Documentation Index
Fetch the complete documentation index at: https://mintlify.com/mempool/mempool/llms.txt
Use this file to discover all available pages before exploring further.
Overview
The Mempool Visualizer provides real-time insight into Bitcoin’s mempool (memory pool) - the waiting room for unconfirmed transactions. See at a glance how busy the network is, what fee rates are being used, and when your transaction might confirm.What is the Mempool?
The mempool is where transactions wait before being included in a block. When you broadcast a Bitcoin transaction, it enters the mempool of nodes across the network. Miners select transactions from their mempool to include in the next block, typically prioritizing those with higher fee rates.The mempool is not a single global entity - each node maintains its own mempool. Mempool.space aggregates mempool data to provide a representative view of network activity.
Key Features
Real-Time Updates
Live mempool data updates every few seconds, showing you the latest transaction activity and fee rates.
Fee Rate Visualization
Color-coded layers represent different fee rate tiers, making it easy to see fee distribution at a glance.
Interactive Charts
Hover over the graph to see detailed breakdowns of mempool size, transaction count, and fee ranges at any point in time.
Historical View
Toggle between different time windows (2 hours, 8 hours, 24 hours, 1 week) to analyze mempool trends.
Understanding the Visualization
Mempool Graph
The main mempool graph displays transaction data across multiple dimensions:- Y-Axis
- X-Axis
- Colors
Mempool Size (vBytes)The vertical axis shows the total size of the mempool in virtual bytes (vB). This represents how much transaction data is waiting to be confirmed.
- Empty mempool: Near 0 vB
- Normal activity: 10-50 million vB
- High congestion: 100+ million vB
Mempool Blocks
Below the main graph, you’ll see projected “mempool blocks” - virtual blocks showing which transactions would be included in the next several blocks if they were mined right now. Each block shows:- Median fee rate: The middle fee rate in that block
- Fee range: From lowest to highest fee in the block
- Block fullness: Visual indicator of how full the block is
- Total fees: Sum of all transaction fees in the block
Mempool blocks are projections, not guaranteed confirmations. Actual blocks may differ due to new transactions, RBF (Replace-By-Fee), or miner preferences.
How to Use
Checking Network Congestion
-
Look at the height of the mempool graph:
- Low height = network is clear, transactions confirm quickly
- High height = network is congested, higher fees needed
-
Check the number of mempool blocks:
- 1-3 blocks = low congestion
- 4-6 blocks = moderate congestion
- 7+ blocks = high congestion
Choosing Transaction Fees
View Current Fees
The fee estimator on the dashboard shows recommended fees for different confirmation priorities.
Find Your Transaction
If you’ve already sent a transaction, you can search for it to see where it sits in the mempool.
Reading the Data Tooltip
Hover over any point on the graph to see:- Timestamp: Exact time of the data point
- Total Size: Complete mempool size at that moment
- Transaction Count: Number of unconfirmed transactions
- Fee Rate Breakdown: Size distribution across fee tiers
- Cumulative Totals: Running total for each fee tier
Advanced Features
Weight Mode Toggle
Switch between virtual bytes (vB) and weight units (WU) for different perspectives on block space:- vBytes: Standard unit, easier to understand
- Weight Units: Raw block space measurement (1 vB = 4 WU)
Inverted Graph
Flip the graph to display highest fees at the bottom instead of the top - useful for different analytical perspectives.Time Window Selection
2 Hours
Best for real-time monitoring and immediate fee decisions.
8 Hours
Good for understanding recent trends and patterns.
24 Hours
Shows daily cycles and weekend vs. weekday patterns.
1 Week
Reveals longer-term trends and network behavior.
API Endpoints
Access mempool data programmatically:Understanding Mempool Behavior
Why Does the Mempool Clear?
The mempool size fluctuates based on:- Transaction inflow: New transactions being broadcast
- Block mining rate: How quickly miners find blocks
- Fee rates: Whether users are willing to pay current rates
- Time of day: Business hours vs. off-hours activity
Weekend Effect
The mempool often clears on weekends when:- Fewer transactions are broadcast
- Blocks continue to be mined at the same rate
- Lower demand means lower fees
Fee Market Dynamics
When the mempool is full:- Users compete for block space by raising fees
- Lower-fee transactions get pushed back
- Some transactions may be dropped if they’re too old or have too-low fees
- The market reaches equilibrium when demand matches supply
Troubleshooting
Why isn't my transaction showing?
Why isn't my transaction showing?
Your transaction may not appear if:
- It hasn’t been broadcast to the network yet
- It was rejected for having too-low fees
- It’s using a non-standard script
- There’s a temporary sync issue (refresh in a few moments)
Why did my projected confirmation time increase?
Why did my projected confirmation time increase?
Confirmation estimates can change due to:
- New higher-fee transactions entering the mempool
- Slower-than-expected block times
- Other transactions being accelerated
What does 'in template' mean?
What does 'in template' mean?
A transaction “in template” is currently in a mining pool’s block template, meaning it’s likely to be included in the next block they mine.
Best Practices
Check the mempool before sending time-sensitive transactions
Use the recommended fee rates from the dashboard
Monitor mempool trends during high-activity periods
Consider waiting for weekends if your transaction isn’t urgent
Use transaction acceleration for stuck transactions
Related Features
Fee Estimation
Smart fee recommendations based on mempool conditions
Transaction Acceleration
Speed up stuck transactions with CPFP acceleration
Blockchain Explorer
Explore confirmed transactions and blocks
Mining Dashboard
See which pools are mining blocks and their activity