# Demandex API

Demandex mines community demand for physical products. 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 with verbatim evidence and permalinks, and answers ad-hoc demand verdicts for any query. A free honest sample and a free category index let an agent learn the shapes before paying; paid tiers return trending teasers, category lists, full evidence cards, and demand verdicts (7-day cached or live research). Physical products only. Evidence is quoted public Reddit posts with provenance (subreddit, upvotes, permalink). Informational only — not a guarantee of any business outcome.

- **Base URL**: https://api.demandex.dev
- **Docs (agent-facing)**: https://api.demandex.dev/llms.txt · https://api.demandex.dev/llms-full.txt
- **OpenAPI 3.1**: https://api.demandex.dev/openapi.json
- **Discovery (JSON)**: https://api.demandex.dev/discovery
- **x402 manifest**: https://api.demandex.dev/.well-known/x402
- **Agent card (A2A)**: https://api.demandex.dev/.well-known/agent-card.json
- **Terms**: https://api.demandex.dev/terms.txt

## Free (no auth, no payment)

| Method | Path | What |
|--------|------|------|
| GET | /health | Liveness + payment mode |
| GET | /v1/categories | Free, no payment. Returns the category index — every active category with its opportunity count, top opportunity score, and last-updated time. A cheap change-detection funnel an agent can poll to learn which categories to buy into. Shape: { categories: [{ slug, opportunityCount, topScore, lastUpdated }], generatedAt }. (rate limit 30/min) |
| GET | /v1/sample/opportunity | Free, no payment. Returns one REAL, fixed sample opportunity card in the SAME full shape as the paid GET /v1/opportunity — all score components, productAngle, summary, and verbatim evidence — plus { sample: true, note, cardAsOf }. It is a stable teaching sample (real data) so an agent can learn the exact card shape before paying. Returns 503 corpus_warming only while the index is empty (no cards mined yet). (rate limit 10/min) |
| GET | /terms.txt · /terms.json | Terms of Service |

## Paid (x402 V2 — USDC on eip155:8453, per-call)

| Method | Path | Price | What |
|--------|------|-------|------|
| GET | /v1/opportunities/trending | $0.01 | Paid ($0.01 USDC via x402). Returns the top 20 active opportunity cards by score as TEASERS — { id, slug, title, category, score, signalCount, lastSeen } only. No evidence and no productAngle (buy GET /v1/opportunity for the full card). While the index is still warming and no active cards exist yet, you get a no-charge 503 corpus_warming (never an empty charged list) — poll the free GET /v1/categories to see when cards go live. Compute-first / settle-after — you are not charged on any error. Response carries fetchedAt. |
| GET | /v1/opportunities | $0.02 | Paid ($0.02 USDC via x402). Returns up to 50 active opportunity cards in a category, each as a teaser ({ id, slug, title, category, score, signalCount, lastSeen }) plus its summary. Requires ?category=; ?minScore= optionally filters. A missing or unknown category returns a no-charge 400 that lists the valid categories; a valid category with no active cards yet (index still warming) returns a no-charge 503 corpus_warming instead of an empty charged list. Compute-first / settle-after — you are not charged on any error. Response carries fetchedAt. |
| GET | /v1/opportunity | $0.05 | Paid ($0.05 USDC via x402). Returns one full opportunity card by ?id= or ?slug= (exactly one required, else a no-charge 400): all score components (freqScore, intensityScore, wtpScore), productAngle, summary, evidence[] (verbatim quotes with subreddit, upvotes, permalink), builderMomentum, firstSeen, lastSeen, signalCount, distinctAuthors. Compute-first / settle-after — you are not charged when the id/slug is missing, ambiguous, or not found. Response carries fetchedAt. |
| POST | /v1/gauge | $0.03 | Paid ($0.03 USDC via x402). POST { "query": "...", "category"?: "..." } to get a demand verdict for any physical-product query. Answers are cached 7 days by normalized query; on a cache miss Demandex matches the query against the mined corpus (signals and cards by keyword) and runs one LLM synthesis call. query must be 3..200 chars. Reads the JSON body first, falling back to ?query=. Verdict shape: { 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. If the LLM is unavailable you get a 503 and are not charged. Compute-first / settle-after. |
| POST | /v1/gauge/live | $0.1 | Paid ($0.10 USDC via x402). Same body as /v1/gauge — POST { "query": "...", "category"?: "..." } (query 3..200 chars; body-first, ?query= fallback). Combines the mined corpus with a LIVE Reddit search run at request time (up to 50 posts, subreddits unrestricted) and one LLM synthesis call. Total compute budget is 45 seconds; on timeout you get a 504 and are not charged. Returns the same verdict shape as /v1/gauge (cache is always miss). A zero-match, empty-search query is a real cold verdict (chargeable), not an error. If the LLM is unavailable you get a 503 and are not charged. Compute-first / settle-after. |

Prices are USD, settled as USDC (6 decimals). Compute-first / settle-after: you are never
charged for errors.

## Quickstart — pay per call (x402, USDC)

```
# 1) Call a paid route with no payment → 402 challenge
curl -s "https://api.demandex.dev/v1/opportunities/trending"
# → { "x402Version": 2, "accepts": [ { "scheme": "exact", "network": "…", "asset": "USDC",
#     "price": "$0.01", "payTo": "…" }, … ] }

# 2) Sign an x402 'exact' USDC authorization for one 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 }
```

## Links
- Docs: https://api.demandex.dev/llms.txt
- Full: https://api.demandex.dev/llms-full.txt
- OpenAPI: https://api.demandex.dev/openapi.json
- Discovery: https://api.demandex.dev/discovery
- Agent card: https://api.demandex.dev/.well-known/agent-card.json
- Changelog: https://api.demandex.dev/changelog