What is an Order Book
Order Book — an electronic list of all open buy orders (bids) and sell orders (asks) for cryptocurrency on an exchange. Shows current market supply and demand.
Order Book Structure
ASKS (sell)
┌────────────────────────────┐
│ Price │ Size │ Total │
├───────────┼───────┼───────┤
│ $40,150 │ 0.5 │ 0.5 │
│ $40,120 │ 1.2 │ 1.7 │
│ $40,100 │ 2.0 │ 3.7 │ ← Best ask price
├───────────┴───────┴───────┤
│ SPREAD: $10 │
├───────────┬───────┬───────┤
│ $40,090 │ 1.5 │ 1.5 │ ← Best bid price
│ $40,070 │ 2.3 │ 3.8 │
│ $40,050 │ 0.8 │ 4.6 │
└───────────┴───────┴───────┘
BIDS (buy)
Key Terms
| Term | Description |
|---|---|
| Bid | Buy order |
| Ask | Sell order |
| Spread | Difference between best bid and ask |
| Depth | Market depth (volume at levels) |
| Best Bid | Highest buy price |
| Best Ask | Lowest sell price |
Order Types
Limit Order
Added to book:
├── Buy: below current price
├── Sell: above current price
├── Waits for execution
└── You are Maker
Market Order
Takes from book:
├── Executes instantly
├── At best available prices
├── Can move price
└── You are Taker
Market Depth
Order book visualization:
Asks (sell)
╱ ╲
╱ ╲
╱ ╲
────────── Current price ──────────
╲ ╱
╲ ╱
╲ ╱
Bids (buy)
Wider "mountains" = more liquidity
How to Read Order Book
Narrow Spread
Spread: 0.01-0.05%
├── High liquidity
├── Easy to enter/exit
├── Minimal slippage
└── Sign of healthy market
Wide Spread
Spread: 0.5-2%+
├── Low liquidity
├── Hard to trade
├── High slippage
└── Be careful with volume
Wall
Large order at one level:
├── Buy wall: many buyers → support
├── Sell wall: many sellers → resistance
├── Can be real or spoofing
└── Watch for changes
Order Book vs AMM
| Criteria | Order Book | AMM (DEX) |
|---|---|---|
| Mechanics | Order matching | Curve algorithm |
| Liquidity | From traders | From LP providers |
| Slippage | Depends on depth | Depends on pool size |
| Examples | Binance, Kraken | Uniswap, Curve |
Price Impact
Large Market Order
Buying 10 BTC market order:
Book before:
Ask $40,100: 2 BTC → filled
Ask $40,120: 3 BTC → filled
Ask $40,150: 5 BTC → partially filled
Average price: ~$40,125
Slippage: 0.06%
Thin Book
With low liquidity:
├── Even small order
├── Moves price significantly
└── Slippage can be 1-5%
Order Book and DCA
For DCA strategy, understanding order book is useful:
How to Use
When buying:
1. Look at spread
├── Narrow → market order OK
└── Wide → use limit order
2. Evaluate liquidity
├── Deep book → buy immediately
└── Thin book → split into parts
3. Limit orders save money
└── Maker fee < Taker fee
For Automatic DCA
On exchanges with auto-buy:
├── Usually uses market order
├── For small amounts OK
└── For large — better manual limit
Order Book Strategies
1. Limit Below Market
Current price: $40,100
Place bid: $40,000
├── Save ~0.25%
├── May not fill
└── For patient buyers
2. Wall Analysis
Large sell wall at $45,000:
├── Price may not break through immediately
├── Can sell slightly below
└── Or wait for breakout
3. Following Volume
If large bids appear:
├── Possibly big player buying
├── Potential growth
└── No guarantee
Analysis Tools
| Tool | Function |
|---|---|
| TradingView | Charts + depth |
| Coinalyze | Real-time order book |
| Exchange interface | Native book |
| Exchange APIs | For algorithms |
Common Mistakes
- Ignoring spread — important for entry points
- Trusting walls — can be spoofing
- Large market orders — use limit instead
- Not accounting for slippage — especially on small coins
Important: For DCA investors, order book isn't critical, but understanding it helps save on fees and get better prices. Use limit orders slightly below market — it's a simple way to optimize purchases.
