Draw it. Explain it. Change it. Run it.

Obelisk keeps one model of your architecture. Diagrams are views of it, flows tell stories on them, and simulations test it. Drafts let you propose a change before you make it.

Request access How Obelisk differs

The Obelisk Landscape Map with Order service selected: what it connects to stays lit while the rest fades — The Landscape Map with Order service selected. What it touches stays lit; the rest fades back.

Draw it: one shared model

Obelisk stores objects (apps, stores, queues, people) and the connections between them. A diagram is a view onto that model, so the same object can sit on every diagram and never drift.

Nest objects as deep as your system goes, and open any one to look inside.
Works the way you already draw C4, without the four-level cap. See how.
Start with the built-in types, then add your own, with a name, icon, colour and shape.
Give each object an owning team, tags and technologies. Mark lifecycle with the Planned, Deprecated and Removed tags.
Press Ctrl/Cmd+K to jump to any object, connection, diagram or flow.

Obelisk object types: application, store, queue, server, event stream, actor, boundary, component and mobile app, each with an icon and shape — Object types are your organization's vocabulary. Rename them, restyle them, add your own.

Explain it: flows that play back

A flow walks one request through the system, step by step. Branch it into alternate and parallel paths for the "what if it fails?" cases, link subflows for the details, then play it back like a slideshow.

Flows use the same objects as your diagrams. Export one as Mermaid, PlantUML or plain text for your docs.

Obelisk flow editor for Dispatch a courier, with two parallel paths, beside the Delivery diagram — The Dispatch a courier flow: messages, a process, a note, then two paths at once.

Explain why: comments and decisions

Comments pin to the spot on the canvas they're about, with threads and @-mentions. Mark one as a question, an idea or an inaccuracy, and resolve it when it's handled.

Decision records keep the why, with a status timeline and links to diagrams, drafts, objects, connections and other decisions. Approved and superseded ones lock.

A question comment thread pinned beside Orders DB on the Obelisk diagram canvas, with a reply — A question asked on the diagram, answered in the thread next to it.

Change it: drafts and snapshots

Propose a change as a draft. It opens on the real map, with a list of every change and who proposed it. When it merges, Obelisk checks for conflicts with anything that changed in the meantime.

Snapshots freeze the whole landscape. Browse any one, or roll back to it.

The review of a Obelisk draft named Async checkout: its 6 changes field by field (3 created, 2 updated, 1 deleted) and a Merge button — A draft that adds an order queue: 6 changes to review, ready to merge.

Run it: simulation

This is the part other architecture tools don't have. Put small rules on objects, a few lines of JavaScript each, then send a steady stream, a spike or a ramp of traffic through the model.

Put a rule on a technology, like Postgres, and every Postgres gets it.
Nodes change colour and fill their meters as the run plays.
Every dropped message has a trace: each rule it met, in order.
Same seed, same run. Everyone replays the same failure.

Obelisk sends traffic through your model and shows where it breaks.

Take it anywhere

Export a diagram as PNG or SVG for a slide. Export the whole model as JSON or CSV for a script.

Or export it as llms.txt, so an AI assistant reads your real architecture instead of guessing.

The Obelisk export dialog listing SVG, PNG, CSV, JSON and LLMs.txt — Five ways out, from the same dialog.

Built to live inside your company

Single sign-on: SAML and OIDC, with IdP groups mapped to roles. Passwords as a fallback.
Roles and access: Admin, editor and viewer, with access limited to chosen landscapes.
API and webhooks: A REST API with scoped keys, and signed webhooks when the model changes.
Import: Bring a model in as YAML or JSON, from a file or a script.
Share links: Read-only links with an optional password. Viewers can even run the simulations.
Audit log: Every change, and who made it: a person or an API key, by name. Export it as CSV.

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