Swap USDC for BALD tokens on Base via a pay-per-call x402 endpoint
What it does
This x402 endpoint at bald.x420.dev lets callers purchase BALD tokens (contract 0x110B4ef11db22eEb3caFCB53a58b8B6B1bCDEb07) on the Base network by paying with USDC. The endpoint accepts a POST request with an optional `amount` field specifying how much USDC to spend (defaults to 5 USDC if omitted). Payment is handled via the x402 protocol: callers attach an X-PAYMENT header with a valid payment proof, and the service executes a token swap on their behalf, returning the swap transaction hash, send transaction hash, tokens received, and USDC amount paid.
The maximum payment accepted per call is 5 USDC (maxAmountRequired: 5000000 in 6-decimal USDC units), paid to address 0x93109d14F6665a9c9675290D3cD5A6c07bBAfdbd. The token was created via Clanker and is viewable on clanker.world. The hosting platform x420.dev appears to provide per-token subdomains with x402-enabled swap endpoints. No additional documentation, OpenAPI spec, or pricing page exists beyond the landing page and the x402 challenge itself.
Capabilities
Use cases
- —Programmatically purchasing BALD tokens with USDC on Base without needing a wallet UI
- —AI agents autonomously acquiring meme/community tokens via x402 micropayments
- —Automating periodic token buys of a specific Clanker-deployed token
Fit
Best for
- —Agents or scripts that need to buy BALD tokens hands-free via HTTP
- —Developers experimenting with x402 payment-gated DeFi actions
- —Automated portfolio strategies involving Clanker-launched tokens on Base
Not for
- —Purchasing tokens other than BALD (this endpoint is single-token specific)
- —Swaps exceeding 5 USDC per transaction
- —Users who need detailed swap routing or slippage controls
Quick start
curl -X POST https://bald.x420.dev/api/puff-custom \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{"amount": "2.5"}'Example
Request
{
"amount": "2.5"
}Response
{
"message": "Successfully swapped USDC for BALD tokens",
"tokensReceived": "150000.0",
"usdcAmountPaid": "2.5",
"sendTransactionHash": "0x789abc...012def",
"swapTransactionHash": "0xabc123...def456"
}Endpoint
Quality
The x402 challenge is live and includes a well-defined outputSchema with input/output fields, giving clear integration guidance. However, there is no OpenAPI spec, no documentation pages (all return 'doesn't exist'), and no pricing or usage details beyond the challenge itself. The response example is inferred from the outputSchema rather than observed.
Warnings
- —No documentation pages exist — /docs, /api, /pricing, and /README all return placeholder 'doesn't exist' pages
- —Response example is inferred from the outputSchema, not from an actual observed response
- —This endpoint facilitates cryptocurrency token purchases — regulatory considerations may apply
- —Max amount per call is 5 USDC; larger purchases would require multiple calls
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 5000000 (5 USDC) on the Base networkhttps://bald.x420.dev/api/puff-custom
- —BALD token contract address is 0x110B4ef11db22eEb3caFCB53a58b8B6B1bCDEb07https://bald.x420.dev
- —The token was created via Clanker and is viewable on clanker.worldhttps://bald.x420.dev
- —Payment is sent to address 0x93109d14F6665a9c9675290D3cD5A6c07bBAfdbd using USDC asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://bald.x420.dev/api/puff-custom
- —The amount field defaults to 5 USDC if not providedhttps://bald.x420.dev/api/puff-custom