How to obtain a Claude API key — official and gateway routes

There are two ways to get a Claude API key. The official route is to create one directly in the Anthropic Console; the other is to get one from a gateway that provides an Anthropic-compatible endpoint. Both call the same Claude models; in your code, only the base URL and key string differ.

Below, we cover both routes and also address payment issues that commonly arise in South Korea.

Route 1 — Create a key directly in the Anthropic Console

Create an Anthropic account, add a payment method, then generate an API key in the console. Keys created this way are billed at Anthropic's list rates, with the benefit of access to official documentation and support.

In South Korea, payment is where most people run into trouble. Cards that block international payments cannot be registered, so enabling international payments in your card issuer's app and trying again resolves the issue in most cases.

Route 2 — Gateway key

This lets you call Claude models without an Anthropic account. Kunavo provides both the Anthropic Messages API and an OpenAI-compatible API, so you only need to change the base URL and key in your existing code.

This route also encounters fewer obstacles at the payment stage. For prepaid Kunavo top-ups, when checkout is displayed in Korean won, KakaoPay, Naver Pay, PAYCO, Samsung Pay, and domestic cards with international payments disabled are offered as payment methods (Toss Pay is not offered). The topped-up balance is used for Claude API calls; it is not a way to pay Anthropic subscription fees.

# OpenAI SDK를 그대로 쓰면서 base_url만 바꾸는 방식.
# 코드에서 바뀌는 줄은 base_url 한 줄뿐입니다.
from openai import OpenAI

client = OpenAI(
    base_url="https://api.kunavo.com/v1",
    api_key="sk-kn-...",
)

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

If your code uses the native Anthropic format, set the base URL to https://api.kunavo.com — in this case, do not add /v1. The differences between the two formats are explained in the ANTHROPIC_BASE_URL documentation.

Rates

Rates are read from the catalog when the page renders, so this documentation cannot diverge from actual charges. For more details about payment methods and locally issued cards, see Claude API pricing and payment.

30-second check after creating a key

Once you have a key, make a call right away. Checking this first makes it easy to tell whether later errors are caused by the key.

# 발급받은 키가 실제로 동작하는지 확인하는 최소 요청.
# 200이 오면 키는 정상입니다.
curl -sS https://api.kunavo.com/v1/messages \
  -H "Authorization: Bearer sk-kn-..." \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{"model":"claude-sonnet-5","max_tokens":32,
       "messages":[{"role":"user","content":"안녕하세요"}]}'

A 200 means the key is working. 401 usually means the authentication header type is incorrect; 429 indicates rate limiting, and 529 indicates upstream overload, unrelated to the key. See Claude Code error guide for how to handle each error.

Using separate keys

It is safer to use separate keys for different purposes. Revoking one does not affect the others, and you can set a monthly usage limit for each key. Limits are checked before a request runs and reset at the start of each month, making this especially useful when giving a key to an agent that runs without supervision.

Frequently asked questions