Prepaid packs

Buy credits,
skip the x402 setup.

Register your wallet, send USDC on Base, and get a prepaid API key. No x402 client, no per-call wallet signing — just drop the key in your agent's headers and go.

Starter

$10

11.0 USDC credits (+10%)

~11 000 basic API calls
All 100 APIs unlocked
X-Klymax-Key auth
No expiry

Three steps to your API key.

Call /register with your Base wallet address. You get back your API key (klyx_xxx) instantly — before any payment.

Send USDC on Base

Send the pack amount in USDC on Base to the credits wallet below. The deposit is detected on-chain and your balance is credited automatically.

Call any API

Add X-Klymax-Key: klyx_xxx to any request. Credits are deducted per call based on the API's rate. Check balance anytime via /balance.

Step 1 — Register

Get your API key.

POST https://klymax402.com/register

# curl
curl -X POST https://klymax402.com/register \
  -H "Content-Type: application/json" \
  -d '{ "wallet": "0xYOUR_WALLET_ADDRESS" }'

# response
{
  "api_key":       "klyx_a1b2c3d4e5f6...",
  "balance_usdc":  0,
  "wallet":        "0xyour_wallet_address",
  "credits_bank":  "0x7cfEcBF575F0591772E09411FDBF1b88E4a0377E",
  "message":       "Registered. Send USDC to credits_bank to top up."
}

Step 2 — Fund

Send USDC to the credits wallet.

Credits bank wallet (Base mainnet)

0x7cfEcBF575F0591772E09411FDBF1b88E4a0377E

Send exactly the pack amount in USDC on Base. The deposit is detected on-chain and credited within a few minutes.
Send from the same wallet you registered in Step 1 — the system matches wallet address to API key.

Base mainnet · USDC (ERC-20) · eip155:8453

Check balance

Monitor your credits.

GET https://klymax402.com/balance

curl "https://klymax402.com/balance?key=klyx_a1b2c3d4e5f6..."

# response
{
  "balance_usdc":  11.0,
  "wallet":        "0xyour_wallet_address"
}

Step 3 — Call APIs

Use your key in any request.

POST any *.api.klymax402.com endpoint

# Token safety check — $0.003 deducted
curl -X POST https://token-safety-check.api.klymax402.com \
  -H "X-Klymax-Key: klyx_a1b2c3d4e5f6..." \
  -H "Content-Type: application/json" \
  -d '{ "token_address": "0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984" }'

# Web search — $0.003 deducted
curl -X POST https://web-search.api.klymax402.com \
  -H "X-Klymax-Key: klyx_a1b2c3d4e5f6..." \
  -H "Content-Type: application/json" \
  -d '{ "query": "x402 payment protocol" }'

# Response header includes remaining balance
X-Klymax-Balance: 10.997

MCP client config (Cursor / Windsurf)

{
  "mcpServers": {
    "klymax402": {
      "url": "https://app.ampersend.ai/api/hosted/klymax402/mighty-host/skill",
      "headers": { "X-Klymax-Key": "klyx_a1b2c3d4e5f6..." }
    }
  }
}

FAQ

Common questions.

How much is 1 credit?

1 credit = $0.001 USDC. An API at $0.003 deducts 3 credits per call. Utilities (QR code, UUID…) cost 1 credit; heavier APIs like phone validation cost up to 25 credits. See the pricing table for ranges per category.

Which USDC token should I send?

Send the official USDC on Base mainnet (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913). Do not send from another chain — credits will not be added.

How long does credit detection take?

Usually under 2 minutes after on-chain confirmation. If credits are not added after 10 minutes, contact support@klymax402.com with your tx hash.

Do credits expire?

No. Your balance persists indefinitely until fully consumed.

Can I top up an existing key?

Yes — just send another USDC transfer from your registered wallet. Credits are added to the same key automatically.

Prefer paying per call directly on-chain?

Use x402 mode — no registration, no prepay. Your agent's wallet pays per request. Back to the homepage for setup.