Claude Opus 5 · No API key needed

The easiest way to use
Claude Opus 5

Aethyro puts Anthropic's most capable model in your browser. No API keys, no terminal, no monthly subscription — just credits you use when you need them.

Start free — 200 credits → Try without signing up

Why developers and researchers use Aethyro

Getting Claude Opus 5 directly via the Anthropic API means managing API keys, rate limits, billing setup, and token counting. Aethyro handles all of that — you get the same model, streaming responses, and full context window with none of the setup.

It's also cheaper for sporadic use. At $4 for 200 credits you can run dozens of long-form prompts before spending what a monthly API subscription would cost.

Aethyro vs. the alternatives

Feature Aethyro Anthropic API (direct) Claude.ai Pro
ModelClaude Opus 5Claude Opus 5Claude Opus 5
Setup requiredNoneAPI key + billingNone
Pricing modelPay-per-use packsPer-tokenMonthly $20/mo
No recurring charge✓Usage-basedSubscription
Browser-native UI✓Build it yourself✓
Conversation history✓Manage yourself✓
File / doc upload✓Build it yourself✓
Share conversations✓—Limited
Free starter credits200 creditsNoneNone

Frequently asked questions

Is this the real Claude Opus 5?
Yes. Aethyro uses Anthropic's official API. You're talking to the same model as the direct API, with no wrapper or fine-tuning applied.
What is a credit?
Credits are Aethyro's billing unit. One typical message costs 1–5 credits depending on its length and the length of the conversation history. The starter pack gives you 200 credits for $4.
Do credits expire?
No. Credits never expire. Buy a pack once and use it over weeks or months.
What's the context window?
Claude Opus 5 supports a 200k-token context window. Aethyro passes the full conversation history up to that limit on every request.
Can I use Aethyro without an account?
Yes — you can send a few messages with our trial chat on the homepage or at /app/chat.html without signing up. Creating a free account unlocks full conversation history and 200 starter credits.

Try Claude Opus 5 for free

Create a free account and get 200 credits instantly. No credit card required.

Get started free →