Output Monitoring

Your cron job didn't fail.
It lied.

It ran. It exited 0. It pinged on time. And it exported nothing, backed up nothing, synced nothing. Most tools call that a success. DeadManCheck checks whether your job actually produced valid results.

Start free → See quickstart

Standard monitoring

✓ ETL job ran at 03:00

✓ Exit code 0

✓ Ping received

Rows exported: 0 · upstream API returned empty

Alert sent: no

DeadManCheck

✓ ETL job ran at 03:00

✓ Exit code 0

✓ Ping received

rows_exported: 0 · assertion: rows > 0

⚠ Assertion failed — alert sent

The false success problem

Standard monitoring asks: did the job run? If yes, everything is fine. But that's the wrong question.

The right question is: did the job do what it was supposed to do?

⚠

Backup job ran but copied 0 files

Source directory was empty due to a misconfigured path. Exit 0. Ping sent. No backup taken.

⚠

ETL job completed but exported 0 rows

Upstream API returned an empty response due to an auth token expiry. The job handled it gracefully — and silently wrote nothing.

⚠

Sync job returned 200 but output was empty JSON

API returned {} instead of a populated payload. The script didn't error — it just synced nothing.

⚠

Nightly report ran but produced invalid output

A downstream schema change caused the report to generate malformed data — no errors thrown, no alert sent.

How DeadManCheck checks if your job actually worked

1. Send JSON output with your ping

# Bash

ROWS=$(run-etl-job.sh)

curl -s -X POST \

https://deadmancheck.io/ping/token/end \

-H "Content-Type: application/json" \

-d "{\"rows\": $ROWS}"

# Python

result = run_etl()

requests.post(

"https://deadmancheck.io/ping/token/end",

json={"rows": result.count,

"status": result.status}

)

2. Define assertions in the dashboard

Example assertions

rows > 0

status == "ok"

files_written >= 1

error_count == 0

If any assertion fails

Alert sent immediately — even though the job exited 0 and pinged on time.

Available on Developer and higher plans.

Why exit code 0 isn't enough

Exit codes communicate whether a process ran successfully — not whether it produced the right output. Most scheduled jobs are designed to handle empty responses, missing files, or API errors gracefully — which means they'll exit 0 even when nothing useful happened.

Exit code tells you

• The process started
• It didn't crash
• No unhandled exception

Exit code doesn't tell you

• How many rows were processed
• Whether output was valid
• Whether anything was written
• Whether downstream systems got data

Checking results tells you

• Exactly what your job produced
• Whether it meets your expectations
• Whether to trust the result

Monitor cron jobs that succeed but do nothing

If you're searching for cron job succeeded but did nothing, job ran but returned empty data, or how to validate cron job output — DeadManCheck is built for exactly this.

The problem has a name now: false success. Your job exits 0, your monitoring dashboard stays green, and your data pipeline silently stops working. It's the failure mode that standard monitoring tools were never designed to catch — because they only ask "did it run?", not "did it work?".

DeadManCheck introduces a new check: send your job's output as JSON with the ping, set rules on what valid output looks like, and get alerted the moment your job produces nothing useful.

DeadManCheck is the only cron monitoring tool that does this

Output monitoring is a new category. No other tool has it.

Healthchecks.io and Cronitor both monitor whether jobs run and whether they run on time. Neither can tell you what the job produced. If your backup copied 0 files or your ETL exported 0 rows, they stay green. DeadManCheck doesn't.

Capability	DeadManCheck	Healthchecks.io	Cronitor
Missing ping alert	✓	✓	✓
Duration monitoring	✓ automatic	Manual grace period	Manual only
Output assertions unique	✓	✗	✗
JSON output validation	✓	✗	✗
Open source	✓	✓	✗