OpenAI · API

GPT-5.6 Sol API

GPT-5.6 Sol is the featured top-rate GPT-5.6 coding route, with 1M context, vision, and structured tool use for agent workflows.

Use 1M context with one OmniaKey API key.

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Model ID: gpt-5.6-sol
Context: 1M
Provider: OpenAI
Input · USD / 1M tokens: $0.35 USD; Official price $5 USD
Output · USD / 1M tokens: $2.2 USD; Official price $30 USD
Savings: 93%
Last verified: 2026-08-06

What this model is for

GPT-5.6 Sol is the featured and highest-priced route in OmniaKey's three-model GPT-5.6 family. It is intended for coding work where you want the family's top option before optimizing for per-token cost, including unfamiliar repositories, multi-step changes, and reviews that depend on evidence across many files.

The route lists a 1M context window, visual input, and structured tool use. Use the gpt-5.6-sol model ID with the OpenAI-compatible chat-completions endpoint, or select it in Codex, Cursor, Cline, and Aider when the client exposes custom model routing.

Choose Sol for the hardest GPT-5.6 coding and review tasks; use Terra or Luna when the lower listed token rate matters more than Sol's family position.

Best-fit coding workloads

Repository-scale analysis

Trace behavior across many files before planning a refactor or debugging a cross-package failure.

High-stakes code review

Inspect implementation, tests, and edge cases when missed behavior carries a meaningful cost.

Structured coding agents

Pair long context with search, test, and repository tools in multi-step agent workflows.

Technical specification

Catalog facts and integration details verified for this route.

Model ID: gpt-5.6-sol
Context: 1M
Inputs and tools: Vision · Tool use
API endpoint: /v1/chat/completions
Cache hit / 1M: $0.038 USD
Coding clients: Codex · Cursor · Cline · Aider

Limits to plan around

Sol has the highest listed input and output price in the GPT-5.6 family. Terra or Luna may be more economical for routine, high-volume iterations.
The 1M figure is a maximum context listing, not a guarantee that every client accepts or benefits from an unfiltered 1M-token request.
OpenAI-compatible clients differ in streaming and tool-call handling. Validate the exact SDK or agent version before relying on it in automation.

Compare nearby models

Compare workload fit and current listed token rates before choosing a route.

Model	Best for	Context	Input	Output
GPT-5.6 SolThis page gpt-5.6-sol	The featured GPT-5.6 route for the hardest coding, analysis, and review work in the family.	1M	$0.35 USD Official price $5 USD	$2.2 USD Official price $30 USD
GPT-5.6 Terra gpt-5.6-terra	A middle-rate GPT-5.6 option for regular development where Sol's top family position is unnecessary.	1M	$0.14 USD Official price $2 USD	$0.842 USD Official price $12 USD
GPT-5.6 Luna gpt-5.6-luna	Frequent, cost-sensitive iterations where the catalog's fast label and lowest 5.6 rate lead.	1M	$0.1 USD Official price $0.2 USD	$0.6 USD Official price $1.2 USD

SDK quickstarts

Use one base URL and model ID from cURL, Python, or TypeScript.

Streaming chat completion

curl https://api.omniakey.com/v1/chat/completions \
  -H "Authorization: Bearer $OMNIAKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.6-sol",
    "messages": [
      {"role": "user", "content": "Review this pull request"}
    ],
    "stream": true
  }'

Estimate token cost

Enter expected input and output tokens to compare current listed rates.

Input tokensOutput tokens

OmniaKey estimate: $0.079
Official-rate estimate: $1.10
Estimated savings: $1.021

Estimate covers input and output tokens only. Cache usage, retries, tools, and client-side token accounting can change the final charge.

Related coding guides

Deeper selection, setup, and troubleshooting guidance for this model family.

Claude Fable 5 vs GPT-5.6 Sol for Coding

Test Fable 5 first for the hardest long-horizon agent work; start with GPT-5.6 Sol when Codex, Responses, and the OpenAI tool stack define the workflow.

Read guide

Best GPT-5.6 Model for Codex

Start with Sol for difficult open-ended work, Terra for everyday coding, and Luna for clear repeatable tasks where speed and cost matter most.

Read guide

Claude Opus 5 vs GPT-5.6 Sol for Coding

Choose Opus 5 when ambiguous, long-horizon repository work rewards deeper investigation; choose GPT-5.6 Sol when you want the GPT-5.6 frontier model and its Responses-native tool stack.

Read guide

Sources and verification

Model facts and links were checked on 2026-08-06. Provider documentation remains the authority for upstream behavior.

Frequently asked questions

How much does GPT-5.6 Sol cost on OmniaKey?

OmniaKey charges $0.35 USD per 1M input tokens and $2.2 USD per 1M output tokens, in USD. Official prices are $5 USD and $30 USD; you save 93%.

What is the context window for GPT-5.6 Sol?

The listed context window is 1M. Actual usable limits can also depend on the client and upstream request format.

Should I choose GPT-5.6 Sol, Terra, or Luna for coding?

Start with Sol for the hardest or highest-risk work, Terra for general development at a middle listed rate, and Luna for frequent cost-sensitive iterations. Confirm the choice with representative tasks because price and family position do not replace workload testing.

Can GPT-5.6 Sol be used in Codex through OmniaKey?

Yes. The catalog lists Codex compatibility. Configure the OmniaKey base URL and API key, select gpt-5.6-sol, and use the linked compatibility kit to separate model-access, API, streaming, tool-call, and CLI issues.

Does GPT-5.6 Sol support streaming and function calls?

The route is listed with tool use, and this page includes OpenAI-compatible streaming and structured-tool examples. Exact behavior still depends on the client and request format, so test both paths before production automation.