Check the Body, Not Only the Status
Errors such as 401 invalid API key, 402 insufficient credits or 429 rate limited can come back with HTTP status 200, so read the response body before treating a call as successful.
gpt-6-1-sol
Automatically append previous messages to maintain multi-turn context. May increase token usage.
Function calling
Web Access
Reasoning effort
Stream Response
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README
Complete guide to using gpt-6-1-sol
GPT-6.1 Sol API: How It Compares with GPT-6 Astra and Luna
GPT-6.1 Sol is OpenAI's upgrade to GPT-6 Sol, positioned between GPT-6 Astra and GPT-6 Luna. OpenAI describes it as nearly matching Astra on agentic coding, computer use and professional work at a lower price than Astra, and it has a 1,050,000-token context window. On Kie.ai it is available alongside GPT-6 Astra and GPT-6 Luna.
GPT-6.1 Sol API Parameters on Kie.ai
| Parameter | Value |
|---|---|
| Model | gpt-6-1-sol (responses report the model as gpt-6.1-sol) |
| Endpoint | POST /codex/v1/responses, compatible with the OpenAI Responses API |
| Context window | 1,050,000 tokens |
| Maximum input | 922,000 tokens |
| Maximum output | 128,000 tokens |
| Input types | Text, images and files, mixed in one message |
| Reasoning effort | low, medium, high, xhigh or max; default medium |
| Tools | Web search or function calling, not both in one request |
| Streaming | On by default (server-sent events); set stream to false for a single JSON response |
| Pricing | Shown in the pricing card above |
GPT-6.1 Sol vs GPT-6 Astra vs GPT-6 Luna: Which One to Use
On OpenAI's own evaluations, GPT-6.1 Sol matches GPT-6 Astra on DeepSWE v1.1 and comes within 2.1 points of Astra on OSWorld 2.0 at maximum reasoning effort, while Astra scored above GPT-6.1 Sol on Terminal-Bench Science 0.1, at 68.1%. Independent leaderboards also put the two close: Artificial Analysis gives Astra 53 and Sol 52 on its Intelligence Index, and LMArena's text leaderboard gives Sol 1484 and Astra 1475 with overlapping ranges (as of October 2026). GPT-6 Luna scores 38 on the same Artificial Analysis index. A practical default is Sol for coding, computer-use and document work, with Astra for the hardest research tasks, which is where OpenAI recommends Astra. On Kie.ai, Sol costs less than Astra; each model's pricing card has the details.
| GPT-6.1 Sol | GPT-6 Astra | GPT-6 Luna | |
|---|---|---|---|
| How OpenAI positions it | Nearly matches Astra on agentic coding, computer use and professional work | Its best model across the board, for when you want the best results | A faster, more affordable GPT-6 model trained with Astra's methods |
| Artificial Analysis Intelligence Index (Oct 2026) | 52 | 53 | 38 |
| LMArena text score (Oct 8, 2026) | 1484 | 1475 | 1443 |
| OpenAI-reported comparison with Astra | Matches Astra on DeepSWE v1.1; within 2.1 points on OSWorld 2.0 (max effort) | Scored above GPT-6.1 Sol on Terminal-Bench Science 0.1 (68.1%) | Not reported in the GPT-6.1 Sol release |
| Available on Kie.ai | Yes | Yes | Yes |
What GPT-6.1 Sol Improves Over GPT-6 Sol
OpenAI built GPT-6.1 Sol as an upgrade to GPT-6 Sol for agentic coding, computer use and professional work such as understanding documents and running multi-step business workflows. These are the results OpenAI reports against GPT-6 Sol.
| Benchmark (OpenAI-reported) | What it measures | GPT-6.1 Sol vs GPT-6 Sol |
|---|---|---|
| DeepSWE v1.1 | Complex software-engineering tasks in real codebases | 6.4 points above GPT-6 Sol's best score, at a lower reasoning effort |
| AutomationBench | Multi-step business workflows | 4.8 points higher at medium reasoning effort |
| OSWorld 2.0 (offline set) | Demanding computer-use workflows | 7 points higher at maximum reasoning effort |
| Terminal-Bench Science 0.1 | Data analysis, simulation and theorem proving | More than double GPT-6 Sol's score at maximum reasoning effort |
| Factuality evaluation | Share of answers with at least one factual error | 11.4% to 7.7% at low reasoning effort, on deliberately difficult prompts that are not representative of typical usage |
Typical Uses for GPT-6.1 Sol
OpenAI built GPT-6.1 Sol for complex professional work. These are the kinds of tasks it was built for.
Coding Agents and Code Review
Writing, debugging and reviewing code in real codebases, where an agent works through complex software-engineering tasks.
Answers From Complex Documents
Questions answered from long PDFs with tables, charts, diagrams and fine print.
Multi-Step Business Workflows
Agents that carry a business task through several steps across different apps.
Computer-Use Agents
Agents that operate computer applications to complete multi-step tasks.
How to Use the GPT-6.1 Sol API on Kie.ai
Step 1. Get Your API Key
Step 2. Test Your Prompt in the Playground
Step 3. Send a Request
Tips Before You Ship
Web Search or Function Calling, Not Both
One request can use web search or your own function tools, not both. When you pass function tools, set tool_choice to auto; without function tools, leave tool_choice out.
Match the Dotted Model Name
Responses report the model as gpt-6.1-sol, with a dot, while requests use gpt-6-1-sol. If your code checks the model field, accept the dotted form.
Why Use GPT-6.1 Sol on Kie.ai
Same Key Across the Kie.ai Market
All models in the Kie.ai market use the same authentication method: an Authorization: Bearer YOUR_API_KEY header with the key from your Kie.ai API Key Management page.
Free Credits to Start
New Kie.ai users receive 80 free credits for testing. Your account has one credit balance that all generation services draw from, and you can check it with the Get Remaining Credits API.
Nothing to Host or Install
Kie.ai provides this model as an API with a playground; there is no app to download or install. There are no GPUs or model weights to manage.