GPT-5.6 Sol
Provider list prices: no platform markup, pay-as-you-go. These are official list prices. Logged-in customers may see effective prices including workspace discounts on /console/pricing. Effective input at a 70% cache-hit rate:$1.85/M. Automatic prefix caching once a prompt passes the minimum length, with no code changes; cached reads are discounted (up to 90% on current models) and there is no write fee. Family flagship for frontier reasoning and long-horizon agentic work; introduces the max reasoning effort and an ultra mode that coordinates subagents; the bare gpt-5.6 alias routes to Sol; prompts over 272k input tokens billed at 2x input / 1.5x output.
Use GPT-5.6 Sol in 30 seconds
OpenAI-compatible: swap the base_url, keep your SDK. POST /v1/chat/completions
from openai import OpenAI
client = OpenAI(
base_url="https://synthorai.io/v1",
api_key="sk-syn-...",
)
resp = client.chat.completions.create(
model="gpt-5.6-sol",
messages=[{"role": "user", "content": "Summarize this diff"}],
reasoning_effort="medium",
)
print(resp.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://synthorai.io/v1",
apiKey: "sk-syn-...",
});
const resp = await client.chat.completions.create({
model: "gpt-5.6-sol",
messages: [{ role: "user", content: "Summarize this diff" }],
reasoning_effort: "medium",
});
console.log(resp.choices[0].message.content);curl https://synthorai.io/v1/chat/completions \
-H "Authorization: Bearer sk-syn-..." \
-H "Content-Type: application/json" \
-d '{
"model": "gpt-5.6-sol",
"messages": [{"role": "user", "content": "Hello"}],
"reasoning_effort": "medium"
}'package main
import (
"context"
"fmt"
"github.com/openai/openai-go/v3"
"github.com/openai/openai-go/v3/option"
)
func main() {
client := openai.NewClient(
option.WithBaseURL("https://synthorai.io/v1"),
option.WithAPIKey("sk-syn-..."),
)
resp, _ := client.Chat.Completions.New(context.TODO(), openai.ChatCompletionNewParams{
Model: "gpt-5.6-sol",
Messages: []openai.ChatCompletionMessageParamUnion{
openai.UserMessage("Summarize this diff"),
},
ReasoningEffort: openai.ReasoningEffortMedium,
})
fmt.Println(resp.Choices[0].Message.Content)
}import com.openai.client.OpenAIClient;
import com.openai.client.okhttp.OpenAIOkHttpClient;
import com.openai.models.chat.completions.*;
import com.openai.models.ReasoningEffort;
OpenAIClient client = OpenAIOkHttpClient.builder()
.baseUrl("https://synthorai.io/v1")
.apiKey("sk-syn-...")
.build();
ChatCompletion resp = client.chat().completions().create(
ChatCompletionCreateParams.builder()
.model("gpt-5.6-sol")
.addUserMessage("Summarize this diff")
.reasoningEffort(ReasoningEffort.MEDIUM)
.build());
System.out.println(resp.choices().get(0).message().content().orElse(""));About GPT-5.6 Sol
GPT-5.6 Sol is the flagship of OpenAI's GPT-5.6 family, built for frontier reasoning and long-horizon agentic work; OpenAI positions it for the hardest problems, such as complex coding and security research.
- It combines a 1,050,000-token context window (vendor spec) and 128K max output tokens with image input and the full hosted tool suite (web search, file search, code interpreter, hosted shell, computer use, MCP), with a February 2026 knowledge cutoff.
- The generation introduces a new max reasoning-effort setting that gives Sol more time to reason deeply, plus an ultra mode that coordinates subagents on complex workflows, and the bare gpt-5.6 alias routes to Sol as the family default.
- Synthorai serves GPT-5.6 Sol natively on its OpenAI-compatible API.
Specs & limits
| Max output (vendor spec) | 128,000 |
| Modalities | text + image → text |
| Features | reasoning · vision · code · tools · caching |
| Notable | Family flagship for frontier reasoning and long-horizon agentic work; introduces the max reasoning effort and an ultra mode that coordinates subagents; the bare gpt-5.6 alias routes to Sol; prompts over 272k input tokens billed at 2x input / 1.5x output. |
| Prompt caching | automatic · min 1,024-token prefix · TTL 5–10m, up to 1h |
FAQ
Is the GPT-5.6 Sol API free to try?
Yes: new accounts get 10 trial calls and up to $1 in free credit, no card required. At $5/M input tokens, that credit alone covers roughly 24 requests of ~8K tokens against GPT-5.6 Sol.
What is GPT-5.6 Sol best at?
Frontier reasoning and long-horizon agentic work, plus new max reasoning effort plus ultra mode with subagents and the bare gpt-5.6 alias routes here by default. See the About section for the full picture from the vendor's own release notes.
How much does GPT-5.6 Sol cost?
GPT-5.6 Sol costs $5 per million input tokens and $30 per million output tokens on Synthorai. That is the provider's list price, with no platform markup. Cached input tokens bill at $0.5/M.
Does GPT-5.6 Sol support prompt caching?
Yes, automatically: OpenAI-served prompts cache with no code changes. Cached input tokens bill at $0.5/M vs $5/M uncached; prompts need a 1,024-token stable prefix to cache (TTL 5–10m, up to 1h). Prompt caching guide →
How do I get access to GPT-5.6 Sol?
Point your existing OpenAI SDK at base_url="https://synthorai.io/v1", set model="gpt-5.6-sol", and you're done. One API key covers every model on the gateway.
What is GPT-5.6 Sol's knowledge cutoff?
GPT-5.6 Sol's knowledge cutoff is 2026-02, per the vendor's official documentation (as of 2026-07-10).