Sentry SDK Playground

A multi-mode testing platform for Sentry SDK features across 12 languages

Overview

Learn by doing. The SDK Playground is a comprehensive testing platform for Sentry SDK features. Test event transformation callbacks, sampling strategies, filter patterns, webhook integrations, and configuration analysis—all in a safe sandbox environment. With 9 specialized testing modes, 50+ pre-built examples, and support for 12 SDK languages, you can master Sentry integration patterns before touching production.

Key Capabilities:

• 9 Testing Modes - Before Send, Fingerprinting, Before Send Transaction, Before Breadcrumb, Traces Sampler, Pattern Tester, Config Analyzer, API Query Tester, Webhooks
• 12 SDK Languages - JavaScript, Python, Ruby, PHP, Go, .NET, Java, Android, Cocoa, React Native, Rust, Elixir
• 50+ Example Templates - Real-world patterns for PII scrubbing, sampling, filtering, and more
• Visual Diff Viewer - Side-by-side comparison of original vs transformed data
• Real-time Validation - Catch syntax errors before execution
• Secure Sharing - Share configurations with automatic PII scrubbing

Quick Start

Requirements: Docker & Docker Compose (that's it!)

# 1. Clone and navigate to the repository
cd sdk-playground

# 2. Build and start all services
docker-compose up -d

# 3. Open the playground
open http://localhost:3000

The playground will be available at http://localhost:3000

Choose Your Mode

Mode	Purpose	Use When
Before Send	Transform error events	Scrubbing PII, adding tags, filtering errors
Fingerprinting	Control issue grouping	Normalizing dynamic data, custom grouping rules
Before Send Transaction	Transform performance data	Filtering health checks, adding context
Before Breadcrumb	Filter navigation/console logs	Reducing noise, scrubbing URLs
Traces Sampler	Dynamic sampling rates	Cost optimization, critical endpoint prioritization
Pattern Tester	Test filter patterns	Validating ignoreErrors/denyUrls
Config Analyzer	Validate SDK configuration	Reviewing Sentry.init() setup
API Query Tester	Test search queries	Building API integrations
Webhooks	Test webhook integrations	Debugging signature verification

Mode Overview

Before Send Mode

Transform error events before they are sent to Sentry. Use it to:

• Scrub PII (emails, IPs, tokens)
• Add custom tags and context
• Filter noisy errors
• Modify exception values

Example:

(event, hint) => {
  // Redact sensitive user data
  if (event.user?.email) {
    event.user.email = '[REDACTED]';
  }
  return event;
}

Fingerprinting Mode

Control how Sentry groups errors into issues. This is a convenience mode for testing fingerprinting via beforeSend. Use it to:

• Normalize dynamic data (user IDs, database instances)
• Group similar errors together
• Split overly-broad groupings by context

Example:

(event, hint) => {
  // Group all database errors together regardless of instance
  if (event.message?.includes('Database connection failed')) {
    event.fingerprint = ['database-connection-error'];
  }
  return event;
}

Before Send Transaction Mode

Transform transaction events before sending. Use it to:

• Drop health check transactions
• Add business context
• Modify transaction names
• Filter by endpoint

Example:

(transaction, hint) => {
  // Drop health check transactions
  if (transaction.transaction === 'GET /health') {
    return null;
  }
  return transaction;
}

Before Breadcrumb Mode

Filter and modify breadcrumbs before they're added to events. Use it to:

• Drop noisy console logs
• Scrub tokens from URLs
• Categorize breadcrumbs
• Reduce breadcrumb volume

Example:

(breadcrumb, hint) => {
  // Drop console breadcrumbs
  if (breadcrumb.category === 'console') {
    return null;
  }
  // Scrub tokens from navigation URLs
  if (breadcrumb.data?.to) {
    breadcrumb.data.to = breadcrumb.data.to.replace(/token=[^&]+/, 'token=[REDACTED]');
  }
  return breadcrumb;
}

Traces Sampler Mode

Implement dynamic sampling strategies for performance monitoring. Use it to:

• Sample critical endpoints at higher rates
• Drop health checks entirely
• Implement user-based sampling
• Optimize tracing costs

Example:

(samplingContext) => {
  const name = samplingContext.transactionContext.name;

  // Always sample payment endpoints
  if (name.includes('/payment')) {
    return 1.0; // 100%
  }

  // Never sample health checks
  if (name === 'GET /health') {
    return 0.0; // 0%
  }

  return 0.1; // 10% default
}

Output: Visual sampling rate indicator showing the percentage and what portion of transactions will be sent vs dropped.

Webhooks Mode

Test Sentry webhook payloads with HMAC-SHA256 signature generation and verification. Use it to:

• Debug webhook integrations
• Test signature verification code
• Inspect webhook payload structures
• Demonstrate webhook security to customers

Available Templates:

• Issue Alert - Created/Resolved/Assigned
• Metric Alert
• Error Event
• Comment Created

Config Analyzer Mode

Analyze and validate Sentry.init() configurations. Use it to:

• Validate configuration syntax
• Understand what each option does
• Get SE-focused recommendations
• Identify potential issues

Supported SDKs: JavaScript, Python, Ruby, PHP, Go, .NET, Java, Android, Cocoa

API Query Tester Mode

Test and validate Sentry API search queries. Use it to:

• Validate query syntax in real-time
• Get property suggestions for typos
• Execute queries against real data
• Generate ready-to-use cURL commands

Example Queries:

is:unresolved level:error
assigned:me
level:fatal age:-24h
!user.email:*@internal.com

Pattern Tester Mode

Test ignoreErrors, denyUrls, and allowUrls filter patterns. Use it to:

• Validate regex patterns before deployment
• Test patterns against sample inputs
• Generate Sentry.init() configuration code
• Understand pattern matching behavior

Pattern Types:

• ignoreErrors - String/regex patterns for error messages
• denyUrls - URL patterns to exclude from error reporting
• allowUrls - URL patterns to include (whitelist mode)

Supported SDKs

SDK	Language	Real-time Validation	Compilation
JavaScript	javascript	✅ ESLint	-
Python	python	✅ ast.parse()	-
Ruby	ruby	✅ ruby -c	-
PHP	php	✅ php -l	-
Go	go	✅ go build	✅
.NET	csharp	✅ dotnet build	✅
Java	java	-	-
Android	kotlin	-	-
Cocoa	swift	-	-
React Native	javascript	✅ ESLint	-
Rust	rust	✅ cargo check	✅
Elixir	elixir	-	-

Example Templates

The playground includes 50+ pre-built examples organized by mode:

Before Send Examples

• PII Scrubbing (JavaScript, Python, .NET, Ruby, Rust)
• Conditional Event Dropping (JavaScript, PHP, Go, Rust)
• Service Metadata Enrichment (Go, Rust)
• Custom Tags & Context (JavaScript, Java, Cocoa)
• Unity Metadata Cleanup (Android)

Fingerprinting Examples

• Custom Fingerprinting (JavaScript)
• Normalize Database Errors (JavaScript)
• Normalize API URL Errors (JavaScript)
• Split by User Type (JavaScript)

Before Send Transaction Examples

• Drop Health Checks (JavaScript, Python, Go)
• Add Custom Tags (JavaScript)
• Filter Slow Spans (JavaScript)
• Scrub Sensitive URLs (JavaScript)

Before Breadcrumb Examples

• Filter Console Breadcrumbs (JavaScript)
• Scrub PII from URLs (JavaScript, Python)
• Drop HTTP Noise (JavaScript)
• Categorize Breadcrumbs (JavaScript)

Traces Sampler Examples

• Critical Endpoints Sampling (JavaScript)
• Health Check Filtering (JavaScript)
• User-Based Sampling (JavaScript)
• Environment-Based Sampling (Python)

See Examples Library for the complete catalog.

Sharing Configurations

Share your configurations securely with colleagues or customers:

1. Configure your event/code in any mode
2. Click the Share button
3. Copy the generated URL (expires after 30 days)

Security: Event values are automatically scrubbed before sharing. Only the structure (field names and types) is preserved, along with your code.

Documentation

Getting Started

• Examples Library - Complete catalog of 50+ templates
• Choosing a Mode - Decision guide for mode selection
• SDK Support - Available SDKs and versions

Mode Guides

• Before Send Guide - Error event transformation
• Fingerprinting Guide - Custom issue grouping
• Before Send Transaction Guide - Transaction filtering
• Before Breadcrumb Guide - Breadcrumb filtering
• Traces Sampler Guide - Dynamic sampling strategies
• Pattern Tester Guide - Filter pattern testing
• Config Analyzer Guide - Configuration analysis
• API Query Tester Guide - Query testing
• Webhooks Guide - Webhook testing

Architecture

• Architecture Overview - System design and structure
• Architecture Deep Dive - Detailed technical docs with visual diagrams
  • System Architecture Diagram - 3-tier Docker microservices layout
  • Request Flow Diagram - Sequence diagrams for transform, config analysis, and query validation
  • Health Score Algorithm - Flowchart of the scoring and recommendation engine

Reference

• API Reference - API endpoints and usage
• Development Guide - Contributing, testing, TDD workflow
• Troubleshooting - Common issues and solutions

Requirements

• Docker & Docker Compose (required)
• That's it! Everything runs in Docker.

Stop Services

docker-compose down

Support

This tool is maintained by Sentry's Solutions Engineering team for customer support and internal testing.

For questions or issues, reach out to the SE team or file an issue in the repository.

License

MIT