Six products. Three release lines.
HotLoop is six products for the plant floor: four that grow with a site (IoT, Edge, Gateway, Edge Relay), plus Flow for wiring and Cascade for workflows. The four share one codebase and one version, and every one of them speaks every protocol, MQTT included, so what you're really picking is how much of the plant the box has to run.
HotLoop core line, 4.18.10 One codebase and one version. IoT to Edge to Gateway is the path a site grows along, and Edge Relay is the headless forwarder beside them.
Flow line, 2.2.0 Its own release line, running next to HotLoop.
Cascade line, 0.1.2 Its own release line, running next to HotLoop.
Side by side
What each product has, not whether it's finished. For that, open the product's page: every piece on it says whether it ships today, is unverified, or hasn't been built.
| Feature | IoT | Edge | Gateway | Edge Relay |
|---|---|---|---|---|
| Every protocol driver, MQTT included | Yes | Yes | Yes | Yes |
| Entities, automations, helpers, scripts, logbook | Yes | Yes | Yes | No |
| Notifications and ISA-18.2 alarms | Yes | Yes | Yes | No |
| MCP for agents | Yes | Yes | Yes | No |
| MQTT discovery (Shelly, ESPHome, Tasmota, Zigbee2MQTT), read and forward only on the relay | Yes | Yes | Yes | Yes |
| Network discovery (mDNS, SSDP, DHCP) | Yes | Yes | Yes | No |
| Historian targets in the plant's own database | Yes | Yes | Yes | No |
| UniFi network driver, read-only (the screens and events need the UI) | Yes | Yes | Yes | Yes |
| Backups and restore | Yes | Yes | Yes | No |
| Dashboards, per role and per screen, with panel mode | Yes | Yes | Yes | No |
| Store-and-forward over Sparkplug B | No | Yes | Yes | Yes |
| OPC UA server | No | Yes | Yes | No |
| Fleet management of edge relays | No | No | Yes | No |
| Multi-site roll-ups | No | No | Yes | No |
| Scheduled reports | No | No | Yes | No |
| A web UI and a login | Yes | Yes | Yes | No |
| Database | SQLite or PostgreSQL | SQLite, PostgreSQL or TimescaleDB | SQLite, PostgreSQL or TimescaleDB | None |
| Install today | Yes | Yes | Yes | Yes |
Moving up keeps your data
Every product runs the same schema. Going from IoT to Edge to the Gateway is designed to be an image swap on the same database, with your devices, entities, rules, alarms, history and users already there. Going back down deletes nothing: what the smaller product doesn't have just sits there until you come back. The point: outgrowing the Pi is supposed to cost you an image pull, not a migration project. The Quadlet move has been run, IoT to Edge to the Gateway on one database volume. The same move as a Helm upgrade on a real cluster, and going back down a product, has not, so don't take a box you care about down.
No keys, no tiers
No license keys, and nothing unlocks at runtime. The product is what got compiled, so a feature that isn't in your image can't be flipped on by accident, and nobody can flip one off to squeeze you later. All of HotLoop is under one license, the HotLoop Business Source License 1.1: free for home and lab, free for business through EmberNET. What that means for you.
Where each one is headed: the HotLoop roadmap for the four core products, the Flow roadmap and the Cascade roadmap. The docs for all six are at docs.hotloop.io.