The whole API is one endpoint.

First query

1. 01Sign in at app.outcome.sh. Magic-link email, no password and no credit card.
2. 02Create a key under API Keys in the dashboard. Keys are shown once.
3. 03POST your SQL:

curl -X POST https://api.outcome.sh/v1/execute \
  -H "Authorization: Bearer $OUTCOME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"query": "SELECT max(created_time) AS last_trade FROM trades"}'

API keys

Every request authenticates with an API key in the Authorization header. Keys are created and revoked in the dashboard, belong to your team, and spend the team credit balance. The same key works for the execute endpoint and the MCP server.

Authorization: Bearer $OUTCOME_API_KEY

• +Each key is rate limited to 60 requests per second.
• +A leaked key can spend your credits. Revoke it from the API Keys page.
• +GET /v1/schema is public and needs no key.

Execute a query

Runs a single read-only SQL statement against the warehouse and returns the rows as a JSON array. SELECT, WITH, EXPLAIN, and SHOW are permitted; anything that writes, touches system tables, or reaches external data is rejected before it runs.

Request body

Example

curl -X POST https://api.outcome.sh/v1/execute \
  -H "Authorization: Bearer $OUTCOME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"query": "SELECT ticker, yes_price FROM markets ORDER BY volume_24h DESC LIMIT 5"}'

[
  { "ticker": "KXMENWORLDCUP-26-ES", "yes_price": 0.999 },
  { "ticker": "KXTECHLAYOFFS-26", "yes_price": 0.911 },
  { "ticker": "KXUSAALIENS-27", "yes_price": 0.074 }
]

Usage headers

Every successful response reports what the query cost:

HTTP/2 200
X-Credits-Used: 3
X-Duration-Ms: 118
X-Bytes-Read: 204811520
X-Credits-Remaining: 49997

The live schema

Returns every queryable table with its columns and exact ClickHouse types. Public, no key required. Feed it to a code generator or an agent before it writes SQL.

curl https://api.outcome.sh/v1/schema

{
  "tables": [
    {
      "name": "markets",
      "columns": [
        { "name": "venue", "type": "LowCardinality(String)" },
        { "name": "ticker", "type": "String" },
        { "name": "yes_price", "type": "Float64" },
        ...
      ]
    },
    ...
  ]
}

The tables

Kalshi is live today, more venues are on the way. The venue column tells rows apart, so queries keep working as venues are added.

Outcome is an analytical warehouse, not a trading feed: new markets, trades, and book updates land within five minutes of the venue. Build research and dashboards on it, not HFT.

Types below are simplified. For exact ClickHouse types, use GET /v1/schema.

-- What does the market believe right now?
SELECT title, round(yes_price * 100, 1) AS chance
FROM markets
WHERE status = 'open'
ORDER BY volume_24h DESC
LIMIT 5

-- Replay one market's price path
SELECT created_time, yes_price
FROM trades
WHERE ticker = 'KXMENWORLDCUP-26-ES'
ORDER BY created_time

-- Tightest markets right now
SELECT ticker, yes_bid, yes_ask, spread_yes
FROM orderbooks
WHERE spread_yes IS NOT NULL
ORDER BY spread_yes ASC
LIMIT 10

-- Liquidity over time for one market
SELECT updated_time, yes_liquidity, no_liquidity
FROM historical_orderbooks
WHERE ticker = 'KXMENWORLDCUP-26-ES'
ORDER BY sequence_number

-- Resolution outcomes across all settled markets
SELECT result, count() AS markets
FROM resolved_markets
GROUP BY result

The MCP server

A remote MCP server for Claude, Cursor, and any other MCP client: the agent discovers the schema and queries the market itself. Streamable HTTP (protocol 2025-06-18), authenticated with your API key, with the same read-only rules, rate limits, and billing as the execute endpoint. Nothing to install or host.

Connect a client

claude mcp add --transport http outcome https://api.outcome.sh/v1/mcp \
  --header "Authorization: Bearer YOUR_API_KEY"

Tools

A typical session: list_tables once, a preview or two, then run_query. Billed tools report credits used in their results.

Credits and limits

1,000 credits equal one dollar. Only successful queries are charged: one base credit, plus one credit per 100 MB scanned, plus a time cost that rises steeply past a minute:

Set spend limits and auto reload in Billing.

Errors

Errors return a JSON body with an error message and, where a machine needs to react, a stable code:

{
  "error": "team spend limit exceeded",
  "code": "team_spend_limit_exceeded"
}