Log Formatting

Message Formatting

Your log data must not contain any personal data, such as names, email addresses, etc. It is your responsibility to ensure this data is filtered out before being sent to AppSignal, and when identifying a person is necessary that your application uses alternative forms of identification such as a user ID, hash, or pseudonym.

Supported Log Formats

How you can format your logs will vary depending on which configuration you are using with Logging. The table below outlines the currently available configurations and the log formats which they support

AWS Kinesis / CloudWatch
Clever Cloud
Gigalixir Log Drain
Heroku Log Drain

Fixed-format endpoint

We have one special endpoint/source, and that's the http-json endpoint. This endpoint is intended for customers implementing their own log forwarding solution, or log implementation. This endpoint expects a specific NDJSON format, and will silently ignore any messages that do not match this format.


When using Logfmt or JSON as your log format, you can add searchable attributes to your logs. Attributes can be any of the following types:

  • string
  • integer (e.g. 10)
  • double (e.g. 10.01)
  • boolean (true/false)


When specifying Plaintext as your log format, the log line will be used as the message as-is, and AppSignal will not parse attributes from the log line. If you want to have searchable attributes in your application's logs, we recommend formatting your logs in Logfmt or JSON.