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New — Fable 5 & Sonnet 5, live

The whole Claude lineup.
One key. No waitlist.

Access every Claude model — from Haiku to Fable 5 — through a single API key. Pay per token with transparent pricing, rolling budgets, and zero markups.

Explore Plans & PricingView Documentation
Instant API key deliveryPay via UPI or Cards5h rolling token budgetsZero markup pricing
quickstart terminal
$ export ANTHROPIC_BASE_URL=https://api.opuszen.shop
$ export ANTHROPIC_API_KEY=sk-ant-zen-your-key-here
$ npx opuszen█
model: claude-fable-5context: 1M windowplan: transparent token rates

01 — The lineup

The whole Claude & AI model lineup. One endpoint.

New1M context

Claude Fable 5

claude-fable-5

Most intelligent, best for complex reasoning

1M contextpro
New1M context

Claude Opus 5

claude-opus-5

Highest capability for complex tasks

1M contextpro

Claude Sonnet 5

claude-sonnet-5

Balanced performance and speed

200K contextpro

Claude Haiku 4.5

claude-haiku-4-5-20251001

Fast and affordable

200K contextdev

02 —Built for people who ship

Budgets that hold, streaming that doesn't buffer, and tools that are already switched on.

$7.50

Per-key rolling budgets

Set per-key spending limits with 5-hour rolling windows. Each key gets its own budget, expiry, and rate limits.

SSE

Direct streaming

Zero-latency SSE streaming pass-through. Responses stream in real-time, just like Anthropic's API.

0.25x

Free prompt caching

Prompt caching is free — cache hits cost just 0.25x the normal rate. Save money on repeated prompts.

SDK

Drop-in SDK compatible

Works with the official Anthropic SDK, Claude Code, Python, Node.js, and any OpenAI-compatible client.

Tools

Server-side tools

Use tool use and function calling with full server-side orchestration. No client-side complexity needed.

Dashboard

Readable usage dashboard

Track every request, token, and cost in a clean dashboard. Monitor usage across all keys and models.

Works where you already work

Claude Code
Cursor
VS Code
Windsurf
Cline
Roo Code
Zed
Anthropic SDK
Claude Code
Cursor
VS Code
Windsurf
Cline
Roo Code
Zed
Anthropic SDK

03 —Migration

Change one line in your existing code. Everything else stays the same.

Before
const client = new Anthropic({
baseURL: "https://api.anthropic.com",
});
After
const client = new Anthropic({
baseURL: "https://api.opuszen.shop",
});

Ready in 60 seconds

Three steps. That's it.

01

Get your API key

Your admin or reseller creates a key with budget and rate limits already configured.

02

Set your base URL

Point any Anthropic-compatible client to opuszen.live. Everything else stays the same.

03

Start building

Claude Code, Python SDK, cURL, Cursor — it all just works. Streaming included.

Why OpusZen

Built for teams that need control

Multi-tenant API key management with per-key budgets, rate limits, usage tracking, and a full admin dashboard. Designed for resellers and teams.

  • Per-key budgets with 5h rolling windows
  • Isolated rate limits & expiry per key
  • Zero-latency SSE streaming pass-through
  • Prompt caching — cache tokens are free
  • Drop-in Anthropic SDK compatible
  • Works with Claude Code, Cursor, any IDE

Ready to supercharge your AI workflow?

Join thousands of developers using OpusZen for instant access to every Claude model.

Instant API key delivery
UPI & Card Checkout

04 — Getting started

Three steps. Under two minutes.

01

Select a Plan

Choose a plan based on your needs.

02

Buy plan

Buy a plan using UPI. You get encrypted API Key immediately.

03

Use it

Use your OpusZen API Key. That's it.

Two thousand developers already build on OpusZen

No waitlist. No approval needed.

View Pricing & Plans
$ npx opuszen█