How do I set up Raven.cr with my Kemal app?

Add Raven.cr to your shard.yml, require it in your code, and set the SENTRY_DSN environment variable. The README mentions built-in Kemal integration, which automatically hooks into the framework's error handling without extra code.

Can Raven.cr handle background job errors in Sidekiq.cr?

Yes, it has built-in Sidekiq.cr support. The async configuration example shows how to enqueue error events as jobs, ensuring errors from workers are captured without blocking the job queue.

What data does Raven.cr scrub by default to protect privacy?

By default, it removes sensitive information like credit card or Social Security numbers, and does not report POST, PUT, PATCH data or cookies. You can customize processors for more control, as per the README's reference to Sentry documentation.

Raven.cr vs official Sentry SDKs: which should I use?

For Crystal apps, Raven.cr is the only Sentry option since there's no official SDK. In other languages, official SDKs offer better support, but Raven.cr effectively fills this gap with feature parity and framework integrations.

How to capture unhandled exceptions in a Crystal CLI tool with Raven.cr?

Use the crash handler binary by building it with shards and running your tool through it. The README details compiling sentry.crash_handler and executing it with your app to catch crashes like segfaults.

Does Raven.cr slow down my Crystal application?

Not significantly, thanks to async support. Events can be sent in background fibers or jobs, minimizing impact on the main thread, and configuration allows tuning for performance-critical environments.

raven.cr — Crystal Client for Sentry

What is raven.cr?

Raven.cr is an unofficial Crystal client for Sentry, a popular error tracking and monitoring platform. It allows Crystal developers to capture exceptions, log events, and send them to Sentry for real-time debugging and performance monitoring. The library integrates seamlessly with Crystal's logging system and popular web frameworks.

Target Audience

Crystal developers building web applications or services who need robust error tracking and monitoring capabilities. It's particularly useful for teams using frameworks like Kemal, Amber, or Lucky.

Value Proposition

Developers choose Raven.cr because it provides a native, feature-complete Sentry client for Crystal, with framework integrations, async support, and a dedicated crash handler—filling a gap in the Crystal ecosystem for professional error monitoring.

Raven is a Crystal client for Sentry

Use Cases

Best For

Adding error tracking to Crystal web applications
Monitoring production crashes in Kemal or Amber apps
Capturing and debugging exceptions in background jobs with Sidekiq.cr
Enriching log data with user context and breadcrumbs
Handling unhandled exceptions and segfaults in Crystal binaries
Integrating Sentry with Crystal's built-in Log infrastructure

Not Ideal For

Teams requiring official Sentry support with guaranteed updates and direct vendor assistance
Projects operating in highly regulated environments where external data transmission must be minimized or audited extensively
Applications with extremely lightweight error handling needs that can be satisfied by Crystal's built-in exception logging

Pros & Cons

Pros

Framework Integrations

Built-in support for Kemal, Amber, Lucky, Sidekiq.cr, and action-controller, allowing seamless error tracking in popular Crystal ecosystems without custom glue code.

Async Event Handling

Configurable async callbacks enable non-blocking error reporting, with examples for background jobs like Sidekiq.cr to maintain application performance.

Crash Handler for Reliability

External binary crash handler captures unhandled exceptions and segfaults, addressing a gap in Crystal's native error handling for production robustness.

Log Backend Integration

Dedicated Log backend intercepts Crystal's standard log entries to record breadcrumbs or capture exceptions, enhancing debugging with minimal code changes.

Environment-Safe Configuration

Automatically activates only when SENTRY_DSN is set, preventing accidental error reports in development and simplifying environment-based setup.

Cons

Unofficial Client Limitations

As a community-maintained project, it may not keep pace with Sentry's official SDK updates, potentially missing new features or timely security patches.

Crash Handler Deployment Complexity

Requires compiling and running a separate binary wrapper, adding steps to the build and deployment process compared to integrated solutions.

Default Data Scrubbers Omit Context

Sensitive data like POST bodies and cookies are not reported by default, which might hinder debugging unless explicitly configured, as noted in the README.

Frequently Asked Questions

What is raven.cr?

Target Audience

Crystal developers building web applications or services who need robust error tracking and monitoring capabilities. It's particularly useful for teams using frameworks like Kemal, Amber, or Lucky.

Value Proposition

Use Cases

Best For

Adding error tracking to Crystal web applications
Monitoring production crashes in Kemal or Amber apps
Capturing and debugging exceptions in background jobs with Sidekiq.cr
Enriching log data with user context and breadcrumbs
Handling unhandled exceptions and segfaults in Crystal binaries
Integrating Sentry with Crystal's built-in Log infrastructure

Not Ideal For

Teams requiring official Sentry support with guaranteed updates and direct vendor assistance
Projects operating in highly regulated environments where external data transmission must be minimized or audited extensively
Applications with extremely lightweight error handling needs that can be satisfied by Crystal's built-in exception logging

Pros & Cons

Pros

Framework Integrations

Built-in support for Kemal, Amber, Lucky, Sidekiq.cr, and action-controller, allowing seamless error tracking in popular Crystal ecosystems without custom glue code.

Async Event Handling

Configurable async callbacks enable non-blocking error reporting, with examples for background jobs like Sidekiq.cr to maintain application performance.

Crash Handler for Reliability

External binary crash handler captures unhandled exceptions and segfaults, addressing a gap in Crystal's native error handling for production robustness.

Log Backend Integration

Dedicated Log backend intercepts Crystal's standard log entries to record breadcrumbs or capture exceptions, enhancing debugging with minimal code changes.

Environment-Safe Configuration

Automatically activates only when SENTRY_DSN is set, preventing accidental error reports in development and simplifying environment-based setup.

Cons

Unofficial Client Limitations

As a community-maintained project, it may not keep pace with Sentry's official SDK updates, potentially missing new features or timely security patches.

Crash Handler Deployment Complexity

Requires compiling and running a separate binary wrapper, adding steps to the build and deployment process compared to integrated solutions.

Default Data Scrubbers Omit Context

Sensitive data like POST bodies and cookies are not reported by default, which might hinder debugging unless explicitly configured, as noted in the README.

Frequently Asked Questions

raven.cr

What is raven.cr?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

raven.cr

What is raven.cr?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?