x4PayAPI Market

PromptShield

Pay-per-request content gate for AI agents. 0.002 USDC on Base via x402. @grindfreelabs / rob@grindfree.net

1 route settlement-verified · $0.002 USDC/request · 1 endpoint · Verification · base network · x402 protocol

Verified routes

Other routes are unverified.

Networks: Base (settlement-verified)

Discovery is free. Agents search the catalogue here. Payment happens on the listing 402, not on PayAPI.

url https://payapi.market/mcp

Listing facts

Provider
PromptShield
Hosted at
promptshield.grindfree.net
Category
Verification
Price
$0.002 USDC per request
Payment networks
Base
Settlement-verified
1 route, last checked 2026-11-06
Listed on PayAPI Market
2026-11-06

Try PromptShield

Call a verified route without paying first. The server should answer HTTP 402 Payment Required with the price, the USDC asset, the network and the wallet to pay. An x402 client pays that amount on Base and retries with the payment header.

curl -i -X POST "https://promptshield.grindfree.net/v1/screen"

About this API

PromptShield is listed in the Verification category with pricing at $0.002 USDC/request. One route has been settlement-verified by PayAPI Market on 2026-11-06. View receipt on Basescan.

Payments settle on base in USDC via the x402 protocol. AI agents discover this API through the PayAPI Market MCP server and pay per request without API keys or accounts.

This API exposes 1 endpoint.

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Paste this on your site. The link points at this listing. Listing is free and providers keep 100%.

Settlement-verified on PayAPI Market

Markdown

[![Settlement-verified on PayAPI Market](https://payapi.market/badge/promptshield.svg)](https://payapi.market/api/promptshield)

HTML

<a href="https://payapi.market/api/promptshield"><img src="https://payapi.market/badge/promptshield.svg" alt="Settlement-verified on PayAPI Market" height="20"></a>

What this badge means

Questions about this API

What does PromptShield do?

Pay-per-request content gate for AI agents. 0.002 USDC on Base via x402. @grindfreelabs / rob@grindfree.net It is provided by PromptShield.

How much does PromptShield cost?

PromptShield is priced at $0.002 USDC per request, paid per call with no subscription. Verified with a $0.002 test payment on 6 Nov 2026. The exact amount for each call is in the HTTP 402 response before any money moves.

Do I need an API key or account to use PromptShield?

No. PromptShield uses the x402 protocol, so an agent pays per request in USDC on Base and gets the response, with no API key, account or signup.

Has PromptShield been verified?

Yes, 1 route. PayAPI Market paid for a real call from its own wallet, received real data back and recorded the USDC settlement on-chain, most recently on 2026-11-06.

How does an AI agent find PromptShield?

Through the free PayAPI Market MCP server at https://payapi.market/mcp, using search_apis or get_api, or over plain HTTP at https://payapi.market/agent/search. Discovery is free; the agent pays the provider directly on the listing's own 402.

More Verification APIs · Browse the marketplace · List your own API

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