How to use Schematica

Start here

An empty board asks What are you drawing? and offers a start for each kind of work. The choice only changes what comes first; every part and feature stays available.

Hardware

Choose Guided walkthrough (hardware, UART) to find and repair an interface mismatch, then hand over a review package or a technical report.

Network

Choose Network, then open Examples → Three-Tier Web App (DMZ) or Cloud VPC, or search the palette for routers, switches, firewalls and servers. Interface declarations are optional on a network board.

Security

Choose Explain a CVE (no API key) or Rebuild an incident from a log (no API key). Present → Replay incident plays a rebuilt log on its own clock.

Your first board

Build a simple controller-and-sensor sketch in a few steps.

1. Name your board

   Open the editor and enter a title in the top-left field. If a board is already open, choose New project: the current board stays in its own project, reachable from the Projects button beside the title.

2. Add two parts

   Search the left palette for MCU and add it to the canvas. Search for Temp sensor and place it beside the controller. Click or drag a palette item to add it.

3. Connect their ports

   Hover over a card to reveal its ports. Drag from the MCU's I2C port to the sensor's I2C port. The wire follows the parts when you move them.

4. Add the details

   Select a card or wire to edit it in Properties. Set labels, part numbers, rails and connection information that you know. Add the power and ground connections your design needs.

5. Review and save

   Press F to fit the diagram. Use Check to inspect findings, then Save to download an editable .schematica.json file. Export prepares an image or a handoff.

Find your way around

Hover over a toolbar icon to see its name and shortcut. In a narrow window the labelled buttons, such as Examples and Review, show only their icons.

On a phone, Schematica opens boards to view and present: open an example, a file or a share link, pan with one finger and pinch to zoom, tap a part for its details, play the story or the incident replay, and read the review results. Drawing and editing need a tablet or a computer.

Top toolbar

Name the board, choose drawing tools, zoom, open examples, run checks, save and export.

Left palette

Choose Hardware, Network or Security to put that kind of part first, search every part from embedded hardware to network, security, people and process-flow symbols, and create custom parts under My parts.

Canvas

Arrange cards and connections. Scroll to zoom; hold Space and drag to pan. F fits the whole drawing.

Properties

Select something on the canvas to edit its details. Select several items to reveal alignment and spacing controls.

Review

The Review button beside BOM opens interface readiness, the review package, the technical report, interfaces, revisions and saved views.

Press B to show or hide the parts palette, and P to show or hide the right panels. Click outside a text field before using editor shortcuts.

The Assistant is a movable panel. Drag its title bar anywhere on the page, or focus the title bar and use the arrow keys (Shift for larger moves). It remembers its position on this device; resizing or collapsing keeps a drag grip reachable.

Toolbar icon reference

Match each symbol to the top toolbar. Highlighted buttons mark the active tool or enabled display option; disabled buttons need an applicable selection or history. The board-title field names the current document.

Palette icon reference

Click a part to place it near the center of the view, or drag it to a location on the canvas. These are architecture symbols with default ports, not verified component specifications. Choose the real model and review its interface declarations before relying on a connection.

The categories run from embedded hardware (Compute through Automotive) to the parts of an IT estate: Endpoints, System & Cloud, Operating Systems, Network, Security & Edge, Facilities, People, Process Flow shapes and Threats. Hover over a tile to read what the part is for. Fold the categories you do not use; the Recent row keeps the parts you placed last. Search understands common aliases, so wifi, ap or firewall finds the right tile.

Every built-in part

Expand a category to see every icon, its purpose and its default ports. Search by name, category or port to narrow the list. Custom parts can use different icons and ports.

Panels and status icons

These controls appear in the floating panels, on selected items or inside dialogs. Read the label beside a symbol to distinguish actions that use the same shape.

Draw and connect

Parts and labels

Use the Select tool (V) to move cards. Double-click text to rename it, or edit the selected item in Properties. Use My parts → + New to define a reusable part with its own ports and fields.

Wires and buses

Drag between ports to connect them, or choose Draw wire (C). To connect with the keyboard, select a card and choose Connect… (or press Shift+C), choose both parts and ports, then Create connection.

Select a wire to change its bus, label, arrowheads, line style or traffic flow. Drag a selected endpoint handle to another port to reconnect it. Unlock a part if it is missing from the Connect ports form.

Bus legend, beside Explore, lists the chips shown on wire labels (PWR, GND, I2C, UART and so on) with their bus names, and Signal-flow animation moves dashes along wires whose traffic flow is set; it illustrates declared flow and is not a simulation.

Zones, swimlanes and notes

Use Z to draw a zone around related parts, L to draw a swimlane, and N to add a note. Zones group an area; swimlanes organize stages or layers, and dragging the divider between two lanes resizes them; notes explain assumptions and decisions.

Tidy the layout

Shift-click to select several items, then use Align, Distribute or Tidy spacing in Properties. Leave enough room between cards for ports and labels. Connections route around nearby cards and notes automatically.

The More menu at the right end of the toolbar holds two drawing aids that are on by default: Grid dots shows the background dot grid, and Snap to grid snaps positions while you arrange items and pulls a card onto the nearest lane centreline when you drop it inside a swimlane. Turn snapping off when you need free positioning.

Press K to lock or unlock selected items. Locked items keep their positions during dragging, alignment and deletion. Their other properties remain editable.

Open Check → Layout quality to find overlaps, obscured labels and wires crossing unrelated cards. Move the affected cards or adjust their spacing, then check again.

For a large board, open Explore (/) to search placed parts, filter by bus and change the reading detail. Reset exploration restores the view. These filters do not remove parts from the board.

Review the design

Check examines the information you have declared, including bus mismatches, address conflicts, missing connections and power estimates. Select a finding to locate the affected items.

Open Review → Interfaces to record a connection's limits and both endpoints' capabilities. Enter known direction, voltage, protocol, bandwidth and source references. Leave unknown values blank, and save the interface before moving on.

Review → Readiness says whether the board is ready for an interface review: every applicable connection checked and no design-rule errors or warnings. Check → Design rules links to it from the coverage line.

On a network or security board, interface declarations are optional, and Readiness says so instead of reporting a failed review. A board with no applicable connection reads Interface review not applicable.

Checked

The supplied declarations pass the applicable comparisons.

Failed

The supplied declarations conflict. Inspect the finding and resolve it.

Unassessed

Information needed for assessment is missing.

Not applicable

The connection is excluded from interface assessment, such as a flow link.

Use Review → Advanced → Requirements to allocate requirements and record verification methods and evidence. Save a named revision before a major change so you have a useful comparison baseline.

Save, recover and export

The working board is autosaved in this browser for this website. Use Save for a portable backup. Each website address and localhost have separate browser storage.

The Projects button beside the title lists the projects kept in this browser. Each has its own board, autosave and revisions; New project starts an empty board, choosing a project reloads the editor on it, and the menu shows when each was last saved to a file.

Review → Revisions saves and restores named snapshots on this device; named revisions do not rotate out like automatic ones. Loading an example, opening a file or importing a KiCad netlist keeps the previous board as a revision, and the notice that follows offers Restore previous board. Export important revisions to keep them outside browser storage.

A share link contains the board's content. Give it only to people who should see that content. For a team discussion, use Team reviews in the palette; it appears when your server has that service enabled.

Present and record

Open Present → Edit story steps, frame an area and choose + Add step from current view. Select parts and use Link selection to keep the step linked to them. Add captions and reorder the steps.

Choose Present → Present story to play the story, a guided tour through its steps. Arrow keys navigate, Space plays or pauses, and Escape exits. Interactive HTML exports keep the story available offline. Replay incident, on a board rebuilt from a log, is different: it plays the log on its own clock.

Use Present → Record video to record the canvas as video or GIF; while it records, the Present button shows the running time and its menu starts with Stop recording. Present → Export… opens the Export dialog, where Loop GIF saves a short, seamless animation of the current board.

Use the assistant

Press A to open the assistant. Configure a provider, model, Base URL and API key, then Save and Test connection. Drawing, checks and exports work without the assistant.

Ask for a concrete change, review its preview and findings, then Apply changes or Discard draft. Applied changes can be undone. Keep Preview changes before applying enabled while learning.

Review this controller-and-sensor board. Identify missing interface declarations and explain what evidence I need. Leave unknown values blank.

You can attach text, PDF or DOCX sources. Selected extracted text is sent to your configured provider when you send a message. Remember the key on this device only when you want browser persistence. Provider use may be billed by that provider.

Explain an attack or incident

Ask the assistant to draw how an attack works. It builds the picture from threat parts, trust-boundary zones and labelled wires, then adds a step-by-step story.

1. Describe the attack

   Open Assistant (A) and describe the vulnerability or attack, or paste a link to an advisory. The assistant reads only the links you give it. Give it a CVE id and it draws the published record, using the CVE database configured on the server when there is one and otherwise CVE.org and NVD, and tells you the source.

2. Rebuild an incident from a log

   Attach a JSON log of timestamped actions (ts, actor, action, and optionally target and phase) and ask the assistant to show what happened. Each phase becomes a story step, with one stop per action in time order.

3. Review, edit and present

   Review the preview, then choose Apply changes. Edit the result like any other board, and choose Present → Present story to walk through the steps.

Draw how CVE-2021-44228 lets an attacker reach our logging server, then make a short story of the steps.

Replay an incident and mark conditions

A board rebuilt from a log shows Replay incident at the top left of the canvas and under Present. The replay plays the log on a clock: parts light up as the attacker reaches them, and each part takes on the condition its step leaves it in, such as suspicious, exploited, infected or exfiltrating, as a tag and a halo. Leaving the replay restores the board's own marks.

To record what happened to a part on any board, select it and choose a Condition in Properties. Examples → Enterprise Network: Phishing to Ransomware shows an office network drawn with the Endpoints, Network, Security & Edge, Facilities and People parts, with each host marked by its condition.

Examples → Security holds ready-made boards to start from: CVE explainers, incident replays rebuilt from fictional logs, and clean network topologies.

Build from a CVE, a write-up or a log

Build from a source, under Options and sources in the Assistant panel, builds these boards with no assistant provider configured; the empty board's start card offers the CVE and incident-log builds too. Nothing is sent to a model. Each button asks before replacing a board that has work on it, and one Undo brings the previous board back.

1. CVE id

   Choose CVE id, type an id such as CVE-2021-44228 and press Build. The record is fetched from CVE.org, with NVD for a missing score; only the id leaves the browser. The board shows the attacker in a zone named by the attack vector, a person when user interaction is required, the affected products with their version ranges, the flaw with its CWE and CVSS, and the impact on confidentiality, integrity and availability. A note holds the fix, the source, the references and any assumptions. Choose Present to step through Who acts, Boundary crossed, The flaw, Impact and Fix.

2. Write-up

   Choose Write-up, then paste the text or choose a file: an advisory, a blog post, a Markdown note or a script. The document is read for the CVE it names, whose record is fetched, and for the steps it describes: numbered or bulleted lines, lines after a shell prompt, request lines and commands inside code fences. The steps become quoted stops in a Steps from the write-up story step on a proof-of-concept card. Nothing is run, resolved or tested. A document that names no CVE still draws, and every missing fact is listed as an assumption.

3. Incident log

   Choose Incident log. The dialog shows the log format and a Download a sample log link; choose Choose log file… and pick a JSON file of timestamped actions, the same shape the assistant accepts: an object with actions, or a bare array, where each action has ts, actor and action. The board is rebuilt in the browser with its timeline, and Replay incident appears at the top left of the canvas.

Appearance and language

Click the appearance icon to cycle Light → Dark → System. A sun, moon or monitor shows the current mode. System follows your operating system, and your choice is remembered on this device.

The 中文 / EN button switches the interface and this guide between English and Simplified Chinese. It does not translate text you wrote on your own board.

Export theme lets you choose a separate appearance for downloads. Automatic SVG follows the reader's system appearance; other automatic exports use your current appearance.

Keyboard shortcuts

Click outside text fields to use these shortcuts. The ? button in the editor opens the same reference. Ctrl is shown on Windows and Linux; ⌘ is shown on macOS.

Common questions

More guides

This page is the complete guide to the website. The application's source distribution also includes a first-review tutorial, a full user guide covering imports, comparisons and team reviews, an editor reference with detailed limits, and a troubleshooting guide, all in its docs folder.