A lower-cost way to connect GPT applications
Compare an OpenAI-compatible API on the dimensions that matter: current model price, reliability, latency, limits, and how much code you need to change.
OpenAI-compatible endpoint
Use the standard /v1/chat/completions endpoint with the official OpenAI SDK or any client that accepts a custom base URL. The same integration can be used from Python, JavaScript, cURL, Cursor, Codex, and other development tools.
from openai import OpenAI
client = OpenAI(
api_key="sk-your-api-key",
base_url="https://relay.fast/v1",
)
response = client.chat.completions.create(
model="gpt-6.1-sol",
messages=[{"role": "user", "content": "Reply with OK"}],
)A practical migration checklist
- Set the base URL to
https://relay.fast/v1and keep your API key in an environment variable. - Call
/v1/modelsto discover the models enabled for your account. - Compare output quality, latency, error handling, and total token cost on representative prompts.
When this route is a good fit
cheap OpenAI API guide is useful when you already use the OpenAI SDK and want to evaluate another provider without rewriting your application. It is also a useful starting point for prototypes where predictable pay-as-you-go billing matters more than a bundled consumer subscription.
Do not choose on a headline discount alone. Compare the same prompts, token mix, tool calls, latency targets, and failure recovery in a small test before moving production traffic.
Current GPT model prices
Prices checked from the live catalog. "From" is the lowest price among the relay.fast sources that currently serve the model. The price you pay depends on the source your request uses and can change on any day. The pricing page always shows current values.
| Model | Model ID | Official input / output per 1M tokens | relay.fast from, input / output | Cache read from | Context |
|---|---|---|---|---|---|
| GPT-6.1 Sol requests above 272K input tokens cost more | gpt-6.1-sol | $2 / $10 | $0.03 / $0.15 (−98%) | $0.0015 | 1.05M |
| GPT-6 Sol requests above 272K input tokens cost more | gpt-6-sol | $2 / $10 | $0.03 / $0.15 (−98%) | $0.003 | 1.05M |
| GPT-6 Astra requests above 272K input tokens cost more | gpt-6-astra | $10 / $50 | $0.1 / $0.5 (−99%) | $0.01 | 1.05M |
| GPT-6 Luna requests above 272K input tokens cost more | gpt-6-luna | $0.1 / $0.5 | $0.008 / $0.04 (−92%) | $0.0008 | 1.05M |
| GPT-5.6 Sol requests above 272K input tokens cost more | gpt-5.6-sol | $5 / $30 | $0.075 / $0.45 (−98%) | $0.0075 | 1M |
| GPT-5.6 Terra requests above 272K input tokens cost more | gpt-5.6-terra | $2 / $12 | $0.03 / $0.18 (−98%) | $0.003 | 1M |
| GPT-5.6 Luna requests above 272K input tokens cost more | gpt-5.6-luna | $0.2 / $1.2 | $0.016 / $0.096 (−92%) | $0.0016 | 1M |
| GPT-5.5 requests above 272K input tokens cost more | gpt-5.5 | $5 / $30 | $0.075 / $0.45 (−98%) | $0.0075 | 272K |
Frequently asked questions
Is this an official OpenAI API key?
No. relay.fast is a separate API gateway. Use a relay.fast key and the documented base URL; do not paste an OpenAI secret into a third-party service.
How do I know whether it is cheaper?
Use the live catalog and your own token mix. Prices and model availability can change, so a workload-specific comparison is more reliable than a permanent cheapest claim.
Can I keep the OpenAI SDK?
Yes. Point the SDK at the relay.fast OpenAI-compatible base URL and select a model listed by /v1/models.