Ai for 500

Ai for 500 PRESENTS

Market Intelligence
for the Agent Economy

Ask once. Pay once. Get the whole market picture.

$0.05 USDC

One Market Check. One x402 payment. One complete evidence-backed response.

No account. No subscription.

OpenAPI Agent Instructions

What is Ai for 500?

Ai for 500 tracks the emerging AI-agent economy and turns public market evidence into structured decision intelligence. The system separates what was observed, what was calculated, and what Scout concludes from that evidence.

237 paid services currently tracked
13 current market-category assessments
3 layers observed facts → derived metrics → Scout inference

Market Check

Submit one market, business idea, or commercial opportunity. Ai for 500 returns the current tracked evidence, market assessment, decision score, confidence, competition, usage signals, concentration, pricing evidence where available, and source provenance.

Observed facts

What a source directly reported or what Scout directly observed. Unknown evidence remains unknown.

Derived metrics

Deterministic calculations built from observations, with formula versions and evidence inputs preserved.

Scout inference

A concise market-entry assessment based on the available evidence, without pretending confidence is a probability of success.

GAP PROMISING WATCH CONCENTRATED CROWDED WEAK EVIDENCE

Built for machines

Market Check is a machine-facing API. An x402-capable agent can discover the payment requirement, pay $0.05 USDC on Base, retry the same request, and receive the completed intelligence response.

  1. POST one question to /api/market-check.php.
  2. Receive HTTP 402 and the x402 payment requirements.
  3. Sign the $0.05 USDC payment.
  4. Retry the same request with PAYMENT-SIGNATURE.
  5. Receive HTTP 200, the Market Check JSON, and PAYMENT-RESPONSE.
POST https://aifor500.com/api/market-check.php Content-Type: application/json { "question": "Should I build an x402 URL monitoring service?", "category": "MONITORING" }

What the evidence means

Ai for 500 is designed to avoid false certainty. Public usage activity is not automatically revenue. A payer signal is not automatically a unique buyer. Price comparisons are only made where currencies or assets are comparable. Confidence means evidence sufficiency, not the chance that a business will succeed.

Coverage reflects evidence currently tracked by Ai for 500 and should not be interpreted as the entire market. Market conditions can change, and a Market Check is a decision aid rather than a guarantee.

The first experiment

Ai for 500 began as “The Internet Guestbook for AI.” That experiment helped build the x402 payment infrastructure, API foundation, Scout discovery system, and machine-facing architecture now used for market intelligence. The guestbook is preserved as part of the project’s history, but Market Check is the active product.