API reference

Base URL: https://layer-eight.vercel.app. All responses are JSON.

Authentication

Every endpoint except /v0/health needs a key from your dashboard:

authorization: Bearer lyr_your_key

x-api-key: lyr_your_key also works. Each key allows 60 requests per minute.

GET /v0/matches

Every live match, soonest event first. Use it to discover what Layer can answer.

Query	Default	Meaning
`limit`	`50`	1–200
`category`	all	e.g. `sports`, `economics`, `politics`, `crypto`

Response

Field	Meaning
`count`	Number of matches returned.
`matches[].kalshi`	The Kalshi market (see Market object).
`matches[].polymarket`	The Polymarket market.
`matches[].event_date`	The day the event happens (`YYYY-MM-DD`).
`matches[].category`	Layer's category for the event.
`matches[].confidence`	0–1. `1` when a person approved the match.
`matches[].basis`	`identical` or `equivalent_with_caveats`.
`matches[].caveats`	Which rules differ (see Overview).
`matches[].tier`	`human_verified` or `auto_verified`.

GET /v0/match

The twin of one market on the other venue.

Query	Required	Meaning
`venue`	yes	`kalshi` or `polymarket` — the venue of the id you pass.
`market_id`	yes	Kalshi: the market ticker. Polymarket: the `conditionId`, market slug, or numeric id.

Match found

Field	Meaning
`source_market`	The market you asked about.
`matched_market`	Its twin on the other venue.
`side`	Always `same`: YES on one pays like YES on the other.
`tier`, `confidence`, `basis`, `caveats`	As in `/v0/matches`.
`match_reason`	Who approved it and which outcomes were paired.
`checked_at`	When this answer was produced.

No match — matched_market is null and reason says why:

`reason`	Meaning
`not_indexed`	Layer doesn't know this id, or the market has closed.
`no_candidate`	Layer found nothing on the other venue that could be the same bet.
`pending_review`	A possible match exists but hasn't been approved yet.
`rejected`	A possible match was checked and is not the same bet.
`outcome_unmapped`	The events match, but this particular outcome has no twin.
`rules_changed_pending_review`	A venue edited its rules since approval; re-checking.
`specify_outcome`	This Polymarket market has two named sides; pass `<conditionId>:0` or `<conditionId>:1`.

Market object

Field	Meaning
`venue`	`kalshi` or `polymarket`.
`market_id`	The id to use with the venue's own API.
`group_id`	The venue's event id (Kalshi event ticker, Polymarket event slug).
`event`	The event's full title.
`question`	The market's own question.
`outcome`	The outcome this contract pays on.
`slug`, `yes_token_id`	Polymarket only: the market slug and the CLOB token id for YES — what you trade with.

GET /v0/health

No key needed. Is the API up and can it reach its database?

{
  "ok": true,
  "database": { "reachable": true, "ms": 62 },
  "venues": {
    "kalshi": { "open_events": 12587, "open_markets": 125458, "last_pull": "…" },
    "polymarket": { "open_events": 42935, "open_markets": 364647, "last_pull": "…" }
  },
  "live_market_pairs": 14
}

Errors

Status	`error`	When
400	`bad_request`	Missing or invalid query parameters.
401	`unauthorized`	No key, or the key is unknown or revoked.
429	`rate_limited`	Over 60 requests/minute. Wait `retry-after` seconds.
503	`database_not_configured` / `database_unreachable`	Layer can't reach its database.