AppSignal
https://appsignal.com
Amsterdam, Netherlands
2013
appsignal
Making the Most of Your Logs in Rails
  |  By Hans-Jörg Schnedlitz
Rails logs through Rails.logger — on Rails 8.1, a BroadcastLogger that writes tagged lines to STDOUT in production and to log/development.log in development. Six levels exist: debug, info, warn, error, fatal, and unknown; production defaults to info via RAILS_LOG_LEVEL. Good log messages are descriptive, carry context like request IDs, and become structured JSON when machines read them.
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Generating Random Numbers in Ruby: rand, Random & SecureRandom
  |  By Joyce Echessa
To generate a random number in Ruby, call rand: rand(10) returns an integer from 0–9, rand(1..10) an integer from 1–10, and rand alone a float between 0.0 and 1.0. For security-sensitive values like tokens and passwords, use SecureRandom — rand is predictable. Computers cannot produce truly random numbers by computation alone. A deterministic machine can only produce pseudorandom numbers: a stream that looks random but comes from an algorithm fed with a starting value, the seed.
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How to Use Shoulda Matchers with RSpec for Ruby on Rails
  |  By Kingsley Chijioke
shoulda-matchers gives you one-line RSpec and Minitest matchers for common Rails behavior — it { should validate_presence_of(:name) } replaces a hand-written validation spec. Add gem "shoulda-matchers", "~> 8.0" to your Gemfile’s test group, then add the configuration block to spec/rails_helper.rb naming your test framework and library. Version 8 works with Rails 8.1 and rspec-rails 8.
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Sidekiq for Ruby on Rails: Setup, Jobs & Monitoring (2026)
  |  By Jeff Morhous
Sidekiq is a background job framework for Ruby that processes jobs concurrently on threads, backed by Redis. In Rails, add gem "sidekiq", set config.active_job.queue_adapter = :sidekiq, enqueue with perform_async, and run the sidekiq process alongside your app server. Sidekiq 8 requires Ruby 3.2+ and Redis 7+. That answer covers the mechanics.
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Custom Exceptions in Ruby: Classes, Messages & Hierarchies
  |  By Brena Monteiro
To create a custom exception in Ruby, define a class that inherits from StandardError: class PaymentError < StandardError; end. Raise it with raise PaymentError, "card declined" and rescue it by class. Inherit from StandardError, not Exception, so a bare rescue still catches it. Pass a default message by overriding initialize and calling super. Ruby’s built-in exception classes describe the language’s failure modes, not your application’s.
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Devise for Ruby on Rails: Setup, Modules & Rails 8 Auth
  |  By Aestimo Kirina
Devise is a full-featured authentication gem for Ruby on Rails, built on Warden. It provides registration, login, password recovery, session timeout, and account locking via 10 composable modules. Install it with bundle add devise, then run rails g devise:install and rails g devise User. It works with Rails 7 and 8; Rails 8's built-in generator covers only simpler needs.
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Handling Exceptions in Grape for Ruby: rescue_from and error!
  |  By Kingsley Chijioke
Grape handles exceptions with rescue_from blocks declared on your API class: rescue_from :all catches every exception, while rescue_from ActiveRecord::RecordNotFound targets one class. Inside an endpoint, error!("Not Found", 404) halts with a formatted error, defaulting to status 500. Without a handler, invalid params return 400 and other exceptions bubble up to Rack. This guide covers Grape 3.3. Every response body, status code, and error message was verified on Grape 3.3.5, Rack 3.2.7, and Ruby 3.4.10.
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Add an App With Your Coding Agent
  |  By Serena Chou
You can now ask your coding agent to set up AppSignal in your application. Give it a prompt, let it follow the installation instructions, and watch a checklist fill in as data starts arriving. Installing AppSignal was already straightforward, but it still meant checking your environment, adding the right integration, creating an app, handling credentials, and confirming that telemetry arrived. These are useful checks, but they don't all need your attention.
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Rails 8 Guide: Features, Requirements & Upgrade Path (2026)
  |  By Damilola Olatunji
Rails 8.0 shipped November 7, 2024 and requires Ruby 3.2.0+. Headline features: a built-in authentication generator, Solid Queue/Cache/Cable (database-backed, no Redis), Kamal 2 + Thruster deployment, Propshaft, and production-ready SQLite. Rails 8.1 (October 2025) is the current release; Rails 8.0 now gets security fixes only, through November 2026. This guide walks through each Rails 8 feature with the commands and defaults you’ll use.
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appsignal
Top 17 AI Testing Tools
  |  By Faith Kovi
Generating tests isn’t the hard part anymore. Ask an LLM to create Playwright tests, and it will produce hundreds of them in no time. The problem lies in deciding whether those tests are useful, maintaining them as your application changes, and knowing if you’ve even chosen the right tool in the first place. This article compares 17 AI testing tools across 5 categories. We’ll look at what each of them does, where it fits, what makes it different, and where it falls short.
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Made for teams that want to build high quality Ruby and Elixir applications, AppSignal offers amazing insights into errors and performance issues, plus host monitoring and an easy to use custom metrics platform.

AppSignal supports the Elixir language with an Elixir package. The package supports pure Elixir applications and frameworks including Phoenix, Plug & Erlang.

AppSignal supports the Ruby language with a Ruby gem. The gem supports many frameworks and gems including Capistrano, DataMapper, Delayed Job, Grape, MongoDB, Padrino, Rack, Rake, Resque, Ruby on Rails, Sequel, Shoryuken, Sidekiq, Sinatra & Webmachine.

AppSignal now supports Node.js! The package supports pure JavaScript applications and TypeScript applications, and can auto-instrument various frameworks and packages with optional plugins.

AppSignal also has amazing support for catching errors from Front-end JavaScript applications and sending them to AppSignal, including the React, Vue, Angular, Ember, Preact & Stimulus frameworks.

Packed with features:

  • Alerts in your tools: AppSignal integrates with Slack, Flowdock, HipChat, OpsGenie and more.
  • Control your notifications: AppSignal notifies you exactly when you want to. Get the first exceptions per deploy, all of them of never. Set thresholds for performance notifications.
  • Amazing support: We don't do "first line" and "second line" support: you get to speak with a developer, immediately.
  • Send to issue trackers: A single click creates an issue with all the necessary details in your issue tracker of choice.
  • Manage teams and users: Add users to teams and give them access to specific or all, existing and/or new applications you monitor.
  • Focus on design: Developer tools do not need to be complicated and ugly. Our interface is kept clean and easy to use.

Catch errors, track performance, monitor hosts, detect anomalies — all in one tool.

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