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Process data locally before sending it elsewhere

Process data locally by running Expanso Edge beside the data source and applying transformations before an output sends records elsewhere. This first run generates one synthetic sensor record, flags a temperature above 30°C, drops the raw diagnostic field, and prints the selected fields on your machine.

Run your first result​

You need Expanso Edge and the CLI installed and two terminals. No Cloud account or external data service is required. Use only synthetic data for this first check.

In terminal one, start a dedicated local node. Keep it open to see the output:

expanso-edge run --local --no-watch --api-listen 127.0.0.1:19031 --data-dir ./expanso-first-result-data

In terminal two, download and inspect the job, validate its pipeline configuration, then submit it explicitly to the local node:

curl -fsSLo process-locally.yaml https://examples.expanso.io/files/first-results/process-locally.yaml
cat process-locally.yaml
expanso-edge validate process-locally.yaml
expanso-cli --endpoint http://127.0.0.1:19031 job deploy process-locally.yaml

Validation checks pipeline syntax and components. Submission alone is not success: confirm the JSON result in terminal one.

The complete job​

The generated input is finite: one batch, then completion.

Download the job file 
name: first-result-process-locally
type: pipeline
config:
  input:
    generate:
      count: 1
      interval: 1s
      mapping: |
        root = {"sensor_id":"demo-sensor-1","site":"demo-lab","temperature_c":31.5,"raw_payload":"synthetic diagnostic bytes"}
  pipeline:
    processors:
      - mapping: |
          root.sensor_id = this.sensor_id
          root.site = this.site
          root.temperature_c = this.temperature_c
          root.alert = this.temperature_c > 30
  output:
    stdout:
      codec: lines

Input​

{
  "sensor_id": "demo-sensor-1",
  "site": "demo-lab",
  "temperature_c": 31.5,
  "raw_payload": "synthetic diagnostic bytes"
}

Expected output​

The local node prints the following JSON record alongside its service logs. JSON key order can differ.

{
  "alert": true,
  "sensor_id": "demo-sensor-1",
  "site": "demo-lab",
  "temperature_c": 31.5
}

This bounded job was executed with Expanso Edge 2.1.21 on September 10, 2026; the output matched this record. This proof covers local synthetic execution only.

If you do not see the result​

  • Connection refused: start the local node; check both ports match.
  • Port occupied: use another unused port in both commands.
  • No output: inspect terminal one for errors.
  • Rerun: change the completed job’s name before submitting again.

When finished, press Ctrl+C in terminal one to stop the local node. Its state remains in ./expanso-first-result-data; use a fresh directory for an independent later session.

What this proves, and what to check next​

This job generates synthetic data in memory and writes to local stdout. It does not connect to a real sensor, prove network isolation, implement durable buffering, or validate a production deployment. Where data goes is determined by the inputs, processors, and outputs you configure.

Common questions​

Do I need Expanso Cloud for this first run?​

No. Local mode accepts the job on a loopback API without a Cloud connection. Cloud setup is a separate next step for managing deployed nodes and jobs.

How do I move from this result to my own data?​

Start with a non-sensitive sample from the intended source. Define the selected fields and threshold behavior, then check normal, boundary, and malformed readings. Read the Local Mode Quick Start to extend this local workflow. Follow the Expanso Cloud Quickstart when you need managed nodes. Verify the real output destination after deployment.

Try another first result​