quoted from the vendor pricing page on November 7, 2026.

Key features

• GPT-6 family from Luna to Astra with up to 128K output tokens
• Built-in web search, file search and computer use tools
• Batch API at 50% off with a 24-hour window
• Flex processing for lower prices on lower-priority work
• Realtime voice and transcription models

Strengths and weaknesses

• Strength: The broadest tool and agent surface of any vendor on this list
• Strength: 1.05M-token context window across the GPT-6 models
• Strength: Monthly budget and per-project billing limits in the dashboard
• Weakness: Top model GPT-6 Astra costs $10 in and $50 out per 1M tokens
• Weakness: Listed prices apply to context lengths under 272K
• Weakness: No free tier for API calls; ChatGPT plans are billed separately

Key facts

• GPT-6 Luna: $0.10 in, $0.50 out per 1M tokens
• GPT-6.1 Sol: $2 in, $10 out per 1M tokens
• Context window: 1.05M tokens
• Usage tiers: Free, Build ($5), Launch ($100), Grow ($500 in credit purchases)

Where it ranks

OpenAI API is No. 2 in our Best LLM APIs verdict.