Overview
Trampoline routing is a technique for the Lightning Network that allows lightweight clients (such as mobile wallets) to send payments without maintaining a full view of the network graph. Instead of computing the entire route from sender to receiver, the sender constructs a route through one or more "trampoline" nodes, each of which independently finds the next hop toward the destination.
How It Works
In standard Lightning routing, the sender must know the complete network topology to find a viable path. Trampoline routing splits this responsibility:
Standard Routing (sender computes full path):
Sender --> A --> B --> C --> D --> Receiver
[Sender knows entire A->B->C->D path]
Trampoline Routing (delegated pathfinding):
Sender --> T1 ~~~> T2 ~~~> Receiver
| |
[T1 finds [T2 finds
path to T2] path to Receiver]
~~~> = trampoline node finds intermediate hops
The sender only needs to know a few well-connected trampoline nodes, not the entire network graph. Each trampoline node uses its own knowledge of the graph to route the payment to the next trampoline or to the final recipient.
Benefits for Mobile Wallets
Mobile and lightweight Lightning nodes face significant constraints:
- Storage: The full Lightning network graph can be tens of megabytes and constantly changing.
- Bandwidth: Syncing gossip data about channel updates consumes significant bandwidth on mobile connections.
- Computation: Pathfinding through thousands of channels is computationally expensive on mobile hardware.
Trampoline routing addresses all three issues by offloading graph storage and pathfinding to well-resourced trampoline nodes.
Privacy Considerations
Trampoline routing involves some privacy trade-offs. The trampoline node knows it is acting as a routing intermediary and can see the next trampoline in the route. However, the use of multiple trampoline hops and onion encryption means no single trampoline node learns the complete route from sender to receiver.
Common Misconceptions
Trampoline routing is not custodial — the trampoline nodes never have control over the funds. The payment is still secured by HTLCs at every hop, maintaining the same trustless guarantees as standard Lightning routing. The trampoline node only assists with pathfinding, not with holding funds.