Leads

A lead is a pair of contracts that, because of a proven relation, pays at least $1 whatever happens. This page covers which legs a relation allows, every field a lead reports, how fees and order-book depth are estimated, and what each limited_by value means. You need it when reading GET /v1/opportunities, the leads stream topic or the lead.executable webhook. Leads are observations from the latest graph run, not quotes: prices move between the run and your order.

The idea

If “49ers over 10.5 points” implies “49ers over 3.5 points”, then buying No on the first and Yes on the second pays $1 in every score:

49ers score	No on over 10.5	Yes on over 3.5	Pays
0 to 3	$1	$0	$1
4 to 10	$1	$1	$2
11 or more	$0	$1	$1

At 5¢ and 90¢ the pair costs 95¢ for a guaranteed $1. The 5¢ left over, less fees, is the edge.

Which legs a relation allows

Relation (left side)	Buy	Why it pays
`subset` (left implies right)	left No, right Yes	Either the left is No, or the right is Yes.
`superset` (right implies left)	left Yes, right No	Either the right is No, or the left is Yes.
`contradicts`	left No, right No	At most one can be Yes, so at least one No pays.
`equivalent`	left Yes and right No, or left No and right Yes	Both leads exist; each pays exactly $1.
`overlaps`	nothing	No implication runs either way.

A lead is kept only when the two asks together cost less than $1.

What a lead reports

curl "https://api.routeur.app/v1/opportunities?cross_venue=true&limit=1" \
  -H "X-API-Key: $ROUTEUR_API_KEY"

{
  "data": [
    {
      "relation": "equivalent",
      "cross_venue": true,
      "left":  { "venue": "kalshi", "id": "KXMLBTOTAL-26SEP171235MILPIT-9", "title": "Over 8.5 runs scored", "liquidity": "deep", "…": "…" },
      "right": { "venue": "polymarket", "id": "mlb-mil-pit-2026-09-17-total-8pt5", "title": "Milwaukee Brewers vs. Pittsburgh Pirates: O/U 8.5", "…": "…" },
      "legs": [
        { "venue": "kalshi", "market_id": "KXMLBTOTAL-26SEP171235MILPIT-9", "side": "yes", "ask_usd": "0.54" },
        { "venue": "polymarket", "market_id": "mlb-mil-pit-2026-09-17-total-8pt5", "side": "no", "ask_usd": "0.45" }
      ],
      "cost_usd": "0.99",
      "gross_edge_usd": "0.01",
      "estimated_fee_usd": "0.032375",
      "net_edge_usd": "-0.022375",
      "issues": [
        "unverified: top-of-book depth is unknown; asks are discovery observations",
        "estimated: Kalshi standard 0.07 taker fee for one contract; series fee multipliers and rounding across quantities are not applied",
        "estimated: Polymarket taker fee rate * p * (1 - p) for one share, before rounding",
        "unverified: the covering payout assumes the event settles normally; postponement, cancellation and disputes settle differently across venues",
        "unverified: legs settle in USD and USDC; conversion and transfer costs are not priced"
      ],
      "depth": {
        "executable": false,
        "pairs": "0",
        "cost_usd": "0",
        "fees_usd": "0",
        "net_usd": "0",
        "limited_by": "price",
        "observed_at": "2026-09-17T12:10:12.831Z",
        "issues": [
          "estimated: kalshi KXMLBTOTAL-26SEP171235MILPIT-9 yes fee is the series rate × contracts × p × (1 − p), rounded up to the cent per leg",
          "estimated: polymarket mlb-mil-pit-2026-09-17-total-8pt5 no fee is the market's rate × shares × p × (1 − p), before rounding",
          "stale: leg books were read 23s apart"
        ]
      }
    }
  ],
  "graph_run": 74
}

A one-cent gap at the top of the book, eaten by three cents of fees: a typical lead. The fields:

Field	Type	Meaning
`relation`	string	The relation from the left market’s side.
`cross_venue`	boolean	The legs are on different venues.
`left`, `right`	Market	Both markets in full, with liquidity fields.
`legs`	array of 2	Each leg’s `venue`, `market_id`, `side` (`yes` or `no`) and `ask_usd`, the recorded top-of-book ask.
`cost_usd`	decimal	The two asks added, per pair.
`gross_edge_usd`	decimal	$1 minus `cost_usd`.
`estimated_fee_usd`	decimal	Both legs’ taker fees for one contract, from each venue’s schedule.
`net_edge_usd`	decimal	`gross_edge_usd` minus `estimated_fee_usd`. Can be negative.
`issues`	array of strings	Caveats on the top-of-book estimate, each prefixed `unverified:`, `estimated:`, `stale:` or `informational:`.
`depth`	object	The lead sized against live order books. Present for the best leads of each run.

Fees

Venue	Taker fee per contract	Note
Kalshi	0.07 × p × (1 − p), rounded up to the cent	The standard schedule. Series multipliers are not applied in `estimated_fee_usd`; the depth check uses the series’ own rate.
Polymarket, fee model `polymarket_taker`	rate × p × (1 − p)	The market’s own rate, before rounding.
Polymarket, fee model `none`	0
Unknown fee model	0	The issue `unverified: taker fee for … is unknown and counted as zero` is added, so the net edge is an upper bound.

Issues you will see

Issue	When
`unverified: top-of-book depth is unknown; asks are discovery observations`	Always. Top-of-book asks say nothing about size.
`unverified: the covering payout assumes the event settles normally; …`	Cross-venue leads. Postponement, cancellation and disputes settle differently on the two venues.
`unverified: legs settle in USD and USDC; …`	Cross-venue leads. Conversion and transfer are not priced.
`informational: the venues settle a delayed or cancelled release differently; not offered as executable until a release guard exists`	Economics relations. See below.
`stale: legs were observed 2m1s apart`	The two asks were recorded more than a minute apart.

Depth: sizing against live books

After each graph run, the best leads by net edge (150 by default) are checked against the venues’ live order books. Both legs’ ask ladders are walked together: pairs are taken while the next pair’s two asks plus both unit fees still cost less than $1. Kalshi legs are whole contracts with a minimum of one; Polymarket legs use the market’s own minimum order size, in shares. Kalshi fees are rounded up to the cent per leg.

Field	Type	Meaning
`executable`	boolean	At least one whole pair could be bought for less than it pays, after fees and minimum sizes.
`pairs`	decimal	How many pairs could be filled.
`cost_usd`	decimal	Principal across both legs for those pairs.
`fees_usd`	decimal	Taker fees across both legs.
`net_usd`	decimal	`pairs` × $1 minus `cost_usd` minus `fees_usd`.
`limited_by`	string	What stopped the fill from growing. See the table below.
`observed_at`	timestamp	The earlier of the two book reads.
`issues`	array or null	Fee estimates per leg, `stale: leg books were read 23s apart` when reads were more than 10 seconds apart, and any read error.

`limited_by`	Meaning
`price`	The next pair would cost at least its payout. The books were fine; the price was not.
`depth`	A leg’s book ran out of resting size below the payout.
`minimum`	The profitable size is below an order minimum: less than one whole Kalshi contract, or less than Polymarket’s minimum order.
`fees`	Rounded fees consumed the edge.
`unavailable`	A leg’s book could not be read. `issues` says why; nothing is sized.
`informational`	The pair would fill, but the relation rests on a settlement the venues could resolve differently. Never executable.

informational is set on every economics lead. The CPI and Fed relations are proven on the scheduled release, and the venues settle a delayed or cancelled release by different rules. Until a guard confirms the release happened as scheduled, these leads are listed for information only. See Cross-venue pairs.

Only leads with depth.executable could be filled at a profit when the books were read. Everything else is priced from top-of-book asks and may be too thin to fill. On the run above, 36 leads existed and one was executable, for a net of one cent on a thin tennis market that the default floors hide.

Listing leads

GET /v1/opportunities returns the latest run’s leads, executable ones first by depth.net_usd, then the rest by net_edge_usd. Responses are cached for one minute.

Parameter	Type	Default	Meaning
`cross_venue`	boolean	`false`	Only leads whose legs are on different venues.
`executable`	boolean	`false`	Only leads with `depth.executable`.
`limit`	integer, 1 to 200	`50`	Leads to return.
`min_volume_usd`	number	`1000`	Both markets must have traded at least this in the last 24 hours.
`max_spread_usd`	number	`0.05`	Both markets’ round trip (Yes ask plus No ask less $1) must be at most this.
`include_thin`	boolean	`false`	Drop both floors. An explicit `min_volume_usd` or `max_spread_usd` still applies on top.

Both legs have to pass the liquidity floors: a lead is only as good as its thinner side. With the defaults, the run above lists 4 leads; with include_thin=true, 36.

curl "https://api.routeur.app/v1/opportunities?executable=true" \
  -H "X-API-Key: $ROUTEUR_API_KEY"

{ "data": [], "graph_run": 74 }

An empty list is the usual answer, and an honest one. The one executable lead on this run was on a thin market, so it appears only with include_thin=true.

Being told

The leads topic of the live stream pushes every lead of each finished run, in the order above.
The lead.executable webhook fires when a run finds a lead whose books could be filled at a profit of at least your subscription’s minimum. Economics leads never alert.

Relations: what makes a pair provable.
Cross-venue pairs: matched games and releases, and the informational rule.
Liquidity: the grades and the floors.
Order books: the books the depth check walks.
Compare a market across venues: ranking gaps yourself.

Get started

Concepts

Agents & MCP

Webhooks

Reference

The idea

Which legs a relation allows

What a lead reports

Fees

Issues you will see

Depth: sizing against live books

Listing leads

Being told

The idea

Which legs a relation allows

What a lead reports

Fees

Issues you will see

Depth: sizing against live books

Listing leads

Being told

Related