• Devices
  • Cables
  • Groups
  • Diagnostics
  • Providers
  • Your networks
  • ipaddr.js
  • qrcode-generator

A whole network. Replaces the canvas.

Examples

My templates

A saved selection. It goes in beside what you have, moved to the next free subnet.

My blocks

Select a node or link to configure.

Selected

Shift-click adds or removes one. Esc clears the selection.

Tap devices to add or remove them.

Change all of them

A field that says "mixed" differs between them. A field left blank, or as it is, is not changed.

{n} counts up, {n:02} pads it to two digits, {name} is the current name. With Find filled, only that text in each name is replaced.

No subnet is declared yet. Declare one on the Subnets tab first.

Each one takes the next free address there, and its gateway and DNS come from the subnet.

There is no switch or access point on the map to move them to.

Each one's cable moves to the next free port there. The device keeps its address: Move gives it one on another subnet.

There are no groups yet. Add one on the Groups tab first.

Moved anywhere but a rack, a device leaves its units in the rack behind.

None of them is a VM or a container: only those run on another device.

A VM or a container is where the device it runs on is, in its group and its rack.

Only the devices on Wi-Fi change. Auto lets Topo work it out from the access point.

Passthrough bypasses the host OS, connecting the VM directly to the physical switch logic.

Pick the interface this link uses on each end. Occupied ports are marked — you can still pick one, and the node will flag the conflict.

Unassigned switches act as L2 Backplanes.

⚙️ Open in Netplan ↗

Asset

Model and firmware are in one field.

Retired: dimmed on the map, and off the network for the checks and the trace.

    Locate

    History
    Trace off
    Select a node to see its diagnostics.

    Node diagnostics

    Idle

    Where devices sit: buildings, floors, rooms and racks.

    The networks the access points broadcast. No passphrase is kept: a network travels in files and links.

    Who is responsible for what, and how to reach them.

    To check on the next visit

      No findings: every check passes on the map as drawn.

        Accepted

        Known and kept on purpose. They no longer count, and the report lists them with their reason.

          Topo documents a network: its devices, cables, addressing, racks and who is responsible for what, and prints it as a report.

          Runs in your browser. Nothing you add here is uploaded.

          Read-only This network was made by a newer version of Topo. You can look at it, report on it and export it as it is, but changes are not kept.
          Not saved This browser's storage is full or blocked. Back up now so nothing is lost.

            Click a row to select its devices, then use Change all of them to edit them together.

            Click a row to find it on the map. Enter or a double click edits a cell, Esc cancels. Ctrl+V pastes a list down a column.

            Tap a cell to select its row. Tap the same cell again to edit it.

            Nothing here yet.

            Cables

            Drag over empty units, or tap one, to place a device there. Drag a device to move it, and the top edge of the selected one to resize it. Drag from a free port to another device's free port to cable them. Drag a device from the lists onto the units to bring it in, or off the units to take it out. Point at or tap a port to read its cable.

            What are you documenting?

            Pick the view that fits — you can switch anytime, nothing is lost.

            Nobody ever wrote this network down.
            Draw it once, and it checks itself.

            Every device, every subnet, every cable — with the address conflicts, loops and dead gateways found for you, and a report you can hand over. It runs in this tab — no server, no upload, no account — which is why it still works in a comms room with no signal.

            Start a new network

            A blank canvas that saves itself in this browser from the first device.
            Or drop a .json build file, or a whole binder, here.

            First time here? Start from something that already exists.
            Networks you save are kept in this browser, and show up here.

            Shared with you

            Your networks

            Templates

            Saved networks live in this browser only — this is not an account, and clearing site data removes them. Back up for a copy that survives.

            Settings

            Map

            Reports

            History

            Add devices

            More options

            {n} counts up, {n:02} pads it to two digits, {type} is the kind of device. Numbering carries on after the names already on the map.

            Site report

            The findings, the inventory and the diagram as one printable document. Everything here is optional — it only fills in the header.

            What goes in
            Sheets to print
            Tap a square here or on the preview's overview to leave its sheet out.
            Sections Untick a section to leave it out of the technical details. The summary does not change.
            Saved searches Each one prints as a table of the devices it finds. Ticking here changes this report only.

            Share this network

            This link is locked

            Whoever sent it should have given you a passphrase separately. Nothing is sent anywhere — it is checked in this browser.

              Columns

              Which columns the Devices table shows, and in what order. It is saved with the network, and your columns that show here are printed in the report. Spreadsheets keep their own order, so a sheet always reads back.

                Add a column

                Save search

                A type name in another language matches only in that language. Its key (type:camera) matches in every language.

                Columns

                  Expected life by type

                  How many years each kind of device lasts in this network before it shows as past its expected life. Blank uses Topo's usual, shown greyed. A device's own Expected life still wins. Saved with the network.

                    Paste a column

                    One value per line, in the order the rows are shown. A blank line leaves its row as it is.

                    Change

                      Spreadsheet

                      Each sheet is a CSV file any spreadsheet opens (UTF-8, accents and all). Copy as TSV puts the same rows on the clipboard, to paste straight into an open sheet.

                      Paste rows copied from a spreadsheet, or open a CSV file. Rows are matched to devices by id, MAC, IP or name; a row that matches none adds a device. Nothing changes until you apply it.

                      Or paste an ARP table or a DHCP lease list as a router, a switch, a server or a PC prints it, from any vendor: each address seen with its MAC becomes a row.

                      Read as