OpenAI o3

Text & chatDeprecatedAvailable
by OpenAIModel ID: openai-o3

OpenAI's o3 reasoning model. Spends compute on a private chain of thought before answering, strong at math, science and hard coding problems that benefit from deliberate reasoning.

Price · 1M in / out
US$2.40 / US$9.60
Context
200,000 tokens
Max. output
100,000 tokens
Input → output
Text + Image → Text
Developer
OpenAI
Updated
23 September 2026

The provider is phasing this model out.

01

Playground

Try OpenAI o3

Chat

US$2.40/1M in
Try OpenAI o3

Send a message. The answer arrives in full once the model is done (no streaming).

System prompt
Max. answer length (tokens)

This run

at most US$0.0099 · 0.99 credits reserved

Billed by the tokens actually used; the unused part of the reservation is refunded.

New here?

10 free credits (US$0.10) when you sign up with Google

Usable 24 hours after sign-up, up to 5 runs per day and at most 2 credits per run. Other sign-in methods start without credits. Enough for 10 runs of this model.

02

About OpenAI o3

TL;DRAs of 23 September 2026

OpenAI o3 is a model by OpenAI in the Text & chat category. On Railwail, OpenAI o3 costs US$2.40 per 1M input tokens and US$9.60 per 1M output tokens. The context window holds 200,000 tokens, and one response can be up to 100,000 tokens long.

03

Pricing

Prices in US dollars. Usage is charged from prepaid credits.
InputUS$2.40 / 1M tokens
OutputUS$9.60 / 1M tokens
  • Billed by the tokens each request actually uses.
  • 1 credit = US$0.01

Cost calculator

Price calculator

/ req.
/ req.

Total

US$0.72

72 credits

Per request

US$0.0072 · 0.72 credits

Each request is rounded up to 0.01 credits.

04

API

Call OpenAI o3 with your Railwail API key. Use this model ID in the request:
curl https://railwail.com/api/v1/chat/completions \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai-o3",
    "messages": [
      {
        "role": "user",
        "content": "Explain what a vector database is in two sentences."
      }
    ],
    "max_tokens": 1024
  }'
Set your key as RAILWAIL_API_KEYCreate API key
05

Specifications

Model ID
openai-o3
Developer
OpenAI
Category
Text & chat
Input
Text, Image
Output
Text
Context window
200,000 tokens
Max. output
100,000 tokens
Billing
By usage (tokens or GPU time)
Lifecycle
Deprecated
Catalog entry updated
23 September 2026

Tags

  • openai
  • o-series
  • reasoning
  • stem
  • vision
06

Use cases

07

Frequently asked questions

What is OpenAI o3?

OpenAI o3 is a model by OpenAI in the Text & chat category. On Railwail you can call it with an API key through the Railwail API.

How much does OpenAI o3 cost on Railwail?

On Railwail, OpenAI o3 costs US$2.40 per 1M input tokens and US$9.60 per 1M output tokens. You are charged for what each request actually uses. Usage is paid from prepaid credits; 1 credit equals US$0.01.

What is the context window of OpenAI o3?

The context window of OpenAI o3 holds 200,000 tokens. One response can be up to 100,000 tokens long.

How fast is OpenAI o3?

There are not enough measured runs of OpenAI o3 on Railwail yet to state a run time. It depends on the input, the settings and the load at the provider.

Is OpenAI o3 better than Claude Fable 5.1?

That depends on the task. OpenAI o3 (OpenAI) and Claude Fable 5.1 (Anthropic) are both models in the Text & chat category. The comparison page shows their prices and specifications side by side.

Compare OpenAI o3 and Claude Fable 5.1

Can OpenAI o3 process images?

Yes. OpenAI o3 accepts images as input in addition to text.

How do I use OpenAI o3 through the API?

Create a Railwail API key and send your request with the model ID openai-o3. Code examples for curl, Python and JavaScript are in the API section of this page.

08

Comparable models

All in this category
  • Anthropic's model for the most demanding reasoning and long-horizon agentic work. 1M-token context window, up to 128K output tokens, adaptive thinking that is always on.

    US$12.00/1M in

    400 % more expensive per unit

    Compare OpenAI o3 vs. Claude Fable 5.1
  • The most capable model of Anthropic's Opus 4 series. State of the art on long-horizon agentic work, coding and knowledge tasks, with a 1M-token context window at standard pricing.

    US$6.00/1M in

    150 % more expensive per unit

    Compare OpenAI o3 vs. Claude Opus 4.8
  • Anthropic's current Opus model for long-running agentic coding and knowledge work. 1M-token context window, up to 128K output tokens, adaptive thinking that is always on.

    US$4.80/1M in

    100 % more expensive per unit

    Compare OpenAI o3 vs. Claude Opus 5.5

Use OpenAI o3 via the API

One API key for every model on Railwail. Usage is charged from prepaid credits, 1 credit = US$0.01.