Introduction

What OpenCelium is

OpenCelium is an integration platform. You describe how APIs talk to each other — which calls to make, in which order, and how data maps between them — and OpenCelium runs it on a schedule or on demand. Everything is done through a web interface; you do not write integration code, though you can drop into a script where a transformation needs it.

A typical use: your CMDB holds the authoritative list of servers, your monitoring system needs to know about them. A workflow reads the objects from the CMDB, loops over them, and creates or updates the corresponding hosts in monitoring. A schedule runs it every night.

The pieces

Piece	What it is
Invoker	A definition of an API: its authentication and its operations. Written once per product. See Connectors and invokers.
Connector	One concrete system, using an invoker plus credentials. Production CheckMK is a connector.
Workflow	The integration itself: an ordered, branching sequence of steps, each calling a connector. See The workflow model.
Schedule	When a workflow runs — a cron expression, a manual start, or a webhook.
Notification	Who gets told, over e-mail or webhook, before/after/on failure.

The shortest possible path: create connectors for the two systems, build a workflow between them, attach a schedule.

What is new in 5.0

If you have used OpenCelium before, these are the changes that matter.

Connections became Workflows, and the two-connector limit is gone. Previously an integration had exactly one source and one target connector; touching a third system meant splitting it across several connections. Now every step names its own connector, so one workflow can call any number of systems in any order, including bidirectionally. This is a real model change, not a rename — The workflow model explains it.

Steps that are not connector calls. A Simple HTTP request step lets you call an endpoint directly, with your own method, URL, headers and body, without writing an invoker. A Trigger Workflow step starts another workflow’s schedule.

Live connector availability. Connector nodes show a status dot while you build, so an unreachable system is visible before the workflow goes to production.

A command palette. Ctrl+K anywhere: open lists, create and update entities, upload and download templates and invokers, or fuzzy-search the workflow you have open. See Command palette.

A rebuilt interface, on Ant Design, with a two-menu navigation, consistent lists and wizards, and light/dark themes throughout.

Server configuration from the UI. application.yml can be edited under License & System → Configurations, with comments preserved, secrets masked and automatic backups. See Configure the system.

System Check. One page reporting the health of OpenCelium, MariaDB, MongoDB, the mail server, the polyglot engine and the host.

A dashboard with history — seven days of executions and failures, live CPU and memory, top workflows by execution count.

Password reset, requested from the login page.

Upgrading from 4.x? Read Upgrading from 4.x before you start: your workflow documents are converted on read without being rewritten, but two application.yml keys moved and the frontend endpoint configuration changed.

Where to go next

• Quick install — get a server running.

• Your first workflow — build a working integration end to end.

• The workflow model — understand the model properly.