Build a complete engineering specification
Connect architecture, interfaces, requirements, decisions, and implementation details with precise references between specs, diagrams, nodes, and connectors.
Connect · Design · Build
One workspace.Every discipline.
Architect, Design and engineer systems together—from concept to deployment.
Structured thinking. Connected systems. Built forward.
Web clientCustomer experience
API gatewayRoutes authenticated traffic2
Auth serviceValidates identity
Payment serviceOwns transactions1
Event streamPublishes outcomes
HTTPSvalidatecharge
Animated walkthroughStep 2 of 4 · Validate the request
@
Linked specificationEvery node has context
Project-aware agentCreate · edit · validate
578editable symbols
27spec-backed connectors
12visual themes
8professional disciplines
Full-stack engineering collaboration
Give every engineering team the context it needs.
Software, infrastructure, electrical, mechanical, and robotics teams can work in the same organization while keeping the notation and detail their work requires. Diagrams, specifications, decisions, and reviews stay connected as the design evolves.
Collaborate live, review asynchronously
Co-edit the system in real time, preserve version history, and share expiring review links so subject-matter experts can contribute without losing the thread.
Govern access without slowing the work
Organize people into role-based workspaces, restrict sensitive projects, require SSO or MFA, and retain an audit trail of important changes.
ORGANIZATIONPlatform Architecture4 / 12 seatsProjectsPeopleSecurityAudit
LIVE PROJECTPayments platform 3 collaborators
v18
Version savedConflict-safe history
↗
Review linkExpires in 7 days
A connected engineering workflow
Move from the first sketch to a design others can trust.
Turn an early concept into a reviewable engineering record without separating the visual system from the decisions that shaped it.
01
Model in the language of the discipline
Use focused libraries, professional connectors, engineering metadata, smart routing, and quality checks on one unbounded canvas.
02
Specify decisions in context
Create first-class specifications and type @{name} to reference diagrams, nodes, connectors, or other specs with backlinks.
03
Review the whole system
Share a governed review or turn routes into an animated walkthrough that explains complex behavior without redrawing the architecture.
Living engineering specifications
Specifications that stay connected to the work.
Write requirements and decisions beside the engineering work they explain. Reference a diagram, another specification, an exact component, bundle, or connector—then follow the relationship in either direction.
- 01Reference preciselyPoint to the whole system or the one component, bundle, or route a decision actually affects.
- 02Navigate both waysOpen the canvas from a spec, or use a backlink on a diagram item to find every explanation.
- 03Share durable contextExport Markdown, HTML, Word, or an editable project while preserving the engineering narrative.
AURELIA-R1 harness release
Keep power, EtherCAT, and safety routing traceable. The controlled requirements reference @{Harness and cable topology}.
BOM lines, bundle lengths, coverings, and release checks stay tied to the active Harness configuration.
⌁
BUNDLE REFERENCEB-LEG-L · left leg trunk
Focus →Built for technical clarity
The detail engineers need.
A workspace the whole team can use.
Struct agent
A project-aware agent inside the editor.
Ask for a custom diagram or a precise edit. The signed-in agent inspects the current project, changes the canvas directly, updates linked engineering records, and checks the result before reporting completion.
Struct agentWorking in Checkout platform
Project contextAdd fraud scoring to the payment flow and reroute authorization through it.
Diagram updated
I inspected the current flow, added Fraud scoring before authorization, and rerouted the approved and declined paths. I also linked the decision to the payment reliability Specification.
Architecture checks passVisual checks passSpecification linked
Project changesValidated now
- Canvas
- 1 node · 5 routes updated
- Specification
- Payment reliability linked
- Review
- Ready for engineering review
- Create custom software, cloud, data, network, electrical, mechanical, and robotics diagrams directly.
- Edit the inspected project; create Specifications, Review threads, links, workbooks, and governed exports.
- Run functional and visual checks after diagram changes. Access requires an account: 5 free or 50 paid prompts per UTC day.
Private by design
Choose where your architecture lives.
Use governed organization sync for team projects or keep sensitive drafts in private offline mode. Product analytics never receives diagram or specification content.
Purpose-built canvas
UML, cloud, data, agent, and engineering systems.
Browse 56 semantic shapes, 338 AWS and Kubernetes icons, 184 professional engineering symbols, six agentic patterns, and 27 specification-backed connector presets with standards provenance.
Open interchange
Move between tools without starting over.
Import Mermaid, PlantUML, images, or editable projects. Export full-fidelity SVG, PNG, PDF, Struct JSON, Mermaid, Word, Markdown, HTML, or text.
Quality built in
Make clarity repeatable.
Hierarchical, radial, and grid layouts; tidy spacing; architecture checks; named layers; checkpoints; reusable libraries; and 12 nondestructive visual themes.
A library that speaks your discipline
Use the symbol professionals expect.
Move between focused libraries instead of hunting through one endless list. Every item places as an editable, connectable node and can be pinned to the main toolbar.
Shape library578 editable symbols · 27 specification-backed connector presets
⌕Software architecture and UML56 semantic shapes
▣System boundary□Service▥Database♙Actor≋Event stream◇Component
Synchronous callAsync eventUML dependency
AWS and Kubernetes architecture338 provider-native symbols
AWSLambdaAWSAmazon S3AWSAPI GatewayK8sPodK8sServiceK8sIngress
Private ingressData flowCross-zone route
Data, agents, and machine learningPatterns plus 18 ML symbols · labeled core relationships
✦AI agent↻ReAct loop◈Model⌘Vector store≋Feature stream✓Evaluator
Named dataset flowInference requestCore relationship
Network topology and security18 symbols · 4 IEEE/IETF presets
⌁Router⌘Switch⬟Firewall⌬Load balancer◎Subnet↯VPN gateway
IEEE EthernetIPsec tunnelVRRP failover
Software delivery and operations18 symbols · 2 SLSA/OCI presets
⌘Source↻CI build✓Quality gate▣Artifact◇Environment⌁Observability
Build provenanceOCI pushStandards cited
Electrical circuits, controls, and harnesses73 symbols · 12 IEC/IPC presets
〰Resistor▷|Diode⊣⊢Capacitor⏚Ground⊣RelayⓂMotor
IEC conductorHarness wireOff-page net
Mechanical drawing and systems33 symbols · 6 ISO presets
◉MotorCoupling⚙Gearbox⊙Bearing↝Ball screw↔Actuator
ISO liquid flowHidden lineDimension
Robot power, safety, and motion24 symbols · 3 ISO/IEC/ROS presets
◎LiDAR▣Real-time MCU⬡Safety PLC◫Motor driveⓂBLDC motor⊙Encoder
CAN FDEtherCATROS 2 topic
Solutions by engineering discipline
The right tools for each engineering discipline.
Each discipline gets the symbols, connector semantics, starters, metadata, and checks it needs. The organization still has one connected place to review the system.
{ }56 semantic shapes
Software architecture & UML
Model system context, services, data stores, APIs, classes, sequences, states, ER models, and trust boundaries with editable semantic shapes.
- System, layered, service, flow, state, and data starters
- UML relationships, cardinalities, metadata, and diagnostics
☁338 provider symbols
AWS & Kubernetes architecture
Use recognizable provider artwork for deployed technology while keeping every cloud service and Kubernetes resource movable, connectable, and exportable.
- 307 AWS Architecture Icons and 31 Kubernetes symbols
- Terraform and Kubernetes YAML import with icon mapping
✦AI, data & ML
Data, AI & machine learning
Explain RAG, agents, model serving, data pipelines, experiments, evaluation, governance, drift, and human review without flattening them into vague boxes.
- Six editable agentic patterns and specialized AI nodes
- 18 ML engineering symbols and 7 relationship presets
⌁18 symbols · 4 verified presets
Network topology & security
Document devices, subnets, trust boundaries, secure access, traffic management, wireless links, failover paths, and packet observability.
- IEEE Ethernet, IPsec, BGP, and VRRP relationships
- Clear topology, addressing, and security-zone storytelling
↻18 symbols · 2 verified presets
DevOps & software delivery
Map source, CI, quality gates, artifacts, environments, deployment governance, operations, incidents, recovery, and rollback.
- SLSA build provenance and OCI artifact pushes
- Delivery ownership, environments, gates, and operational context
⌁56 symbols · 11 verified presets
Electrical engineering schematics
Create unboxed ANSI/IEC-style circuits, mixed-signal chips, and microcontroller references with terminal-aware conductors and editable engineering metadata.
- IEC conductors, buses, off-page nets, and IPC/WHMA harness data
- References, values, parts, pins, voltage domains, and design checks
⌾33 symbols · 6 verified presets
Mechanical engineering drawings
Build ISO-oriented technical drawings and system schematics with proportioned features, dimensions, datums, GD&T, surface finish, piping, and motion.
- ISO liquid flow, visible, hidden, extension, dimension, and leader lines
- Use dedicated center-mark geometry for axes and circular features
◎24 symbols · 3 verified presets
Robotics architecture & wiring
Separate the functional stack from detailed robot wiring while preserving power, independent safety, deterministic control, perception, feedback, and physical motion.
- ISO CAN FD, IEC EtherCAT, and one-way ROS 2 topic relationships
- Device references, interfaces, supplies, coordinate frames, and explicit safety intent
Feature matrix
One workflow, tailored to each discipline.
Every visual library uses the same local-first canvas, linked specifications, presentation tools, agent handoff, and full-fidelity export pipeline.
| Capability | Software | Cloud | Data & AI | Network | DevOps | Electrical | Mechanical | Robotics |
|---|---|---|---|---|---|---|---|---|
| Focused visual library | 56 semantic shapes | 338 provider symbols | Agentic + ML vocabulary | 18 symbols | 18 symbols | 56 symbols | 33 symbols | 24 symbols |
| Professional relationships | 7 core choices | Core + verified network | Labeled core flows | 4 cited presets | 2 cited presets | 11 cited presets | 6 cited presets | 3 cited presets |
| Starter projects | Context to ER model | Focused cloud canvas | Data pipeline + patterns | Focused network canvas | Focused DevOps canvas | Circuits, chips, MCU | Technical drawing | System stack + wiring |
| Engineering metadata | Owner, technology, status | Provider + resource identity | Model, data, governance | Protocol + boundary | Stage + environment | Ref, value, part, pin | Size, datum, tolerance | Ref, bus, frame, safety |
| Quality checks | Architecture diagnostics | Architecture diagnostics | Architecture diagnostics | Architecture diagnostics | Architecture diagnostics | Electrical design checks | Drafting conventions | Robot completeness checks |
| Linked specifications | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Agent skill + validated patches | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Animated presentation | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| SVG, PNG, PDF, project export | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Visual and versionable
Draw directly on the canvas or work from code.
Start from a template, draw by hand, import Mermaid, or ask an external agent for a first pass. However the diagram begins, the result stays editable.
- 01Fast visual editingDrag, route, group, resize, style, annotate, and arrange.
- 02Text-based interoperabilityRound-trip supported Mermaid families and validate agent patches.
- 03Documentation that points backReferences remain connected to the exact diagram item they explain.
CanvasMermaid
SyncedCheckout flow3 nodes · 2 connections
ENTRY POINTWeb client
HTTPS
EDGE SERVICEAPI gateway
charge
DOMAINPayment service
architecture.mmdValidated
1flowchart TD
2client["Web client"]
3
4gateway["API gateway"]
5
6service["Payment service"]
7
8client -- "HTTPS" --> gateway
9gateway -- "charge" --> servicePrivate local multiplayer
Stay in sync.
Leave the cloud out of it.
Invite a teammate on the same network and collaborate in real time—no account, hosted room, or cloud relay. Diagram changes travel directly between verified peers and remain available when the internet is not.
- ↔The whole architecture stays in contextCanvas state, routed connectors, metadata, specifications, and presentation order move together.
- ⌁Use the connection you already haveWork over local Wi-Fi or a phone hotspot, with Bluetooth Low Energy fallback on macOS.
- ◇Verify before you shareCompare fingerprints, then exchange authenticated AES-256-GCM updates with replay protection.
LANOffline hotspotmacOS Bluetooth
Desktop distribution is temporarily paused. Check back for the next release.
One connected system
Every discipline connects to the same architecture.
Keep software, infrastructure, electronics, mechanics, and robotics aligned around the interfaces and decisions they share. Struct preserves each field’s visual language without splitting the system into separate stories.
Explore Struct resources
Questions, answered
What teams usually want to know.
Start with a private diagram or a shared organization, and choose how much process the work needs.
Can I use Struct for free?+
Yes. Create a hobby organization for synchronized projects or choose private offline mode without an account.
Where are my diagrams stored?+
Signed-in projects synchronize to the selected organization. Private offline projects remain in the current browser profile. Optional analytics measures visits, editor activity, and download clicks, but never receives diagram or specification content, names, files, or review-link secrets.
How does team collaboration work?+
Organizations isolate members, seats, projects, grants, versions, retention, and audit history. Authenticated WebSockets exchange collection-keyed changes by stable node, connector, stroke, and specification ID, while optimistic version checks reject conflicting writes for retry.
Does Struct support SSO and MFA?+
Yes. Enterprise organizations can require OpenID Connect SSO with PKCE, verified email, domain allowlists, and just-in-time provisioning. Password accounts can enable TOTP authenticator codes and receive eight one-time recovery codes.
Which Mermaid diagrams can I import?+
Struct supports Mermaid flowcharts, class diagrams, sequence diagrams, state diagrams, and entity-relationship diagrams, with export back to Mermaid where the format can preserve the model.
Which technical disciplines does Struct support?+
Struct provides focused libraries and workflows for software architecture and UML, AWS and Kubernetes cloud architecture, data and AI, networking, DevOps, electrical engineering, mechanical engineering, and robotics. Each discipline includes relevant starters, symbols, connector semantics, metadata, and shared specification, presentation, agent, and export workflows.
Does Struct include real AWS, Kubernetes, and engineering symbols?+
Yes. Cloud contains 307 AWS Architecture Icons plus the Kubernetes logo and 30 resource symbols. Engineering provides 184 symbols and 27 connector presets tied to named IEEE, IETF, SLSA, OCI, IEC, IPC/WHMA, ISO, EtherCAT, ROS 2, or OMG specifications, including electrical schematic parts, harness/device matings, ISO-oriented mechanical drafting, and robotics communication relationships.
What can the Struct agent do?+
Signed-in users can ask the project-aware agent to create or edit the current diagram, update linked Specifications, prepare engineering deliverables, and run deterministic functional and visual checks. Free accounts receive 5 prompts per UTC day and entitled paid accounts receive 50. For external coding-agent workflows, the downloadable agent kit can still produce validated Struct results without placing model credentials in the editor.
How do specifications link to diagrams and nodes?+
Type an @ reference in a specification to find another specification, a diagram, an exact node, or a connector. Struct renders a preview and adds a backlink to the referenced diagram item, so readers can move from the decision to the visual context and back again.
Can I collaborate without the internet?+
Yes. The web shell is offline-capable after its first successful load. Desktop peers can also sync canvas changes, specifications, metadata, and presentation order directly over encrypted LAN, an offline hotspot, or Bluetooth on macOS—without a cloud relay.
Any discipline