Any model. One key, or none.

curl https://ask.singitai.app/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{"model": "free/deepseek-v4.1-flash",
       "messages": [{"role": "user", "content": "Hello!"}]}'

from openai import OpenAI

# The official OpenAI SDK, pointed at SingIt, with a key from the SingIt app.
client = OpenAI(base_url="https://app.singitai.app/v1", api_key="sk_singit_...")
answer = client.chat.completions.create(
    model="claude-opus-5.5",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(answer.choices[0].message.content)

# Your SingIt key, in Anthropic's format
export ANTHROPIC_BASE_URL="https://app.singitai.app"
export ANTHROPIC_AUTH_TOKEN="sk_singit_..."
export ANTHROPIC_MODEL="claude-sonnet-5.5"
claude

# Claude Code. The free tools work without the header; paid ones need your key.
claude mcp add --transport http singit https://app.singitai.app/mcp \
  --header "Authorization: Bearer sk_singit_..."

# Cursor and other clients: mcp.json
{
  "mcpServers": {
    "singit": {
      "url": "https://app.singitai.app/mcp",
      "headers": { "Authorization": "Bearer ${env:SINGIT_API_KEY}" }
    }
  }
}

import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { UptoEvmScheme } from "@x402/evm/upto/client";
import { createPublicClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { base } from "viem/chains";

// A wallet holding a little USDC on Base. No ETH: the facilitator pays the gas.
const account = privateKeyToAccount(process.env.AGENT_KEY);
const chain = createPublicClient({ chain: base, transport: http() });
const client = x402Client.fromConfig({ schemes: [{ network: "eip155:8453",
  client: new UptoEvmScheme({ address: account.address, signTypedData: account.signTypedData,
                              readContract: chain.readContract.bind(chain) }) }] });
const pay = wrapFetchWithPayment(fetch, client);

const res = await pay("https://ask.singitai.app/v1/chat/completions", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ model: "claude-opus-5.5",
                         messages: [{ role: "user", content: "Hello!" }] }),
});
const answer = await res.json();
console.log(answer.choices[0].message.content, answer.billing.totalAtomic);

# 1. Ask with no payment: HTTP 402 and a PAYMENT-REQUIRED header (base64 JSON, x402 v2)
curl -i https://ask.singitai.app/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{"model":"deepseek-v4.1-flash","max_tokens":200,"messages":[{"role":"user","content":"Hello"}]}'

# 2. Sign an offer: upto on Base comes first, a ceiling of 0.0015 USDC here, no ETH needed.
#    The "x402 · no key" tab signs it for you; so do Coinbase's Bazaar MCP and agentic wallet.
# 3. Retry with PAYMENT-SIGNATURE: HTTP 200 with choices[0].message.content,
#    billing.totalAtomic (what was settled) and a PAYMENT-RESPONSE header.

# Models, our prices, list prices and fees
GET https://ask.singitai.app/v1/models

# OpenAPI 3.1 with x402 payment info (x402scan reads this)
GET https://ask.singitai.app/openapi.json

# x402 resource list
GET https://ask.singitai.app/.well-known/x402

# LangChain.js — MCP tools and x402-paid chat
npm install @langchain/mcp-adapters @langchain/core @langchain/openai

# Vercel AI SDK — MCP tools and x402-paid chat
npm install ai @ai-sdk/mcp @ai-sdk/openai-compatible

# ElizaOS — plugin, not on npm yet: install from a checkout
git clone https://github.com/SingItAi/SingItAI.git
npm install ./SingItAI/integrations/elizaos-plugin