GPT Image 2.5 is now available — OpenAI's newest image model, released 8 September 2026. Billed per image at a flat $0.03, so prompt length and scene complexity never change the price. Each call returns one image of roughly 1.5 megapixels; the size parameter picks the aspect ratio. Requests to gpt-image-2 are now served by 2.5 at the same price, with no code changes.View pricing
OpenAI

GPT-6 Sol

Save 90%Official

openai/gpt-6-sol

The mid tier of GPT-6 for complex coding and professional work at a lower cost.

Context window
1.1M
Max output
128K
Input modalities
text · image
Output modalities
text
Capabilities
Vision · Reasoning · Tool calling · Coding · Prompt cache · Paid cache writes · Normalize Openai Envelope · Strip Responses Summary Input
Upstream release
2026-09-22
RouteMux name
openai/gpt-6-sol
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What is GPT-6 Sol

GPT-6 Sol is the middle tier of OpenAI's GPT-6 family, released in September 2026 alongside GPT-6 Luna. It brings much of GPT-6 Astra's capability to a faster, cheaper model, and OpenAI positions it for complex coding and professional work at scale: multi-file changes, agent loops that call tools many times, and analysis over long documents.

It accepts text and image input, supports tool calling and explicit prompt caching, and exposes reasoning effort as a request parameter from none all the way to max. That range lets one deployment answer quick turns without reasoning and still think hard on the steps that need it.

Through RouteMux it is $0.20 per 1M input tokens against OpenAI's $2, and $1.00 against $10 on output. It is reachable over OpenAI Chat Completions, OpenAI Responses, and Anthropic Messages, so an Anthropic-shaped client can call it without rewriting its request layer.

GPT-6 Sol API pricing

Source: openai_x0.10 · Verified 2026-09-23

InputOfficial $2 / M tokens
$0.2/ M tokensSave 90%
OutputOfficial $10 / M tokens
$1/ M tokensSave 90%

Fast $0.4 / $2 /M

Cache read $0.02/M · Cache write $0.25/M

TierInputCache readCache writeOutput
Standard ≤272K$0.2$2−90%$0.02$0.2−90%$0.25$2.5−90%$1$10−90%
Standard >272K$0.4$4−90%$0.04$0.4−90%$0.5$5−90%$1.5$15−90%
Priority ≤272K$0.4$4−90%$0.04$0.4−90%$0.5$5−90%$2$20−90%

Estimate cost

Estimated cost$0.003

Limited time20% extra Credits on your first top-up — up to 200 bonus Credits

Applies to your first top-up within 72 hours of signing up. Minimum $20, once per account.

Sign up and claimNo subscription. Pay for what you use.

Key capabilities

Built for complex work

Aimed at coding, agent workflows and professional knowledge work where Luna is not enough but Astra is more than the task needs.

Reasoning from none to max

Effort is a request parameter spanning none, low, medium, high, xhigh and max.

Vision and tools included

Image input, tool calling and explicit prompt caching are all supported.

Three protocols

OpenAI Chat, OpenAI Responses, and Anthropic Messages all route to this model.

Interface and protocols

OpenAI Chat CompletionsStreamingOpenAI ResponsesStreamingAnthropic MessagesStreaming

Use any of these IDs to call this model via the API.

RouteMux nameopenai/gpt-6-sol

Replace the ROUTEMUX_KEY placeholder with your API key. Create one →

from openai import OpenAI

client = OpenAI(
    base_url="https://api.routemux.com/v1",
    api_key="<ROUTEMUX_KEY>",
)

completion = client.chat.completions.create(
    model="openai/gpt-6-sol",
    messages=[{"role": "user", "content": "What is the meaning of life?"}],
)
print(completion.choices[0].message.content)
base_url: https://api.routemux.com/v1

Performance (last 30 days)

GPT-6 Sol FAQ

What is GPT-6 Sol?

The mid tier of GPT-6 for complex coding and professional work at a lower cost.

How large is the context window of GPT-6 Sol?

GPT-6 Sol supports a context window of up to 1.1M tokens, with up to 128K output tokens per request.

How much does the GPT-6 Sol API cost?

Through RouteMux, GPT-6 Sol costs $0.2 for input and $1 for output (USD per 1M tokens), below the official list price.

How do I call GPT-6 Sol via API?

GPT-6 Sol is OpenAI-compatible: point your base URL at RouteMux and set the model field to openai/gpt-6-sol — no code changes needed.

Which input and output modalities does GPT-6 Sol support?

GPT-6 Sol accepts text, image as input and produces text as output.

When was GPT-6 Sol released?

GPT-6 Sol was released on September 22, 2026.

How do Sol, Luna and Astra differ?

They are the three tiers of GPT-6. Luna is the high-volume tier for simple, well-defined steps; Sol is the everyday tier for complex coding and agent work; Astra is the flagship for the hardest problems.

Can reasoning be turned off?

Yes. Sol accepts a reasoning effort of none, as well as low, medium, high, xhigh and max.

Does the price change for very long inputs?

Yes. Requests whose input exceeds 272K tokens bill at the long-context rate. The pricing section above lists every tier.

Sources