List of free monitoring stuff for developerππ½
If you're looking for all programming tools around monitoring (not just free). Check this page List of monitoring Programming Tools
Sentry
Self-hosted and cloud-based application monitoring that helps software teams discover, triage, and prioritize errors in real-time.
Tag: status, monitoring, logging
1 User 30 day data retention 5K errors 10K transactions 1GB attachments

NetData
Monitor everything in real time. Troubleshoot slowdowns and anomalies in your infrastructure with thousands of per-second metrics, meaningful visualizations, and insightful health alarms with zero configuration.
Tag: monitoring
Open Source

Sumo Logic
Sumo Logic provides best-in-class cloud monitoring, log management, Cloud SIEM tools, and real-time insights for web and SaaS based apps.
Tag: monitoring
Log Analytics 500MB/day Community Support

Checkly
Checkly is the API & E2E monitoring platform for the modern stack: programmable, flexible and loving JavaScript.
Tag: monitoring
50k API check runs/mo 5k browser check runs/mo 5 users, basic features

Monika - Free and Open Source Synthetic Monitoring Tool
Free and Open Source Synthetic Monitoring Tool
Tag: monitoring

Datadog
Datadog is the essential monitoring and security platform for cloud applications
Tag: log-management, monitoring, security
Core collection and visualization features 1-day metric retention Up to 5 hosts

Browse AI
Monitor any webpage for changes. Download any data on the web as a spreadsheet. Turn any website into an API.
Tag: scraping, monitoring
1 Task Works on Most Websites 24 Hour Checks 1 Minute Per Execution 14-Day Retention

Allma
Don't just manage your incidents, collaborate on them with the entire company. Manage alerts, tickets, and timelines of events all from within the comfort of your Slack instance.
Tag: monitoring, status
Unlimited Users Slack Powered Incident Workflows 7 Day Data Retention

LogRocket
LogRocket helps you understand problems affecting your users, so that you can get back to building great software.
Tag: monitoring, logging
Includes 1,000 sessions / month 1-month data retention