For the complete documentation index, see llms.txt. Markdown versions of documentation pages are available by appending .md to the page URL.
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Compare models
Frontier model for complex professional work
Reasoning
Speed
Input
Output
Reasoning tokens
Pricing
Per 1M tokens
Input
$5.00
Cached Input
$0.50
Output
$30.00
Context
Window
1,050,000
Max Output Tokens
128,000
Knowledge Cutoff
Feb 16, 2026
Endpoints
v1/chat/completions
v1/responses
v1/batch
Supported Features
Streaming
Function calling
Structured outputs
Image input
Rate Limits
TPM
Free
-
Tier 1
500,000
Tier 2
1,000,000
Tier 3
2,000,000
Tier 4
4,000,000
Tier 5
40,000,000
GPT-5.6 model that balances intelligence and cost
Reasoning
Speed
Input
Output
Reasoning tokens
Pricing
Per 1M tokens
Input
$2.00
Cached Input
$0.20
Output
$12.00
Context
Window
1,050,000
Max Output Tokens
128,000
Knowledge Cutoff
Feb 16, 2026
Endpoints
v1/chat/completions
v1/responses
v1/batch
Supported Features
Streaming
Function calling
Structured outputs
Image input
Rate Limits
TPM
Free
-
Tier 1
500,000
Tier 2
1,000,000
Tier 3
2,000,000
Tier 4
4,000,000
Tier 5
40,000,000