A free network diagram maker that keeps your topology private
- Free
- No sign-up
- Works offline
Lay out the zones, the devices and the links between them, then press Present and trace a packet through the network hop by hop.
Present reveals your network diagram one step at a time, on its own.
A network diagram is documentation you need most on the day you can least afford to go looking for it. Free to draw here, no sign-up — and, unusually for this kind of tool, it never leaves your browser.
That last point is the reason to care. A network diagram is a map of your attack surface: subnets, trust boundaries, what sits in the DMZ. Drawing it in a tool that uploads to somebody's cloud by default is a decision most teams make without noticing.
Zones, devices and the boundaries that matter
A useful network diagram is organised by trust boundary first and device second. Group by zone — public internet, DMZ, application subnet, data subnet, management network — and the diagram starts answering security questions as well as connectivity ones.
Label the links, not just the boxes. A line between a load balancer and an application tier is nearly useless; the same line marked 443/TCP, TLS terminated tells a reader what is actually crossing it.
And draw the boundary crossings deliberately. Every arrow that leaves a zone is a place where a firewall rule exists or should — which is exactly the list you want when someone asks what is exposed.
Logical or physical — pick one per diagram
A physical diagram shows what is racked and cabled. A logical diagram shows how traffic flows regardless of hardware. Mixing them produces a picture that is wrong in both readings — a virtualised environment where the boxes are hosts and the arrows are application calls explains nothing.
For cloud environments the logical view is almost always the useful one: VPCs, subnets, security groups and managed services, with the physical layer treated as somebody else's concern.
Present it hop by hop
Press Present and the diagram reveals in the order a request travels — edge, load balancer, application, data — narrated at each hop. That turns the same file into onboarding material, and into the explanation you give during an incident when nobody has time to read a wall of boxes.
How to make a network diagram, start to export
Open the editor, block out the zones first, then place devices inside them. Draw the links and label each with its protocol and port. Export a PNG or SVG for the runbook, or a PDF for the audit pack.
Free, private, and offline
Diagramium is free and there is no paid tier. Draw, present and export PNG or SVG without an account; a free account unlocks the animated export formats — GIF, video and animated SVG.
Your diagram is stored in your own browser, not on a server. It keeps working with the network off, and nothing is uploaded unless you choose to publish it.
Frequently asked questions
Is this network diagram maker free?
Diagramium is free and there is no paid tier. Draw, present and export PNG or SVG without an account; a free account unlocks the animated export formats — GIF, video and animated SVG.
Does my network diagram get uploaded anywhere?
No. It is stored in your own browser and the editor works with the network off. Nothing is uploaded unless you deliberately publish it — which for infrastructure documentation is the property that matters most.
Can I draw a cloud architecture diagram — AWS, Azure or GCP?
Yes. Group by VPC or virtual network and subnet, then place the services inside. The logical view — what talks to what, across which boundary — is usually more useful than mirroring a provider's console.
Should I show IP addresses on the diagram?
Show subnet ranges rather than individual addresses. Ranges stay true far longer, and a diagram that has to be updated whenever a host is replaced stops being updated at all.
What is the difference between a network diagram and an architecture diagram?
A network diagram shows connectivity and trust boundaries — subnets, firewalls, protocols. An architecture diagram shows the software: services, queues and stores, and the calls between them.
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