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How to Draw an Integration Architecture Diagram
A practical walkthrough for mapping how your systems actually talk to each other — with real vendor icons instead of generic boxes.
An integration architecture diagram answers one question for whoever's reading it: when data moves through this environment, what actually talks to what? Get that right and a new engineer, an auditor, or a vendor's solutions consultant can understand your landscape in thirty seconds. Get it wrong — vague boxes, unlabelled arrows, no sense of direction — and the diagram creates more questions than it answers.
This is a practical walkthrough, not a theory piece. Every step below uses FlowDiagrams, a free browser-based tool built specifically for this kind of diagram, but the underlying approach applies whatever you draw with.
What belongs in an integration architecture diagram
Before opening any tool, decide what you're actually mapping. The three things that matter most:
- Systems — the actual named applications: SAP ECC, Salesforce, Snowflake, a homegrown microservice. Not "the CRM" — the specific product, because integration behaviour differs wildly between, say, Salesforce and a bespoke CRM.
- Connections — the mechanism data moves through: REST API, SFTP file drop, Kafka topic, IDoc, database replication. Label the arrow with the protocol, not just "sends data."
- Direction — does A push to B, does B poll A, or is it bidirectional? This is the detail most hand-drawn diagrams get wrong, and it's the detail that actually matters during an incident.
Building the diagram, step by step
- Start from the template. Open FlowDiagrams, then ☰ → Starter templates → Integration landscape. This drops in a working example — a source system, a gateway, and downstream consumers — that you can reshape rather than starting from a blank canvas.
- Swap in your real systems. Open the library panel (grid icon, top right) and search for your actual vendors — SAP, Oracle, Salesforce, Workday, whatever you run. There are 200+ built-in logos across ERP, SaaS, Data, BI, Cloud and Infra categories. Drag one onto the canvas to place it.
- Connect them with labelled arrows. Draw a connector between two systems and type the protocol directly on the line — "REST", "SFTP nightly", "Kafka: orders.created". FlowDiagrams routes new connectors with clean right-angle ("elbow") corners by default, which keeps a landscape with a dozen systems from turning into a spaghetti diagram.
- Show direction explicitly. Arrowheads default to one direction; for a genuinely bidirectional sync, add an arrowhead at both ends via the connector's style options in the side panel rather than leaving it ambiguous.
- Group by domain, not by chronology. Cluster systems by business domain (Finance, Order Management, Customer Data) using a frame/zone shape, rather than laying them out in the order you happened to add them. A reader scans by domain, not by your editing history.
- Export and share. ☰ → Export image / PDF… gives you PNG, SVG, or PDF. SVG is worth choosing if the diagram is going into a wiki or Confluence page someone might zoom into.
A common mistake: modelling systems instead of data flow
It's tempting to draw every system your company owns and call it an integration diagram. That's an inventory, not architecture. A useful integration diagram is scoped to one flow — "how an order gets from the webstore to the warehouse" — even if that means leaving out systems that aren't part of this particular journey. If you need the full inventory too, that's a second, separate diagram.
Keeping it current
Integration diagrams rot fast — a new API version, a retired middleware layer, and the diagram is wrong within a quarter. Two things make this less painful: export your diagram's underlying file (☰ → Save to file gives you a .flow.json) and keep it in the same repo as the integration code it documents, and if you're already using an AI coding assistant like Claude Code or Codex, FlowDiagrams' AI button (sparkle icon, top toolbar) gives you a skill file that lets the assistant regenerate the diagram directly from your codebase when things change.
Frequently asked questions
- What is an integration architecture diagram?
- A diagram showing how separate systems — ERPs, SaaS apps, databases, middleware — exchange data with each other: which system calls which, over what protocol (REST, SFTP, Kafka, IDoc…), and in which direction.
- Do I need special software to make one?
- No. Any tool with boxes and arrows technically works. What makes an integration diagram genuinely useful to a reader is recognisable vendor logos instead of generic rectangles — a box labelled "SAP" reads slower than the SAP icon itself.
- Is my architecture data uploaded anywhere?
- No. FlowDiagrams keeps diagrams only in your browser's local storage — there is no account, no server, and nothing is uploaded. That matters here specifically, since integration diagrams often reveal which vendors and internal systems you run.
Try it yourself
FlowDiagrams is free, works offline, and never uploads your diagram anywhere.
Open FlowDiagrams →