An Elixir Logger backend for Logflare. Streams logs to the Logflare.app API.


Get your api_key and create a source at logflare.app

You will need a Logflare source source_id which you can copy from your dashboard after you create a one.

config :logger,
  level: :info, # or other Logger level
  backends: [LogflareLogger.HttpBackend]

config :logflare_logger_backend,
  url: "https://api.logflare.app", # https://api.logflare.app is configured by default and you can set your own url
  level: :info, # Default LogflareLogger level is :info. Note that log messages are filtered by the :logger application first
  api_key: "...", # your Logflare API key, found on your dashboard
  source_id: "...", # the Logflare source UUID, found  on your Logflare dashboard
  flush_interval: 1_000, # minimum time in ms before a log batch is sent
  max_batch_size: 50, # maximum number of events before a log batch is sent
  metadata: :all # optionally you can drop keys if they exist with `metadata: [drop: [:list, :keys, :to, :drop]]`

Alternatively, you can configure these options in your system environment. Prefix the above option names with LOGFLARE_.

export LOGFLARE_URL="https://api.logflare.app"
export LOGFLARE_API_KEY="..."


After configuring LogflareLogger in config.exs, use Logger.info, Logger.error, ... functions to send log events to Logflare app.

Usage with context

LogflareLogger.context function signatures follows the one of Logger.metadata with slight modifications to parameters and return values.

# Merges map or keyword with existing context, will overwrite values.
LogflareLogger.context(%{user: %{id: 3735928559}})
LogflareLogger.context(user: %{id: 3735928559})

# Get all context entries or a value for a specific key

# Deletes all context entries or specific context key/value
LogflareLogger.context(user: nil)

Current limitations

Logflare log event BigQuery table schema is auto-generated per source. If you send a log with Logger.info("first", user: %{id: 1}), Logflare will generate a metadata field of type integer. If in the future, you'll send a log event to the same source using Logger.info("first", user: %{id: "d9c2feff-d38a-4671-8de4-a1e7f7dd7e3c"1}), the log with a binary id will be rejected.

LogflareLogger log payloads sent to Logflare API are encoded using BERT.

At this moment LogflareLogger doesn't support full one-to-one logging of Elixir types and applies the following conversions:

  • atoms converted to strings
  • charlists are converted to strings
  • tuples converted to arrays
  • keyword lists converted to maps
  • structs converted to maps
  • NaiveDateTime and DateTime are converted using the String.Chars protocol
  • pids are converted to strings

LogflareLogger doesn't support:

  • non-binary messages, e.g. Logger.info(%{user_count: 1337})


LogflareLogger automatically logs all exceptions and formats stacktraces.


Run mix logflare_logger.verify_config to test your config.

Email support@logflare.app for help!


If available in Hex, the package can be installed by adding logflare_logger_backend to your list of dependencies in mix.exs:

def deps do
    {:logflare_logger_backend, "~> 0.11.0"}

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/logflare_logger_backend.