# RankFuel

> Provably-fair leaderboards for apps, games, communities, and AI agents. Cryptographic proof that standings are honest. One API. One MCP server.

RankFuel is the leaderboard and ranking-settlement layer of the Rewards Fuel incentive stack.
Stack chain: **RankFuel** (who's winning) → **Rewards Fuel** (what they win) → **RFWIN** (who provably gets it).

## Products

- [RankFuel Leaderboards](https://rnkfl.com): Provably-fair leaderboard API with commit-reveal + drand quicknet. Edge-native, globally distributed infrastructure.
- [Rewards Fuel Contests](https://rewardsfuel.com): Contest and sweepstakes engine for prizes and growth.
- [RFWIN](https://rewardsfuel.com): Provably-fair winner selection with drand + public verification certificates.

## Pages

- [Home](https://rnkfl.com/): Overview, features, and use cases
- [Pricing](https://rnkfl.com/pricing): Stack pricing for all three products — free plan + 3 paid tiers
- [Live Demos](https://rnkfl.com/demos): Live sport leaderboard demos (golf, basketball, baseball, and more)
- [Templates](https://rnkfl.com/templates): Sport and competition leaderboard templates
- [MCP Documentation](https://rnkfl.com/mcp): Model Context Protocol integration — tools for AI agents

## API

- Base URL: `https://api.rnkfl.com`
- REST: `POST /v1/leaderboards/{id}/scores` — submit scores (idempotent, requires Idempotency-Key header)
- REST: `GET /v1/leaderboards/{id}/standings` — read current standings
- REST: `GET /v1/leaderboards/{id}/proof` — download verifiable proof bundle
- MCP: `https://api.rnkfl.com/mcp` — native MCP server for agents

## MCP Tools (for AI agents)

- `submit_score` — post a score for a subject in a leaderboard
- `get_standings` — read current rankings
- `verify_ranking` — verify that standings match the cryptographic proof
- `open_period` — start a new competition period
- `settle_period` — lock standings to a future drand round and publish proof

## Authentication

All API calls require `Authorization: Bearer $RANKFUEL_KEY`. Keys issued at https://app.rewardsfuel.com/rankfuel.

## Pricing

- Free: 3 leaderboards, 10k score writes/mo, public proofs
- Marketing Master: $13.95/mo (or $139.50/yr) — 10 boards, 100k writes, all themes + appearance
- Promoter: $19.95/mo (or $199.50/yr) — 25 boards, 500k writes, MCP server
- Promoter Pro: $29.95/mo (or $299.50/yr) — unlimited boards, 2M writes, settlement rails

Annual billing saves 2 months (10 months charged for 12 months of service).

## Key Facts for Agents

- Provably fair: commit-reveal scheme using drand quicknet round for seed derivation
- `verify_ranking` takes a leaderboard ID and period; returns pass/fail + proof details
- Idempotent score writes: always include `Idempotency-Key: <uuid>` to avoid double-posting
- Multi-tenant: each API key is scoped to a single account; no cross-account reads
- Response envelope: `{ "ok": bool, "data": ..., "error": null | { "code": string, "message": string } }`
- Sport template labels describe categories only — not affiliations with leagues, teams, or third-party brands.
- Cryptographic verification supports auditability; customers remain responsible for competition rules and legal compliance.