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GPT-6 Sol — strong reasoning for coding and agent work

GPT-6 Sol is built for complex coding and agentic workflows, with a 1.05M-token context. $0.20 / 1M input, $1.00 / 1M output per 1M tokens.

Available$0.20 / 1M input · $1.00 / 1M output$2.00 / 1M input · $10.00 / 1M output-90%
  • Reasoning effort control
  • 1.05M-token context
  • Image input
  • Prompt caching
  • Streaming
Context window
1.05M tokens
Max output
128K tokens
Effort levels
none to max
Knowledge cutoff
Apr 20, 2026

Try GPT-6 Sol

Chat with GPT-6 Sol, attach images, and see the tokens and cost of every answer.

Parameters
gpt-6-sol$0.20 in · $1.00 out per 1M tokens
Reasoning effort
Reasoning summary
Reasoning mode
Reasoning context
Verbosity

Temperature and Top P work only with reasoning effort none.

Conversation total$0.000000
Ready

Try one of these prompts

Messages are billed from your balance at the rates below, like an API call. Failed requests are free.

Real GPT-6 Sol output

One prompt, sent to GPT-6 Sol at low reasoning effort. Unedited.

Explain the difference between a mutex and a semaphore in two short paragraphs, and say when to use each.

A mutex is a lock that lets one thread access a shared resource at a time. The thread that locks it must unlock it. Use a mutex to protect shared data or a critical section from simultaneous access. A semaphore is a counter that controls how many threads can proceed. Use one to limit access to a pool of resources, such as a fixed number of database connections, or to signal that work is ready.

Generated 2026-09-28. Answers vary from run to run.

GPT-6 Sol pricing

GPT-6 Sol is billed per token from your balance. Rates below are live, the same ones your account is charged.

One typical request2,000 input tokens, 1,000 output tokens
$0.0014per request
Reasoning counts as output, so higher effort raises the output side.
What $20.00 buysOutput tokens at the current rate
20,000,000output tokens
Input and cached tokens cost less per token than output.

Example sizes are for illustration. Your bill follows the tokens each request reports.

CategoryDefaultgpt-6-solgpt officialgpt-6-sol:gpt-0.7
≤ 272,000 input tokensPrice · 1M tokens> 272,000 input tokensPrice · 1M tokens≤ 272,000 input tokensPrice · 1M tokens> 272,000 input tokensPrice · 1M tokens
Input$0.20$0.40$1.40$2.80
Output$1.00$1.50$7.00$10.50
Cached input$0.02$0.04$0.14$0.28
Cache write$0.25$0.50$1.75$3.50

Total input includes cache reads and writes. The selected tier applies to every token category in the request. Examples use the standard tier.

What is GPT-6 Sol?

GPT-6 Sol is OpenAI's GPT-6 model for complex coding and agentic workflows. It sits between GPT-6 Astra, the most capable model, and GPT-6 Luna, the most efficient one. GPT-6 Sol reads up to 1.05M tokens of context and writes up to 128K tokens per request.

GPT-6 Sol lets you choose how hard it thinks: reasoning effort runs from none to max, and the default is medium. At none it answers without reasoning and accepts temperature and top_p, which suits fast, simple steps.

Model ID: gpt-6-sol · Input: text, images · Output: text · Formats: OpenAI Responses, OpenAI Chat Completions, Anthropic Messages.

Model ID
gpt-6-sol
Context window
1.05M tokens
Max output
128K tokens
Effort levels
none to max
Input
Text, images

Two ways to use GPT-6 Sol

Call it from your code, or let your coding agent do it for you.

API

Call it from your backend

Best for apps and services

Point the official OpenAI SDK at SeedRouter and keep your code. GPT-6 Sol answers both the Responses and Chat Completions formats.

  1. 1Create an API key
  2. 2Set the base URL to https://api.seedrouter.ai/v1
  3. 3Send gpt-6-sol as the model
Agent

Hand it to your coding agent

Best for Claude Code, Codex and other agents

Copy a ready prompt. Your agent shows the request and cost before anything is spent.

  1. 1Copy the prompt
  2. 2Paste it into your agent
  3. 3Approve the request

What GPT-6 Sol is good at

GPT-6 Sol is made for work you repeat every day: building features, reviewing code and analysing data.

Everyday coding

GPT-6 Sol writes, reviews and debugs code across a real codebase.

Agent workflows

A 1.05M-token context lets an agent run many steps without losing the thread.

Data analysis

Hand GPT-6 Sol tables, logs or reports and get a clear read on them.

Images in the prompt

GPT-6 Sol reads screenshots and charts alongside your text.

Effort you control

None for quick answers, max for hard problems. Pay for the reasoning you ask for.

Cheaper repeat context

Cached input on GPT-6 Sol costs 10% of the input rate.

What teams build with GPT-6 Sol

Code review bots

Run GPT-6 Sol on every pull request and post findings back.

Support assistants

Answer from your docs with the whole knowledge base in context.

Structured extraction

Turn tickets and invoices into JSON with a text.format schema.

Start using GPT-6 Sol in four steps

  1. 01

    Create a key

    Sign in and create an API key. Add credit whenever you need it; there is no subscription.

  2. 02

    Change the base URL

    Point the OpenAI SDK at https://api.seedrouter.ai/v1. Your code stays the same.

  3. 03

    Pick GPT-6 Sol

    Send gpt-6-sol as the model. Set reasoning effort to trade depth for speed and cost.

  4. 04

    Check the bill

    Every request shows its tokens and charge in your usage records.

Get an API key

GPT-6 Sol on SeedRouter at a glance

What you can use today.

OpenAI Responses
Yes, official format
OpenAI Chat Completions
Yes
Anthropic Messages
Yes
Image input
Yes, by URL
Streaming
Yes
Prompt caching
Yes, cached input and cache writes billed apart
Reasoning effort none
Yes
Failed requests
Not charged

Batch, Flex, background mode and service tiers are not offered.

GPT-6 Sol limits

1.05M-token context

On GPT-6 Sol, prompt, images and history share one 1.05M-token window; input is capped at 922K.

128K tokens out

One GPT-6 Sol request can return up to 128K tokens, reasoning included.

Long prompts cost more

Above 272K input tokens, the whole GPT-6 Sol request is billed at the higher long-context rates.

Sampling needs effort none

GPT-6 Sol accepts temperature and top_p only when reasoning effort is none.

Why call GPT-6 Sol through SeedRouter

One key, three formats

Call GPT-6 Sol with OpenAI Responses, Chat Completions or Anthropic Messages, using the same key.

Pay per token

Top up once and spend it on any model. No plan, no monthly fee.

Failures are free

A request that errors is not charged.

Live prices

The rates on this page are the rates your account pays.

Prompt caching

Repeated prompt prefixes are read from the cache at a lower GPT-6 Sol rate.

Image input

Send screenshots, charts and photos by URL with your prompt.

Streaming

Stream GPT-6 Sol tokens as they arrive with stream: true.

Related models

Other models you can call with the same key.

GPT-6 Astra
gpt-6-astra

Call GPT-6 Astra with the OpenAI SDK. OpenAI's most capable model, with a 1.05M-token context, live per-token pricing and a playground you can try right now.

View pricing
GPT-6 Luna
gpt-6-luna

Call GPT-6 Luna with the OpenAI SDK. The lowest-cost GPT-6 model, with a 1.05M-token context, live per-token pricing and a playground you can try right now.

View pricing
GPT-6.1 Sol
gpt-6.1-sol

Call GPT-6.1 Sol with the OpenAI SDK: near-Astra coding and agent work at a fifth of the price, 1.05M-token context, 95% off cached input. Try it now.

View pricing
Claude Fable 5
claude-fable-5

Call Claude Fable 5 with the Anthropic or OpenAI SDK. Deep reasoning, 1M-token context, forced tool use, live per-token pricing and a playground to test it.

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Claude Fable 5.1
claude-fable-5-1

Call Claude Fable 5.1 with the Anthropic or OpenAI SDK. Deep reasoning, 1M-token context, cheap cached reads, live pricing and a playground to try it today.

View pricing
Claude Fable 5.2
claude-fable-5-2

Try Claude Fable 5.2 for coding and problem solving with a 1M-token context. Compare live token prices and model tiers, then test it in the playground.

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GPT-6 Sol guides

Walkthroughs and comparisons for this model.

GPT-6.1 Sol pricing: per-token rates, caching and real request costs

GPT-6.1 Sol pricing explained: input, cached input, cache write and output rates, the 272K long-context rule, worked request costs and how to spend less.

GPT-6.1 Sol reasoning effort: low, medium, high, xhigh or max?

Which GPT-6.1 Sol reasoning effort to use: real timings, token counts and costs at low, medium, high, xhigh and max, why it feels slow, and where to start.

GPT-6.1 Sol vs GPT-6 Astra vs GPT-6 Sol: is it better?

GPT-6.1 Sol vs GPT-6 Astra and GPT-6 Sol: specs, prices, the benchmark gaps OpenAI published, what changed from GPT-6 Sol and which model to use.

OpenRouter alternative: the same GPT-6, Claude and DeepSeek models at lower per-token prices

An OpenRouter alternative for GPT-6, Claude and DeepSeek: per-token prices compared, the 5.5% credit fee, free model limits and how to switch your base URL.

GPT-6 in Codex: setup, tested configs and common errors

How to run GPT-6 Astra, Sol and Luna in OpenAI Codex CLI with a SeedRouter key: the config.toml, the context window setting, test results and common errors.

GPT-6 release date: when GPT-6 Astra, Sol and Luna came out

When was GPT-6 released? GPT-6 Astra launched on September 3, 2026, and GPT-6 Sol and Luna on September 22. How the rollout went and where to use GPT-6 today.

Is GPT-6 free? What Free, Plus, Pro, students and API users get

Is GPT-6 free? Free and Go users get GPT-6 Luna in the ChatGPT desktop app. GPT-6 Astra needs a paid plan, and the API is paid per token.

GPT-6 API: how to get a key and call Astra, Sol and Luna

How to access the GPT-6 API: get a key, call GPT-6 Astra, Sol or Luna with the OpenAI SDK, set reasoning effort, stream, send images and avoid common errors.

GPT-6 API pricing: Astra, Sol and Luna cost per million tokens

GPT-6 API pricing for Astra, Sol and Luna per million tokens: input, output, cached input, cache writes and the 272K long-context rate, with worked examples.

GPT-6 Astra vs Sol vs Luna: which GPT-6 model to use

GPT-6 Astra vs Sol vs Luna compared: specs, prices, OpenAI benchmark results, reasoning effort and a clear pick for coding, agents and high-volume work.

GPT-6 vs Claude Opus 5.5: benchmarks, prices and which to use

GPT-6 Astra, Sol and Luna vs Claude Opus 5.5: specs, token prices, the benchmark results both labs published, and which model fits coding, agents and cost.

GPT-6 vs GPT-5.6: prices, specs and what changed

GPT-6 vs GPT-5.6 compared: Sol and Luna at half the price, the same 1.05M context, newer knowledge, OpenAI benchmark gains and what to change when you migrate.

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GPT-6 Sol FAQ

What is GPT-6 Sol?+

GPT-6 Sol is OpenAI's GPT-6 model for complex coding and agentic workflows. It has a 1.05M-token context window, writes up to 128K tokens per request and lets you set reasoning effort from none to max.

Should I use GPT-6 Sol, GPT-6 Astra or GPT-6 Luna?+

Use GPT-6 Astra for the hardest end-to-end work, GPT-6 Sol for demanding coding and agent tasks at a lower price, and GPT-6 Luna for focused, high-volume jobs where cost matters most.

How much does GPT-6 Sol cost?+

GPT-6 Sol is billed at $0.20 / 1M input and $1.00 / 1M output per 1M tokens. Cached input costs 10% of the input rate. Prompts above 272K tokens use the long-context rates shown in the pricing table.

What is the default reasoning effort of GPT-6 Sol?+

GPT-6 Sol defaults to medium. You can set none, low, medium, high, xhigh or max; none turns reasoning off and is the only level that accepts temperature and top_p.

What is the knowledge cutoff of GPT-6 Sol?+

GPT-6 Sol has a knowledge cutoff of April 20, 2026. For newer facts, pass them in the prompt.

What is the GPT-6 Sol model ID and how do I call it?+

The model ID is gpt-6-sol. Create a SeedRouter API key, point the OpenAI SDK at https://api.seedrouter.ai/v1 and send gpt-6-sol as the model with the Responses or Chat Completions API.

Can GPT-6 Sol read images?+

Yes. GPT-6 Sol accepts images alongside text, sent by URL in the request. It returns text only.

Am I charged if a GPT-6 Sol request fails?+

No. A GPT-6 Sol request that returns an error is not charged. You pay only for the tokens a finished request reports.

Try GPT-6 Sol now

Send your first GPT-6 Sol request from the playground or your own code in minutes.