GPT-5.6 Sol API

GPT-5.6 Sol is the flagship of OpenAI's GPT-5.6 series, generally available since July 2026. The series introduced OpenAI's tier names: Sol at the top, Terra in the middle and Luna for speed and low cost. In Jantaris, GPT-5.6 Sol has a 1,050,000-token context window and up to 128K output tokens. OpenAI describes it as suited to complex reasoning, coding and agentic workflows, and particularly strong at command-line work and multi-step coding tasks.

Best for

• Terminal-based coding agents and scripted automation
• Multi-step bug fixing across several files
• Complex reasoning where earlier GPT models were not enough
• Existing apps built and evaluated on GPT-5.6 Sol

How to call it

Standard OpenAI SDK, Jantaris base URL:

from openai import OpenAI

client = OpenAI(base_url="https://jantaris.com/v1", api_key="sk-jt-...")
resp = client.chat.completions.create(
    model="gpt-5.6-sol",
    messages=[{"role": "user", "content": "Write a bash script that rotates logs older than 7 days."}],
)
print(resp.choices[0].message.content)

FAQ

How much does GPT-5.6 Sol cost?

$4.32 / $21.60 per 1M tokens in Jantaris. The price is fixed per model and visible before you send a request, and there is no monthly fee on top.

GPT-5.6 Sol or GPT-6 Sol?

GPT-6 Sol is the newer generation of the same tier. If you are starting a new project, test GPT-6 Sol first. If your production prompts were tuned on GPT-5.6 Sol, keep it until you have compared both on your own data.

Can I use GPT-5.6 Sol in coding tools like Cursor or Cline?

Yes. Tools that accept an OpenAI-compatible endpoint work with https://jantaris.com/v1, your sk-jt- key and gpt-5.6-sol as the model name. See the Claude Code and IDE guide for the settings of each tool.

How to call GPT-5.6 Sol via API

from openai import OpenAI

client = OpenAI(base_url="https://jantaris.com/v1", api_key="sk-jt-...")
resp = client.chat.completions.create(
    model="gpt-5.6-sol",
    messages=[{"role": "user", "content": "Write a haiku about Baltic amber."}],
)
print(resp.choices[0].message.content)

curl https://jantaris.com/v1/chat/completions \
  -H "Authorization: Bearer $JANTARIS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-5.6-sol", "messages": [{"role": "user", "content": "Write a haiku about Baltic amber."}]}'

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://jantaris.com/v1", apiKey: process.env.JANTARIS_API_KEY });
const resp = await client.chat.completions.create({
  model: "gpt-5.6-sol",
  messages: [{ role: "user", content: "Write a haiku about Baltic amber." }],
});
console.log(resp.choices[0].message.content);