Papertrail is described as 'Hosted log management for servers, apps, and cloud services. Papertrail aggregates syslog, Text log files, Apache, MySQL, cloud hosting, Ruby on Rails, Windows events, Tomcat, Heroku apps, and routers & firewalls' and is a web log analyzer in the network & admin category. There are more than 25 alternatives to Papertrail, not only websites but also apps for a variety of platforms, including Linux, Windows, Mac and Self-Hosted apps. The best Papertrail alternative is Better Stack Telemetry. It's not free, so if you're looking for a free alternative, you could try Grafana or Graylog. Other great sites and apps similar to Papertrail are Datadog, Fluentd, Prometheus and Kibana.
The big problem of comparison; Papertrail is web based and logsniffer is a self-hosted, standalone application.