Alternatives

An Anthropic API alternative with one key for 50+ models

Anthropic provides its Claude models through the Claude API (the Anthropic API), with its own SDKs and Messages API format.

What developers use it for

  • Long-document analysis and writing with Claude
  • Coding assistants and agents
  • Teams that want Claude specifically

Things to consider

  • The native Messages API differs from the OpenAI chat format, so switching providers usually means code changes.
  • Only Claude models are available on the Anthropic API.

Where Somnus fits

Through Somnus you call Claude models with the OpenAI-style chat format, alongside other makers' models, from the same key.

Every Somnus top-up is credited at 2× or more, and usage is billed at each model's list price, so a dollar of credit buys at least two dollars of usage.

Calling Somnus with the OpenAI SDK

python
from openai import OpenAI
import os

client = OpenAI(
    api_key=os.environ["SOMNUS_API_KEY"],
    base_url="https://somnus.world/api/public/gateway/v1",
)

resp = client.chat.completions.create(
    model="claude-sonnet-5",
    messages=[
      {"role": "user", "content": "Hello"}
    ],
)
print(resp.choices[0].message.content)

Somnus uses the OpenAI chat-completions format, so you use the openai package instead of a provider-specific SDK.

Questions

Is Somnus affiliated with Anthropic?

No. Somnus is independent. This page summarises Anthropic's public information, linked below.

Can I keep using Anthropic too?

Yes. Many teams use Somnus for multi-model access alongside a direct provider account.

Is there a free trial?

New Somnus accounts start with $10 of free credit after card verification.

Sources

Last checked 2026-09-29. Prices and features of other providers change — confirm on their sites.

Explore Somnus as another API option

Try it side by side with Anthropic — new accounts get $10 of free credit after card verification.

Create a free account

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