aid: ontopx402
name: OnTopX402
description: >-
  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.
type: Index
url: https://raw.githubusercontent.com/api-evangelist/ontopx402/refs/heads/main/apis.yml
created: '2026-08-24'
modified: '2026-08-24'
specificationVersion: '0.23'
tags:
- x402
- Agent Commerce
- Machine Payments
- Advertising
- Paid Placement
- Leaderboard
- USDC
tags_raw:
- x402
- usdc
- agent-payments
- paid-placement
- leaderboard
apis:
- aid: ontopx402:ontopx402-api
  name: OnTopX402 API
  description: >-
    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 requiring
    an account.
  humanURL: https://ontopx402.com/
  baseURL: https://ontopx402.com
  tags:
  - x402
  - Agent Commerce
  - Advertising
  properties:
  - type: OpenAPI
    url: openapi/ontopx402-api-openapi.yml
  - type: APIReference
    url: https://ontopx402.com/openapi.json
  - type: Documentation
    url: https://ontopx402.com/
  - type: FinOps
    url: finops/ontopx402-x402-challenge.json
  - type: Examples
    url: examples/ontopx402-leaderboard-example.json
common:
- type: LLMsTxt
  url: llms/ontopx402-llms.txt
- type: Website
  url: https://ontopx402.com/
- type: FinOps
  url: finops/ontopx402-x402-challenge.json
maintainers:
- FN: One Scales Inc.
  email: info@ontopx402.com
  url: https://ontopx402.com/
x-provenance:
  added: '2026-08-24'
  method: searched
  source: https://ontopx402.com/llms.txt
  note: >-
    Submitted via apis.io/add on 2026-08-24 and auto-published by the gate at rating 48. The
    submitted APIs.json URL returns 404 against a control that also 404s, so it is a bad pointer
    in the submission rather than an absent surface. Everything here was found from the provider's
    own llms.txt and OpenAPI.
    The x402 surface is real and was exercised. POST /api/bid with no payment header returns HTTP
    402 carrying x402Version 2, a `payment-required` header, and two `accepts` entries: USDC on
    Base (eip155:8453) and on Solana, both at amount 1000000 (a $1 minimum), 300-second timeout.
    The challenge also carries a `bazaar` extension with full JSON Schema for the request body and
    an example response — an unusually complete machine-readable purchase contract. The saved
    file under finops/ is that response verbatim. GET /api/leaderboard returns the live board
    unauthenticated and is saved under examples/.
    WHAT THIS SERVICE IS, STATED PLAINLY, BECAUSE IT BEARS ON WHETHER WE SHOULD CARRY IT. This is
    paid placement. The provider says so itself: "Rank is decided by the amount paid, and nothing
    else… There is no editorial judgement, no quality score, no review… This is paid placement,
    and it says so plainly. Listing links are followed." Its own tags include backlink, seo,
    sponsored and paid-placement. It is honest, working, and technically excellent — and it is
    also a followed-backlink product, which is the category API Evangelist refuses when it arrives
    by email. Listed here on the standing rule that a valid company with a real API gets listed
    and the rating speaks; flagged for a policy decision rather than decided unilaterally.