4 min readbeginner
What is an edge server?
Edge servers are the workhorses of the modern internet: the machines that make websites feel instant by answering requests from just down the road instead of across an ocean.
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Edge server definition#
An edge server is a server located near end users, at the “edge” of a network, that handles requests locally instead of passing them back to a central data centre. Edge servers cache content, terminate connections, and increasingly run application code, so that most requests are answered within a few milliseconds of the user rather than travelling to a distant origin.
Together, many edge servers form an edge network. Each individual server is ordinary hardware; the value comes from where the servers are, and from the routing intelligence that sends every user to the nearest one.
How edge servers work in a CDN#
In a content delivery network, edge servers act as caches. The first time a user near a given location requests a file, the edge server fetches it from the origin, serves it, and keeps a copy. Every subsequent request for that file from the same area is served straight from the cache, with no round trip to origin at all.
This does two things at once. Users get content from a server that might be ten milliseconds away instead of two hundred. And the origin server sees only a trickle of traffic (cache misses and updates) instead of every request from every user. During a traffic spike, the edge absorbs the load.
Modern edge servers do more than cache: they terminate TLS connections close to the user (which speeds up connection setup), optimise images, filter malicious traffic, and answer DNS queries. The step beyond that, running your own code on edge servers, is covered in CDN vs edge computing.
Edge server vs origin server#
| Origin server | Edge server |
|---|---|
| Single source of truth for your application | Many copies distributed near users |
| Usually one location (or a few regions) | Hundreds or thousands of locations |
| Handles every request if unprotected | Absorbs most requests before they reach origin |
| Distance to users determines latency | Positioned specifically to minimise latency |
| Failure means downtime | Failure means traffic shifts to a neighbour |
The two work together: the origin remains the authoritative source of your application and data, while edge servers handle the volume. Most requests should never reach origin.
Where edge servers are located#
Traditional CDN operators place edge servers in internet exchange points and carrier data centres in major cities, wherever many networks meet. The economics of leasing space limit how many locations one company can cover, so most centralised CDNs operate somewhere between a few dozen and a few hundred points of presence, and increasingly in smaller edge data centres nearer to users.
Edge takes this further. Because our network is built from nodes contributed by independent operators, edge servers exist wherever operators run them: 988 edge locations today, spread across cities, towns, and regions that centralised providers don’t reach. The network routes each request to the nearest node with capacity.
What running an edge server involves#
On Edge, anyone can run an edge server. Operators stake tokens, contribute capacity, and earn rewards for the traffic they serve. The network has three node types:
- Host: Provides processing and storage capacity. Designed for mixed devices, and can run behind a home router with no special configuration.
- Gateway: The entry point to the network. Gateways aggregate Host capacity and route each job to the Hosts best placed to complete it quickly.
- Stargate: The masternodes of the network. Stargates run the XE blockchain, provide DNS for network resources, and oversee secure operation.
A Host can run on modest hardware. The minimum specification starts at a quad-core CPU, 1 GB of RAM, and 50 GB of disk. See the network nodes wiki and the Host setup guide for details, or read about the network.
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