Cross-venue equivalent-market pairs for arbitrage / relative-value spotting
Cross-venue equivalent-market pairs for arbitrage / relative-value spotting. We fuzzy-match open Polymarket vs Kalshi markets by title-token overlap and return candidate pairs with both venues' YES prices and the implied-probability spread (Polymarket YES minus Kalshi YES). Tune with minScore (0-1 title-similarity floor) and limit. Heuristic — a high score is a strong candidate, not a guaranteed identical contract. Read-only, keyless. No public source maps these directly; the pairing is derived by 2s.io.
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://2s.io/api/predict/matched-pairs
| Category | Market data |
|---|---|
| Provider host | 2s.io |
| Networks | eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-28 | valid payment request | 402 | $0.012 | 277 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"limit": 1,
"minScore": 0
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"properties": {
"method": {
"const": "GET"
},
"queryParams": {
"additionalProperties": false,
"properties": {
"limit": {
"description": "Max pairs (default 20).",
"maximum": 50,
"minimum": 1,
"type": "integer"
},
"minScore": {
"description": "Minimum title-similarity score 0-1 (default 0.3).",
"maximum": 1,
"minimum": 0,
"type": "number"
}
},
"type": "object"
},
"type": {
"const": "http"
}
},
"required": [
"type",
"method",
"queryParams"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}