Demandex

E-commerce demand intelligence for AI agents — the index of what people want next. Mines Reddit complaint/intent posts across ~70 communities into scored opportunity cards with verbatim evidence and permalinks, and answers ad-hoc demand verdicts for any physical-product query (7-day cached or live research). Pay-per-call via x402 (USDC on Base); no accounts, no keys. Free GET /v1/categories and GET /v1/sample/opportunity return the response shapes before you pay. Physical products only.

Demandex — E-commerce Demand Intelligence for AI Agents

API at https://api.demandex.dev. Demandex is the index of what people want next: it classifies Reddit complaint and intent posts across ~70 communities into demand signals (replacement-part hunts, unmet needs, willingness-to-pay, repeat failures), clusters them into scored opportunity cards (0-100 = frequency × intensity × willingness-to-pay) with verbatim evidence and permalinks, and answers ad-hoc demand verdicts for any query. Strictly pay-per-call via x402 — no accounts, no API keys, no bundles. Compute-first / settle-after: you are never charged for an error or an empty result.

Physical products only. Evidence is quoted from public Reddit posts with provenance (subreddit, upvotes, permalink). Informational only — not a guarantee of any business outcome.

Check the active payment mode any time at GET /health (live|mock).

Free endpoints (no auth, no payment)

Use these to learn the response shapes before paying.

Method	Path	Description
GET	/health	Liveness + configured payment mode (live|mock)
GET	/v1/categories	FREE category index — every active category with opportunityCount, topScore, lastUpdated. A cheap change-detection funnel to poll (30/min).
GET	/v1/sample/opportunity	FREE fixed sample opportunity card — one REAL card in the SAME full shape as the paid /v1/opportunity (all score components, productAngle, summary, verbatim evidence) plus { sample: true, note, cardAsOf } (10/min).
GET	/terms.txt · /terms.json	Terms of Service (also sets X-Terms-URL)
GET	/changelog	Human-readable changelog (markdown)

bash

curl https://api.demandex.dev/v1/categories
curl https://api.demandex.dev/v1/sample/opportunity

The free sample is the fastest way to learn the full card shape: it returns the same fields a paid /v1/opportunity returns, so an agent can wire up parsing for free, then spend on live cards.

Paid endpoints (x402 V2, USDC on Base, per-call)

Each paid call is a flat price per call, paid via x402. Compute-first / settle-after — you are not charged on any error, and never for an empty result (a still-warming index returns a no-charge 503 corpus_warming).

Method	Path	Price	Description
GET	/v1/opportunities/trending	$0.01	Top 20 active opportunity cards by score as TEASERS (id, slug, title, category, score, signalCount, lastSeen). No evidence — buy /v1/opportunity for the full card.
GET	/v1/opportunities?category=SLUG	$0.02	Up to 50 active cards in a category, each a teaser + summary. Requires ?category=; optional ?minScore= (0-100). Unknown/missing category → no-charge 400 listing valid categories.
GET	/v1/opportunity?id=ID | ?slug=SLUG	$0.05	One FULL opportunity card: all score components (freqScore, intensityScore, wtpScore), productAngle, summary, evidence[] (verbatim quotes with subreddit, upvotes, permalink), builderMomentum, firstSeen/lastSeen, signalCount, distinctAuthors. Exactly one of id|slug (else no-charge 400); not found → no-charge 404.
POST	/v1/gauge	$0.03	Demand verdict for any physical-product query, cached 7 days by normalized query (corpus-only synthesis + 1 LLM call).
POST	/v1/gauge/live	$0.10	Same as /v1/gauge but combines the mined corpus with a LIVE Reddit search at request time (up to 50 posts) + LLM synthesis, under a 45s budget (timeout → no-charge 504). Never a cache hit.

Prices are USD, settled as USDC (6 decimals). The verdict shape (both gauges): { query, verdictScore (0-100), demandTemperature (cold|warm|hot), rationale, topEvidence[] (≤5, each { quote, permalink, upvotes }), relatedOpportunities[] (≤5, each { slug, score }), cache (hit|miss), fetchedAt }. A zero-match query is a real cold verdict (chargeable), not an error.

Gauge request bodies

bash

# Cached demand verdict ($0.03)
curl -X POST https://api.demandex.dev/v1/gauge \
  -H "Content-Type: application/json" \
  -d '{"query":"sony xm5 replacement headband","category":"headphones"}'

# Live-research demand verdict ($0.10) — same body, fresh Reddit search at request time
curl -X POST https://api.demandex.dev/v1/gauge/live \
  -H "Content-Type: application/json" \
  -d '{"query":"sony xm5 replacement headband"}'

query is required (3..200 chars); category is optional (scopes the corpus match). The body is read first, falling back to ?query=.

Paying (x402) — first call

Every paid route follows the standard x402 challenge → pay → retry flow. Try every response shape for free first via /v1/categories and /v1/sample/opportunity.

bash

# 1) Call a paid route with no payment → 402 challenge (you are not charged)
curl -s "https://api.demandex.dev/v1/opportunities/trending"
# → { "x402Version": 2, "accepts": [ { "scheme": "exact", "network": "eip155:8453",
#     "asset": "USDC", "price": "$0.01", "payTo": "…" }, … ] }

# 2) Sign an x402 'exact' USDC authorization for the Base accepts[] rail, then retry.
#    Standard @x402 V2 clients send PAYMENT-SIGNATURE; legacy clients send X-PAYMENT.
curl -s "https://api.demandex.dev/v1/opportunities/trending" -H "PAYMENT-SIGNATURE: <payload>"
# → 200 { …, "charged": true }

Free-funnel guidance

Start on the free plane to learn Demandex for zero cost, then spend only where it pays:

1. GET /v1/categories — poll this to see which categories have live opportunity cards and how fresh they are (lastUpdated, topScore). Cheap change-detection.
2. GET /v1/sample/opportunity — wire up your full-card parser here for free; it is the same shape as the paid /v1/opportunity.
3. Then buy: /v1/opportunities/trending ($0.01) to browse, /v1/opportunities?category= ($0.02) to drill into a category, /v1/opportunity?slug= ($0.05) for full evidence, and /v1/gauge ($0.03) / /v1/gauge/live ($0.10) for ad-hoc verdicts.

Machine discovery

Path	What
/llms.txt	This doc (concise)
/llms-full.txt	Extended agent doc
/openapi.json	OpenAPI 3.1 spec
/discovery	Discovery JSON (free/paid endpoint listing)
/.well-known/x402	x402 payment manifest
/.well-known/agent-card.json	A2A agent card
/changelog	Changelog (markdown)

Errors & caveats

• 400 — bad params (missing/unknown category; missing/ambiguous id/slug; query outside 3..200 chars). You were NOT charged.
• 402 — payment required / verification or settlement failed (you were NOT charged).
• 404 — requested opportunity not found (you were NOT charged).
• 503 corpus_warming — the index is still building; no cards to return yet (you were NOT charged).
• 503 — LLM synthesis temporarily unavailable on a gauge call (you were NOT charged).
• 504 — /v1/gauge/live exceeded its 45s research budget (you were NOT charged).

Disclaimer: Demand intelligence aggregated from public Reddit posts; physical products only; informational, not professional or business advice; provided as-is. Evidence reflects the mined corpus at fetch time. Terms: https://api.demandex.dev/terms.txt