# Hardware apps

**Hardware apps — start here**

The three shapes a FlowFuse app takes when it runs on a device. Pick by how much varies per site: nothing (Packaged App), a few settings (Configurable App), or you assemble it yourself (Edge Building Block).

<guide-tabs>
<guide-tab label="Packaged App">
<flow-diagram :edges="[{"from":"snap","to":"inst","label":"deploy · sealed","accent":"slate"}]" :nodes="[{"id":"snap","label":"Pipeline snapshot","sub":"sealed · built once","accent":"indigo"},{"id":"inst","label":"Remote Instance","sub":"identical","accent":"indigo","many":true}]">



</flow-diagram>

A sealed product that ships on a piece of hardware and is identical everywhere — buy it, it runs on its device, nothing to configure.

**Use it when** — The app ships with a known partner device and the data it reads is fixed by that hardware.

**How it works** — Built and promoted through a pipeline (dev → staging → prod), then deployed to a Remote Instance as a snapshot. Everything is baked in; only fixed env vars vary at deploy.

**Major components**

- **Pipeline snapshot** — the app built once, promoted to the device
- **Remote Instance (edge device)** — FlowFuse-managed Node-RED running the sealed app
- **Team Broker (MQTT)** — carries the app's events to subscribers
- **FlowFuse Tables** — stores the rows the app writes

**Where config & data live**

- **Config** — baked into the snapshot; only fixed env vars at deploy, nothing per-site.
- **Data** — events to the Team Broker, records to FlowFuse Tables.

</guide-tab>

<guide-tab label="Configurable App">
<flow-diagram :edges="[{"from":"snap","to":"inst","label":"same build","accent":"slate"},{"from":"cfg","to":"inst","label":"loads its own config","accent":"red","dashed":true}]" :nodes="[{"id":"snap","label":"Pipeline snapshot","sub":"same build","accent":"indigo","col":1,"row":1},{"id":"cfg","label":"Per-site config","sub":"tags · broker · site","accent":"slate","col":1,"row":2},{"id":"inst","label":"Remote Instance","sub":"per site","accent":"indigo","many":true,"col":2,"row":1}]" :legend="[{"line":"slate","label":"same build"},{"line":"red","dashed":true,"label":"loads its own config"}]">



</flow-diagram>

The same shelf product, plus a few knobs — tag names, broker address, site name — that differ per site and live on the Remote Instance.

**Use it when** — The flows are the same everywhere but the values they use differ per install and may change over time.

**How it works** — Same pipeline delivery to a Remote Instance; the runtime loads a per-site config from a file on the device. Back that file up to the database, so a device swap restores the config — the device is the source of truth, the DB is the safety net.

**Major components**

- **Pipeline snapshot** — the same build promoted to every device
- **Remote Instance (edge device)** — runs the app and loads its own per-site config
- **Per-site config (tags · broker · site)** — a file on the device, backed up to the DB
- **Team Broker / FlowFuse Tables** — event egress + records

**Where config & data live**

- **Config** — a per-site file on the device (tags, broker address, site name), backed up to FlowFuse Tables so a swap restores it.
- **Data** — Team Broker + FlowFuse Tables.

</guide-tab>

<guide-tab label="Edge Building Block">
<flow-diagram :edges="[{"from":"eq","to":"inst","label":"reads"},{"from":"inst","to":"broker","label":"publishes","accent":"slate"}]" :nodes="[{"id":"eq","label":"Equipment","sub":"signals / PLC","accent":"slate"},{"id":"inst","label":"Remote Instance","sub":"edge building block","accent":"indigo"},{"id":"broker","label":"Team Broker","sub":"MQTT","accent":"indigo"}]">



</flow-diagram>

Not a finished app — one hardware-facing block plus example flows, running on a Remote Instance. You assemble everything upstream of it yourself.

**Use it when** — The hardware-facing piece is reusable, but everything before it differs so much per site that no finished app would fit.

**How it works** — Blocks are published as subflows to the Team Library with an example flow. Consumers drop them onto a Remote Instance and wire them up.

**Major components**

- **Equipment (signals / PLC)** — the source hardware the block reads
- **Remote Instance (edge device)** — runs the edge building block at the line
- **Team Broker (MQTT)** — publishes the normalized data upstream
- **Team Library** — where the block is published as an installable subflow

**Where config & data live**

- **Config** — lives in the consuming flow you build around the block (env / context).
- **Data** — Team Broker (normalized, upstream).

</guide-tab>
</guide-tabs>