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gpt-4o

OpenAIopenai

gpt-4o is a OpenAI chat and completion model you can call through flatkey.ai's OpenAI-compatible API. On flatkey it runs at $1.3333 per 1M input tokens — about 47% below the $2.5 official list price, and $5.3333 per 1M output tokens. One API key covers GPT, Claude, Gemini, DeepSeek, Seedance and 500+ other models, so you can switch models without changing SDKs or juggling separate accounts. Billing is prepaid with live usage analytics and a single invoice, which keeps spend predictable as you scale.

Get your API keySave ~47% vs official pricing
30-day success rate
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Throughput
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First-token latency
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Requests (30 days)
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Stacked discount
up to 50% offModels are priced at 60–90% of the official list. Top up $200 and get $100 free — both discounts stack, as low as 50% of the official price. →

Pricing

Input
List price $2.5
$1.3333/ 1M tokens
Output
List price $10
$5.3333/ 1M tokens
Cache read
List price $1.25
$0.666667/ 1M tokens

Specifications

Provider
OpenAI
Modality
Text / chat
Access
OpenAI-compatible API
Endpoints
openai

How to use the gpt-4o API

  1. 1
    Create a flatkey.ai account and API key
    Sign up for free, then generate an API key in the console. New accounts get bonus credit on their first top-up.
  2. 2
    Point your OpenAI client at flatkey
    Set base_url to https://router.flatkey.ai/v1 and use your flatkey key as the API key. No other code changes are needed — the API is OpenAI-compatible.
  3. 3
    Call gpt-4o
    Send a request with model set to "gpt-4o" using the OpenAI SDK or curl. Copy a ready-to-run example below.
API example
curl "https://router.flatkey.ai/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $FLATKEY_API_KEY" \
  -d '{"model":"gpt-4o","messages":[{"role":"user","content":"Say hello in one sentence."}]}'

gpt-4o vs similar models

ModelInput / 1M
gpt-4o$1.3333
gpt-4o-mini$0.08

Availability (last 30 days)

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Frequently asked questions

How much does the gpt-4o API cost?

On flatkey.ai, gpt-4o costs $1.3333 per 1M input tokens and $5.3333 per 1M output tokens, roughly 47% below the official list price. Top up $200 and get $100 free to stretch the budget further.

Is gpt-4o OpenAI-compatible?

Yes. Keep your existing OpenAI SDK, switch base_url to https://router.flatkey.ai/v1, and use your flatkey key. The model id stays "gpt-4o".

Is gpt-4o free to use?

Usage is pay-as-you-go, but priced well below the official list (about 47% cheaper), and new accounts receive bonus credit on their first top-up, so you can start testing at low cost.

How do I get an API key for gpt-4o?

Sign up on flatkey.ai, create an API key in the console, and add prepaid balance. You can start calling gpt-4o in minutes.

What other models can I use with the same key?

One flatkey key gives you GPT, Claude, Gemini, DeepSeek, Seedance and 500+ other models through a single OpenAI-compatible endpoint and one invoice.

How reliable is gpt-4o on flatkey?

We publish the live 30-day success rate, throughput and latency for gpt-4o directly on this page, updated from real traffic.

More OpenAI models

gpt-5.4$1gpt-5-mini$0.021333gpt-5.5$2gpt-image-2$2.66gpt-5.4-mini$0.3gpt-4.1-mini$0.213333

Start building with gpt-4o

One OpenAI-compatible key, prepaid billing, and bonus credit on your first top-up. Sign up in under a minute.

Get your API key