Marketplace and Discovery

The OpenDexter marketplace is where paid x402 APIs become findable. Resources enter the catalog through three paths: sellers deploying endpoints with the x402 SDK, the bazaar crawler indexing external facilitators (Coinbase, PayAI, Ultraviolet) every two hours, and direct registration via the facilitator settlement hook.

How Resources Get Discovered

Every x402 payment that settles through the Dexter facilitator automatically registers the resource URL in the catalog. The system:

1. Normalizes the URL and deduplicates against existing entries
2. Sets discovery_status to pending
3. Queues it for AI verification (runs every 15 minutes, up to 50 resources per batch)
4. If the verification score is 75+, the resource is auto-approved and appears in search results

Resources that score below 50 get flagged for review. Resources already approved that regress below 50 are flagged too.

Browsing the Marketplace

Web UI at dexter.cash/opendexter — browse, search, filter by category, chain, price, and verification status. Each listing shows:

• Resource name, description, and category
• Price per request (USDC)
• Verification grade (A+ through F, based on a 0-100 quality score)
• Total settlements, volume, and last activity
• Seller profile with reputation score
• Refund protection status (based on verification score)

Via agents using the x402_search MCP tool:

x402_search(query: "DeFi", network: "solana", category: "trading")

Returns matching resources with pricing, chain support, and quality scores.

Verification Grades

Every resource gets a letter grade based on its AI verification score:

The AI verifier (running gpt-5.2-codex) probes each endpoint by making a real request. For endpoints costing $0.25 or less, it pays and evaluates the response against five criteria:

1. Did the endpoint answer the specific request?
2. Is the response specific and actionable (not generic)?
3. Would a paying user be satisfied with this?
4. Are there red flags (errors, empty responses, prompt-for-clarification when input was specific)?
5. Response size (penalizes responses over 30KB, flags "context bombs" over 50KB)

Resources are re-verified every 24 hours, or every 12 hours for high-traffic endpoints (100+ settlements).

Marketplace Ranking

Search results are ranked by a composite score that weights:

• Trust (28 points for passing verification)
• Quality (score × 0.55, boosted by usage)
• Usage (logarithmic volume scaling)
• Discovery boost (bonus for new high-quality, low-volume resources)
• Freshness (recent settlements and verification boost rank)
• Reputation (ERC-8004 on-chain reputation score)
• Price (slight preference for lower-cost resources)
• Reliability (penalty for consecutive verification failures)

Results are then diversified so the top 24 don't cluster by category or seller.

API Access

Query the marketplace programmatically:

curl "https://api.dexter.cash/api/facilitator/marketplace/resources?search=defi&verified=true&sort=quality_score&limit=10"

Available query parameters: search, category, seller, network, verified, maxPrice, sort (volume, settlements, recent, quality_score, relevance, marketplace), limit, offset.