Claude API: model selection and connection

Models and current API429 rates

These are exact text model IDs for this family. The public catalog and GET /v1/models for your key answer different questions: a published entry does not prove account access. Preserve hyphens, dots and versions exactly.

Catalog data date: Oct 25, 2026, 8:23 AM UTC. Rates retain their catalog conditions; an absent row does not mean a free request.

Example budget for claude-sonnet-5-5: 1,000 requests with 2,000 ordinary input and 500 output tokens each cost approximately $2.700000. This ordinary text token estimate excludes cache, tools, retries and additional fees. It is not a complete bill or evidence of accepted requests.

Family pricing and calculator · Full catalog

Choose your next connection step

• Claude API pricing

  Use this dedicated guide to check claude api pricing before expanding the workload or changing request parameters.

• API429 quickstart

  Use this dedicated guide to check api429 quickstart before expanding the workload or changing request parameters.

First text request: curl, Python, JavaScript

1. Create a key in your API429 account and add balance by Russian bank card, a business invoice, USDT or TON. A $10 test balance is available for subscribing to the Telegram channel through the bonus bot.
2. Use the same key to verify claude-sonnet-5-5 in GET https://gateway.api429.com/v1/models.
3. Set API429_API_KEY on the server and send a small paid request. The example does not retry automatically.
4. Inspect HTTP status, finish_reason, text and actual usage. A timeout does not prove that the operation was unbilled.

The example uses only ordinary text Chat Completions with max_tokens=512. It does not verify native manufacturer methods, tools, reasoning, vision or manufacturer limits through API429. Python and JavaScript check key access before generation; check the model list separately for curl.

curl

curl --fail-with-body https://gateway.api429.com/v1/chat/completions \
  -H "Authorization: Bearer $API429_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"claude-sonnet-5-5","messages":[{"role":"user","content":"Explain the purpose of HTTP 429 in one sentence."}],"max_tokens":512,"stream":false}'

Python 3

import json
import os
import urllib.request

key = os.environ["API429_API_KEY"]
base = "https://gateway.api429.com/v1"
headers = {"Authorization": "Bearer " + key, "Content-Type": "application/json"}
models_request = urllib.request.Request(base + "/models", headers=headers)
with urllib.request.urlopen(models_request, timeout=30) as response:
    available = {item["id"] for item in json.load(response)["data"]}
model = "claude-sonnet-5-5"
if model not in available:
    raise ValueError("Model is unavailable to this key")
payload = json.loads("{\"model\":\"claude-sonnet-5-5\",\"messages\":[{\"role\":\"user\",\"content\":\"Explain the purpose of HTTP 429 in one sentence.\"}],\"max_tokens\":512,\"stream\":false}")
request = urllib.request.Request(base + "/chat/completions",
    data=json.dumps(payload).encode("utf-8"), headers=headers, method="POST")
with urllib.request.urlopen(request, timeout=60) as response:
    result = json.load(response)
choice = result["choices"][0]
if choice.get("finish_reason") != "stop" or not choice.get("message", {}).get("content"):
    raise ValueError("Incomplete or empty response")
print(choice["message"]["content"])
print(result.get("usage"))

JavaScript: Node.js 18+

const key = process.env.API429_API_KEY;
if (!key) throw new Error("Set API429_API_KEY");
const base = "https://gateway.api429.com/v1";
const headers = { Authorization: "Bearer " + key, "Content-Type": "application/json" };
const model = "claude-sonnet-5-5";
const available = await fetch(base + "/models", { headers, signal: AbortSignal.timeout(30000) });
if (!available.ok) throw new Error("Models HTTP " + available.status);
if (!(await available.json()).data.some(item => item.id === model)) throw new Error("Model unavailable to this key");
const response = await fetch(base + "/chat/completions", {
  method: "POST", headers, signal: AbortSignal.timeout(60000),
  body: JSON.stringify({"model":"claude-sonnet-5-5","messages":[{"role":"user","content":"Explain the purpose of HTTP 429 in one sentence."}],"max_tokens":512,"stream":false})
});
if (!response.ok) throw new Error("Generation HTTP " + response.status);
const result = await response.json();
const choice = result.choices?.[0];
if (choice?.finish_reason !== "stop" || !choice?.message?.content) throw new Error("Incomplete or empty response");
console.log(choice.message.content);
console.log(result.usage);

These examples do not prove access for your key; verify the exact ID before a paid request. API contract · Configure your client · Questions and support

Frequently asked questions

Sources and editorial review

Manufacturer documentation describes its family and its own API rules. API429 IDs, rates and request contracts require separate catalog and documentation checks. The original source-review date below is retained; English publication does not renew the source review.

• API429 public catalog
• API429 public request contract
• Anthropic documentation: models — opus 5 5 — overview
• Anthropic documentation: models — sonnet 5 5 — whats new sonnet 5 5
• Anthropic documentation: models — haiku 5 5 — overview
• Anthropic documentation: models — opus 5 5 — migration guide

Source review: Oct 24, 2026, 12:13 AM UTC. To connect, create an API429 account and follow the quickstart instructions.