> ## Documentation Index
> Fetch the complete documentation index at: https://docs.limitless.exchange/llms.txt
> Use this file to discover all available pages before exploring further.
# Get Orderbook
> Retrieve the current orderbook for a market showing all open buy and sell orders
For real-time orderbook updates, use the [WebSocket API](/developers/websocket-events) instead of polling this endpoint. Subscribe to `subscribe_market_prices` with `marketSlugs`.
## Complementary token prices (deriving the NO book)
This endpoint returns a **single, YES-side book**. The `tokenId` in the response is the market's YES position ID, and `bids`/`asks` are quoted in YES-token terms. The two outcome tokens are complementary — a YES share and a NO share always redeem together for exactly \$1 — so their prices satisfy:
```
price(YES) + price(NO) = 1
```
The book you get back already merges **all** liquidity for the market: native NO orders are converted into their YES-side equivalent before aggregation, using the same identity:
```
NO bid @ P ≡ YES ask @ (1 - P) (someone bidding for NO is offering YES)
NO ask @ P ≡ YES bid @ (1 - P) (someone offering NO is bidding for YES)
```
So you never lose NO liquidity by reading the YES book — it's all there, expressed in YES prices.
### Deriving the NO orderbook
To quote or trade the **NO** token, mirror the returned YES book: flip bids ↔ asks and replace every price `p` with `1 - p` (sizes are unchanged).
| NO book | Derived from | Best level |
| ------------------------------- | ------------ | ------------------------------ |
| **NO bids** (orders to buy NO) | YES **asks** | best NO bid = `1 - bestYesAsk` |
| **NO asks** (orders to sell NO) | YES **bids** | best NO ask = `1 - bestYesBid` |
The midpoint and spread carry over directly: `noMidpoint = 1 - yesMidpoint`, and the spread is identical.
```typescript TypeScript theme={null}
type Level = { price: number; size: number };
type Book = { bids: Level[]; asks: Level[] };
// Mirror the YES-side book into the NO-side book.
function deriveNoBook(yes: Book): Book {
const invert = (l: Level): Level => ({ price: 1 - l.price, size: l.size });
return {
bids: yes.asks.map(invert).sort((a, b) => b.price - a.price), // best (highest) first
asks: yes.bids.map(invert).sort((a, b) => a.price - b.price), // best (lowest) first
};
}
// To SELL NO, hit the best NO bid: 1 - bestYesAsk
// To BUY NO, lift the best NO ask: 1 - bestYesBid
```
```python Python theme={null}
def derive_no_book(yes: dict) -> dict:
"""Mirror the YES-side book into the NO-side book."""
invert = lambda l: {"price": 1 - l["price"], "size": l["size"]}
return {
"bids": sorted((invert(a) for a in yes["asks"]), key=lambda l: -l["price"]), # best first
"asks": sorted((invert(b) for b in yes["bids"]), key=lambda l: l["price"]), # best first
}
# To SELL NO, hit the best NO bid: 1 - best_yes_ask
# To BUY NO, lift the best NO ask: 1 - best_yes_bid
```
When you then place a NO order, sign it against the NO `tokenId` (`noPositionId` from [Get Market](/api-reference/markets/get-market)) at the derived price — the price inversion only affects how you *read* the book, not how the order is signed.
## Multi-outcome (NegRisk) markets
In a [NegRisk](/user-guide/negrisk-overview) multi-outcome market, **each outcome is its own market** with its own slug, its own YES/NO tokens, and its own orderbook. Fetch each outcome's book by its slug and derive that outcome's NO book with the same inversion above — there is no single cross-outcome book to invert.
What links the outcomes is a soft pricing constraint, not a shared book: across the *N* outcomes, the YES prices tend toward summing to 1 (exactly one outcome resolves YES), and all the NO contracts are linked for [share conversion](/user-guide/converting-shares). To assemble a full picture of a multi-outcome market, request the orderbook for each outcome slug and mirror each one independently.
## OpenAPI
````yaml GET /markets/{slug}/orderbook
openapi: 3.0.0
info:
title: Limitless Exchange API
description: >-
Production-ready REST API for prediction market trading, portfolio
management, and market data on Limitless Exchange (Base L2).
version: '1.0'
contact:
name: API Support
url: https://limitless.exchange
email: help@limitless.network
servers:
- url: https://api.limitless.exchange
description: Production API
security: []
tags:
- name: Authentication
description: User authentication and session management
- name: Markets
description: Browse, search, and analyze prediction markets
- name: Market Navigation
description: Navigation tree, market pages, and property filters
- name: Trading
description: Create, manage, and cancel orders
- name: Portfolio
description: Position tracking, trade history, and performance
- name: API Tokens
description: Scoped API token management for partner integrations
- name: Partner Accounts
description: Sub-account creation and allowance recovery for partner integrations
- name: System
description: Public API state and availability information
paths:
/markets/{slug}/orderbook:
get:
tags:
- Trading
summary: Get Orderbook
description: >-
Retrieve the current orderbook for a market showing all open buy and
sell orders
operationId: MarketOrderbookController_getOrderbook
parameters:
- name: slug
required: true
in: path
description: Market slug identifier
schema:
example: presidential-election-2024
responses:
'200':
description: Current orderbook with bids and asks
content:
application/json:
schema:
type: object
properties:
adjustedMidpoint:
type: number
example: 0.75
asks:
type: array
items:
type: object
properties:
price:
type: number
example: 0.76
size:
type: number
example: 100
bids:
type: array
items:
type: object
properties:
price:
type: number
example: 0.74
size:
type: number
example: 150
lastTradePrice:
type: number
example: 0.75
maxSpread:
type: number
example: 0.05
minSize:
example: 1
type: number
tokenId:
type: string
example: >-
19633204485790857949828516737993423758628930235371629943999544859324645414627
'400':
description: Market does not support orderbook (AMM market)
'404':
description: Market not found
````