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GPT-6 Astra — Flagship Reasoning, 1.05M Context, 128K Output
GPT-6 Astra is OpenAI's most capable model, built for the hardest end-to-end work. GPT-6 Astra reads a 1,050,000-token context window, returns up to 128,000 tokens, takes text and images, and carries reasoning OpenAI rates Highest. On reAPI, GPT-6 Astra bills per token below OpenAI's published rate on every dimension.
- Highlights
- Reasoning rated Highest · five effort rungs · structured outputs
- Best for
- Complex reasoning, coding, research, documents
- Input
- Chat messages, text and image (OpenAI-compatible)
- Output
- Text, streaming optional
GPT-6 Astra· Chat Completions
Ask GPT-6 Astra
Start with the prompt in the composer or choose an example.
What is GPT-6 Astra?
GPT-6 Astra is OpenAI's flagship model, built for the hardest end-to-end work: complex reasoning, coding, computer use, research and document creation, carrying a task from the initial request to a finished result. On reAPI it is served through an OpenAI-compatible chat completions endpoint with a 1,050,000-token context window, up to 128,000 output tokens, text and image input, and reasoning OpenAI rates Highest. Billing is per token from your reAPI balance, with input and output priced separately and a higher rate for prompts over 272K tokens; reasoning tokens count as output.
What you can build with this model
Real-world workflows and production use cases you can build and ship with this model.
Work that has to be finished, not started
OpenAI positions GPT-6 Astra around end-to-end tasks: it combines reasoning, coding and document creation to carry a job from the initial request to a finished result using the context you provide. That is the shape of work to send it — a migration plan with every failure mode and its rollback, a review that has to be right, a decision memo built from a pile of threads. Ask GPT-6 Astra for the finished artefact and set the effort deliberately; ask it for a quick guess and you are paying the flagship rate for a cheaper tier's job.
Read the API docs
The whole codebase in one request
A 1,050,000-token context window means the service, its tests and its recent history go in as one request, so GPT-6 Astra reasons about the actual system rather than a summary of it. OpenAI's own guidance points the top of the effort ladder at complex debugging, security and code review and deep planning, and names GPT-6 Astra as the model to start with for reasoning workloads. Structured outputs are supported, so a review can come back as a schema your tooling consumes rather than prose someone has to parse.
Long documents, research and the judgement calls
There is a class of request where a wrong answer costs more than a month of inference: a contract review, an architectural commitment, a security finding, a research synthesis across hundreds of pages. GPT-6 Astra takes text and images at their original dimensions, reads the full 1.05M-token window, and its knowledge cutoff of April 2026 is the most recent in the catalogue. Route the routine turns to a cheaper sibling and keep GPT-6 Astra for the calls you would want your most senior colleague to make.
Pricing
Credit-based — 1 credit = $0.001 USD. Pay only for completed generations.
First test cost
$0.04848 credits
One 1K-token prompt with a 1K-token answer at the cheapest tier.
Testing budget guide
Add credits$10
≈ 208 tests
$50
≈ 1041 tests
$100
≈ 2083 tests
| Model | Category | Price |
|---|---|---|
| Standard · prompts up to 272K tokens | Input | $8 1M tokens |
| Output | $40 1M tokens | |
| Cache read | $0.8 1M tokens | |
| Cache write | $10 1M tokens | |
| Long context · prompts over 272K tokens | Input | $16 1M tokens |
| Output | $60 1M tokens | |
| Cache read | $1.6 1M tokens | |
| Cache write | $20 1M tokens |
Why reAPI
Below the published rate
OpenAI publishes per-million-token rates for GPT-6 Astra input and output, with a higher tier for prompts over 272K tokens. On reAPI, GPT-6 Astra bills below the published figure on every one of those dimensions, and the rates on this page are updated live. No subscription, no minimum commitment, pay-as-you-go from your reAPI balance. The live numbers are in the pricing table on this page.
OpenAI-compatible drop-in
GPT-6 Astra is served from reAPI's standard chat completions endpoint. If your code already speaks that shape, adopting GPT-6 Astra is a base URL, a key and a model string — the same SDKs work once the base URL points at reapi.ai. No SDK swap, no bespoke client.
One key, one balance, every model
The reAPI key that calls GPT-6 Astra is the same key that generates images and video on this platform, drawing from one balance. Send the routine turns to a cheaper chat model and escalate to GPT-6 Astra by changing a model string, not by opening an account with a second vendor.
GPT-6 Astra vs GPT-5.6 Sol
The decision a reader actually faces: whether to move up from the frontier tier of the GPT-5.6 family to GPT-6 Astra. The two share every documented limit — the 1.05M-token window, the 128K output ceiling, text and image input — and differ in reasoning depth, price and what reaches this endpoint. Neither is the general answer; the rows below are the ones that decide it for a given route.
Capability
GPT-6 Astra on reAPI
GPT-5.6 Sol
Vendor positioning
Our most capable model, built for the hardest end-to-end work; OpenAI's starting point for reasoning workloads
Frontier model for complex professional work; the target of the bare gpt-5.6 alias
Context and output limits
1,050,000-token context, 128,000-token maximum output
1,050,000-token context, 128,000-token maximum output
Reasoning effort
low, medium, high, xhigh reachable here; none is not supported; no default stated by OpenAI
none, low, medium, high, xhigh reachable here; defaults to medium
Tool calling on this endpoint
Not promised here — OpenAI documents tools for this model on the Responses API
Functions, web search, file search and computer use are documented for the family
Sampling parameters
Custom temperature, top_p and logprobs not supported; effort is the control
Reasoning effort is the intended control; sampling fields pass through
Price relationship
Higher rate per token, below OpenAI's published price, with a long-context tier over 272K tokens
Lower rate per token, below OpenAI's published price
Comparison reflects behavior documented by OpenAI at the time of writing. Rates are described as relationships rather than amounts; the live numbers for GPT-6 Astra are in the pricing table above.
Ship GPT-6 Astra in three steps
- step 01
Create a reAPI API key
Sign in to reAPI and create a key under API keys. That one key reaches GPT-6 Astra and every other model on the platform, billed from a single balance.
Open - step 02
Point your client at reapi.ai
Set your base URL to reapi.ai's API and your key to the one you just created. Any client that already speaks OpenAI Chat Completions works unchanged — no SDK swap is needed to reach GPT-6 Astra.
Open - step 03
Send gpt-6-astra as the model
Set the model field to gpt-6-astra and post your messages. Turn on streaming, set max_completion_tokens with room for reasoning, and choose the effort explicitly: OpenAI states no default for GPT-6 Astra, and the deep passes are what this model is for.
Open
docs/api/gpt-6-astra
curl https://reapi.ai/api/v1/chat/completions \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "gpt-6-astra",
"messages": [
{ "role": "user", "content": "Hello" }
],
"reasoning_effort": "high",
"max_completion_tokens": 16000,
"stream": true
}'Parameter validation failed
Rejected synchronously with the failing field named. Check enum values, ranges, and URL fields — nothing is charged.
Authentication or balance issue
401 means a missing or invalid Bearer key; 402 means the reserve exceeds your balance. Manage keys and credits in the console.
Content or material rejected
Reference material and outputs pass automated moderation. Rejected tasks fail with a clear error and a full refund.
Task failed or timed out
A task that reaches a failed state is never charged — the reserve refunds automatically. Keep the task id and retry when ready.
Frequently asked questions
Common questions about this model.
GPT-6 Astra is billed pay-as-you-go per token from your reAPI balance, with separate input and output rates and a higher tier for prompts over 272K tokens. Every rate sits below OpenAI's published figure. Current numbers are in the pricing table on this page.
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