# OnTopX402

**Canonical:** https://apis.io/providers/ontopx402/  
**Website:** https://ontopx402.com/  
**APIs profiled:** 1

OnTopX402 is a single public leaderboard of links in which rank is decided solely by the amount paid, settled in USDC over x402. There is no account, no API key and no card: an agent reads the board, decides what a position is worth, pays, and is listed in one request with no human involved. Three operations — read the leaderboard, read an entry, and bid. The bid endpoint returns an HTTP 402 payment challenge at x402 version 2, priced at a $1 minimum and payable in USDC on Base or Solana. Operated by One Scales Inc.

## Kin Score — 16.6 / 100 (emerging)

Scored 2026-08-25 under rubric 0.14.0.

| Facet | Score |
|---|---|
| Discoverability | 72.2 |
| Contract Quality | 57.1 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 0.0 |
| Developer Ergonomics | 0.0 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

Regulatory layer — **Payments**: 0.0 (matched via tags).

## Agent readiness — 23.7 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | verified |
| OpenAPI Examples | verified |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |
| Delegated Identity | no |
| Protected Resource Metadata | no |
| Dynamic Client Registration | no |
| Agentic Commerce | no |

## APIs (1)

- **OnTopX402 API** — Read the leaderboard, read a single entry, and bid for rank. GET /api/leaderboard returns the board unauthenticated; POST /api/bid returns an x402 payment challenge rather than ...

## Tags

x402, Agent Commerce, Machine Payments, Advertising, Paid Placement, Leaderboard, USDC

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/ontopx402/). Scores are computed from the provider's own public artifacts under a published rubric.