# walkerOS Documentation

> Privacy-first, composable event data collection (Source → Collector → Destination).


## docs

Event data collection as code - capture, transform, and route events with built-in consent management

- [What is walkerOS](/docs.md): Event data collection as code - capture, transform, and route events with built-in consent management

### getting-started

- [Deploy](/docs/getting-started/deploy.md): Take your flow to production, self-hosted or managed
- [Event model](/docs/getting-started/event-model.md): Understanding the walkerOS event data structure
- [Bot detection](/docs/getting-started/examples/bot-detection.md): Annotate every server event with a bot and AI-agent score
- [Fingerprint to BigQuery](/docs/getting-started/examples/fingerprint-bigquery.md): Hash IP and user agent into a privacy-friendly id, then land events in BigQuery
- [One event, four tools](/docs/getting-started/examples/mapping-comparison.md): Fan a single event stream out to GA4, Amplitude, Mixpanel, and PostHog
- [First critical checks](/docs/getting-started/first-checks.md): Evaluate walkerOS in 15 minutes, five proofs on your own machine
- [Flow](/docs/getting-started/flow.md): Understanding the walkerOS flow configuration file structure
- [Contract](/docs/getting-started/flow/contract.md): Named, inheritable event schemas that define what your data should look like
- [Step examples](/docs/getting-started/flow/step-examples.md): Embed input/output examples on each flow step for testing, documentation, and simulation
- [Validate](/docs/getting-started/flow/validate.md): Enforce a contract at runtime with the validate transformer.
- [GA4 ecommerce](/docs/getting-started/ga4-ecommerce.md): Send a page view and a product add event to Google Analytics 4
- [Operating modes](/docs/getting-started/modes.md): Two ways to use walkerOS - integrated and bundled
- [Bundled mode](/docs/getting-started/modes/bundled.md): Configure walkerOS with JSON and build standalone bundles with the CLI
- [Integrated mode](/docs/getting-started/modes/integrated.md): Build walkerOS directly into your application with full TypeScript control
- [Quickstart](/docs/getting-started/quickstart.md): Send your first walkerOS event in five minutes
- [Docker](/docs/getting-started/quickstart/docker.md): Get walkerOS running with Docker in 5 minutes
- [Next.js Quickstart](/docs/getting-started/quickstart/nextjs.md): Get started with walkerOS in Next.js applications
- [React Quickstart](/docs/getting-started/quickstart/react.md): Get started with walkerOS in React applications
- [Stores](/docs/getting-started/stores.md): Key-value storage for walkerOS components

### sources

Event data sources for walkerOS collector

- [Sources](/docs/sources.md): Event data sources for walkerOS collector
- [Create Your Own Source](/docs/sources/create-your-own.md): Guide to building custom sources for walkerOS
- [Server sources](/docs/sources/server.md): HTTP event collection sources for server environments
- [AWS Lambda](/docs/sources/server/aws.md): AWS Lambda HTTP handler for event collection
- [Express](/docs/sources/server/express.md): Turn-key HTTP event collection server with Express.js
- [Fetch](/docs/sources/server/fetch.md): Web Standard Fetch API source for edge and serverless platforms
- [GCP Cloud Functions](/docs/sources/server/gcp.md): Google Cloud Functions HTTP handler source for walkerOS
- [Google Pub/Sub](/docs/sources/server/pubsub.md): Server-side ingestion from Google Cloud Pub/Sub via streaming pull subscriber or HTTP push webhook
- [AWS SQS](/docs/sources/server/sqs.md): Server-side ingestion from Amazon SQS via streaming long-poll subscriber
- [Browser source](/docs/sources/web/browser.md): DOM-based event tracking for web applications
- [Browser source commands](/docs/sources/web/browser/commands.md): Browser source API methods and commands
- [Tagger](/docs/sources/web/browser/tagger.md): HTML data attribute generator for walkerOS event tracking
- [HTML Attributes](/docs/sources/web/browser/tagging/html-attributes.md): How to tag a page using data-elb HTML attributes
- [JavaScript](/docs/sources/web/browser/tagging/javascript.md): Capture events programmatically using the elb function
- [CMP sources](/docs/sources/web/cmps.md): Automate consent handling with walkerOS CMP source packages
- [CookieFirst](/docs/sources/web/cmps/cookiefirst.md): Integrate CookieFirst consent management with walkerOS
- [CookiePro / OneTrust](/docs/sources/web/cmps/cookiepro.md): Integrate CookiePro/OneTrust consent management with walkerOS
- [Usercentrics](/docs/sources/web/cmps/usercentrics.md): Integrate Usercentrics consent management with walkerOS
- [DataLayer source](/docs/sources/web/dataLayer.md): Integration with existing dataLayer implementations
- [Session source](/docs/sources/web/session.md): Standalone session detection and management for walkerOS

### collector

Unified event collector for web and server environments

- [Collector](/docs/collector.md): Unified event collector for web and server environments
- [Cache](/docs/collector/cache.md): Cache is a built-in config property available on every step type (source, transformer, destination). It prevents redundant processing by caching results and serving them on subsequent matching requests.
- [Collector commands](/docs/collector/commands.md): Collector API methods and commands
- [Logger](/docs/collector/logger.md): Centralized logging system for walkerOS
- [State](/docs/collector/state.md): State is a built-in config property available on source, transformer, and destination steps. It replaces inline $code stash a value (set) and fetch a value (get). Both directions reuse the same mapping engine, so any value you can express in a mapping you can stash or fetch.

### destinations

Send events to analytics tools, marketing platforms, and custom endpoints

- [Destinations](/docs/destinations.md): Send events to analytics tools, marketing platforms, and custom endpoints
- [API Destination](/docs/destinations/api.md): Send events to any HTTP endpoint - browser or server-side
- [Server API Destination](/docs/destinations/api/server.md): Server-side HTTP API destination for Node.js
- [Web API Destination](/docs/destinations/api/web.md): Browser-side HTTP API destination with fetch, XHR, and beacon transports
- [Code Destination](/docs/destinations/code.md): Built-in destination for executing custom code strings
- [Create Your Own Destination](/docs/destinations/create-your-own.md): A guide to building custom destinations for walkerOS.
- [Amplitude](/docs/destinations/server/amplitude.md): Server-side event delivery to Amplitude for product analytics with per-event identity
- [AWS Firehose](/docs/destinations/server/aws.md): Stream events to Amazon Kinesis Data Firehose for real-time analytics
- [Bing UET Conversions API](/docs/destinations/server/bing.md): Server-side event delivery to Microsoft Advertising (Bing) UET Conversions API for enhanced conversion tracking
- [Criteo Events API](/docs/destinations/server/criteo.md): Server-side event delivery to Criteo's Events API for retargeting
- [Customer.io](/docs/destinations/server/customerio.md): Server-side event delivery to Customer.io for email, SMS, push, and in-app messaging automation
- [Google Data Manager API](/docs/destinations/server/datamanager.md): Server-side event ingestion via the Google Data Manager API to Google Ads, Display & Video 360, and Google Analytics 4
- [File](/docs/destinations/server/file.md): Local file sink for walkerOS server flows. Appends events as JSONL, TSV, or CSV for debug logging, audit trails, and cold archive.
- [Google BigQuery](/docs/destinations/server/gcp.md): Stream events to Google BigQuery via the Storage Write API for analytics and machine learning workloads
- [HubSpot](/docs/destinations/server/hubspot.md): Server-side event delivery to HubSpot CRM (custom events + contact upsert)
- [Apache Kafka](/docs/destinations/server/kafka.md): Server-side event streaming to Apache Kafka topics via kafkajs with JSON serialization and compression
- [Klaviyo](/docs/destinations/server/klaviyo.md): Server-side event delivery to Klaviyo for email and SMS marketing automation
- [LinkedIn Conversions API](/docs/destinations/server/linkedin.md): Server-side conversion event delivery to LinkedIn for enhanced ad attribution
- [Meta Conversions API](/docs/destinations/server/meta-capi.md): Server-side Meta advertising events for enhanced privacy and tracking accuracy
- [Mixpanel](/docs/destinations/server/mixpanel.md): Server-side event delivery to Mixpanel for product analytics with people profiles and groups
- [mParticle](/docs/destinations/server/mparticle.md): Server-side event delivery to mParticle CDP via input feed batches
- [Pinterest Conversions API](/docs/destinations/server/pinterest.md): Server-side event delivery to Pinterest Conversions API for enhanced conversion tracking
- [PostHog](/docs/destinations/server/posthog.md): Server-side event delivery to PostHog for product analytics and feature flags
- [Google Pub/Sub](/docs/destinations/server/pubsub.md): Server-side event publishing to Google Cloud Pub/Sub topics with per-key ordering and dynamic attributes
- [Reddit Conversions API](/docs/destinations/server/reddit.md): Server-side event delivery to Reddit Conversions API for enhanced conversion tracking
- [Redis Streams](/docs/destinations/server/redis.md): Server-side event streaming to Redis Streams via ioredis with XADD, MAXLEN trimming, and JSON or flat serialization
- [RudderStack](/docs/destinations/server/rudderstack.md): Server-side event delivery to RudderStack CDP (open-source Segment alternative) with full Segment Spec support
- [Segment](/docs/destinations/server/segment.md): Server-side event delivery to Segment CDP for routing to 400+ downstream destinations
- [Slack](/docs/destinations/server/slack.md): Server-side Slack notifications with dual-mode support (Incoming Webhooks + Web API)
- [Snapchat Conversions API](/docs/destinations/server/snapchat.md): Server-side event delivery to Snapchat Conversions API for enhanced conversion tracking
- [AWS SNS](/docs/destinations/server/sns.md): Server-side event publishing to AWS SNS topics with FIFO ordering, KMS encryption, and idempotent topic provisioning
- [SQLite](/docs/destinations/server/sqlite.md): Server-side event persistence to a local SQLite file (better-sqlite3) or remote libSQL / Turso (@libsql/client). Driver picked automatically from the URL.
- [TikTok Events API](/docs/destinations/server/tiktok.md): Server-side event delivery to TikTok Events API for enhanced conversion tracking
- [X (Twitter) Conversions API](/docs/destinations/server/twitter.md): Server-side conversion event delivery to X (Twitter) for enhanced ad attribution
- [Amplitude](/docs/destinations/web/amplitude.md): Product analytics, identity, revenue, and optional session replay, experiments, and guides & surveys
- [Microsoft Clarity](/docs/destinations/web/clarity.md): Session replays, heatmaps, and behavioural insights
- [d8a](/docs/destinations/web/d8a.md): GA4-compatible, warehouse-native analytics
- [FullStory](/docs/destinations/web/fullstory.md): Session replay, custom events, and user/page properties
- [Google Gtag](/docs/destinations/web/gtag.md): Unified Google destination supporting GA4, Google Ads, and GTM through a single gtag implementation
- [Google Ads](/docs/destinations/web/gtag/ads.md): Google Ads conversion tracking within the unified gtag destination
- [Google Analytics 4 (GA4)](/docs/destinations/web/gtag/ga4.md): Google Analytics 4 configuration within the unified gtag destination
- [Google Tag Manager (GTM)](/docs/destinations/web/gtag/gtm.md): Google Tag Manager configuration within the unified gtag destination
- [Heap](/docs/destinations/web/heap.md): Product analytics with auto-capture and retroactive events
- [Hotjar](/docs/destinations/web/hotjar.md): Session recordings, heatmaps, and on-page feedback
- [LinkedIn Insight Tag](/docs/destinations/web/linkedin.md): Conversion tracking and retargeting for LinkedIn Campaign Manager
- [Matomo](/docs/destinations/web/matomo.md): Self-hosted or cloud privacy-first web analytics (GA alternative)
- [Meta Pixel](/docs/destinations/web/meta-pixel.md): Facebook and Instagram advertising pixel integration
- [Mixpanel](/docs/destinations/web/mixpanel.md): Product analytics with people profiles and group analytics
- [Optimizely](/docs/destinations/web/optimizely.md): Feature experimentation, A/B testing, and conversion tracking
- [Piano Analytics](/docs/destinations/web/piano.md): Send events to Piano Analytics
- [Pinterest Tag](/docs/destinations/web/pinterest.md): Conversion tracking, enhanced matching, and dynamic retargeting via the Pinterest Tag
- [Piwik PRO](/docs/destinations/web/piwikpro.md): Privacy-focused web analytics and visitor data platform
- [Plausible Analytics](/docs/destinations/web/plausible.md): Simple, privacy-friendly and lightweight analytics
- [PostHog](/docs/destinations/web/posthog.md): Product analytics, session replay, feature flags, surveys
- [Segment](/docs/destinations/web/segment.md): Segment CDP, routing events to 400+ downstream destinations
- [Snowplow](/docs/destinations/web/snowplow.md): Behavioral data platform destination with ecommerce tracking
- [TikTok Pixel](/docs/destinations/web/tiktok.md): Conversion tracking and Advanced Matching for TikTok Ads

### transformers

Event processing middleware for walkerOS collector

- [Transformers](/docs/transformers.md): Event processing middleware for walkerOS collector
- [Bot detection](/docs/transformers/bot.md): Server-side bot and AI-agent annotation
- [Create your own transformer](/docs/transformers/create-your-own.md): Guide to building custom transformers for walkerOS
- [File](/docs/transformers/file.md): Serve static files from a store backend with MIME detection
- [Fingerprint](/docs/transformers/fingerprint.md): Server-side user identification via deterministic hashing
- [GA4](/docs/transformers/ga4.md): Decode Google Analytics 4 Measurement Protocol v2 hits into walkerOS events
- [Validate](/docs/transformers/validate.md): Enforce JSON Schema contracts on events at runtime

### stores

Key-value storage for walkerOS flows

- [Stores](/docs/stores.md): Key-value storage for walkerOS flows
- [Store-level cache](/docs/stores/cache.md): Cache reads and writes on any walkerOS store with the built-in tier, compose multi-tier chains, deduplicate concurrent reads.
- [Filesystem](/docs/stores/server/fs.md): Local filesystem store for walkerOS server flows
- [GCS](/docs/stores/server/gcs.md): Google Cloud Storage for walkerOS server flows
- [S3](/docs/stores/server/s3.md): S3-compatible object storage for walkerOS server flows
- [Sheets](/docs/stores/server/sheets.md): Google Sheets store for walkerOS server flows

### mapping

Transform events with a code-free, declarative mapping syntax

- [Mapping](/docs/mapping.md): Transform events with a code-free, declarative mapping syntax
- [Mapping.Rule](/docs/mapping/rule.md): How a destination rule composes values into a complete transform
- [Mapping.Value](/docs/mapping/value.md): The polymorphic primitive you put into any mapping field

### apps

Ready-to-use walkerOS bundle for instant web tracking

- [Apps](/docs/apps.md): Ready-to-use walkerOS bundle for instant web tracking
- [walkerOS CLI](/docs/apps/cli.md): walkerOS command-line tool for building, testing, and running flows
- [walkerOS Docker](/docs/apps/docker.md): Deploy walkerOS flows with Docker containers
- [MCP servers](/docs/apps/mcp.md): Use walkerOS tools from AI assistants via Model Context Protocol
- [walkerOS Runner](/docs/apps/runner.md): Self-hosted walkerOS runner with config polling, hot-swap, and dashboard visibility
- [Storybook addon](/docs/apps/storybook.md): Visualize and debug walkerOS events in Storybook
- [Telemetry](/docs/apps/telemetry.md): What walkerOS CLI and MCP can collect, how to opt in, and what "opt in" means legally.
- [walker.js](/docs/apps/walkerjs.md): Ready-to-use walkerOS bundle for instant web tracking

### guides

How-to guides and best practices for walkerOS

- [Guides](/docs/guides.md): How-to guides and best practices for walkerOS
- [Consent management](/docs/guides/consent.md): Privacy-compliant consent handling and management with walkerOS
- [My events aren't arriving](/docs/guides/debugging.md): A how-to for tracing walkerOS events when a destination stays silent
- [Deploy walkerOS to Bunny Magic Containers](/docs/guides/deploy-bunny-magic-containers.md): Deploy walkerOS to Bunny Magic Containers with BigQuery destination
- [Deploy walkerOS to GCP Cloud Run](/docs/guides/deploy-gcp-cloudrun.md): Deploy walkerOS to Google Cloud Run with BigQuery destination
- [Migration guide: from @elbwalker to @walkerOS](/docs/guides/migration.md): How to migrate to the latest walkerOS packages
- [Reference Syntax](/docs/guides/reference-syntax.md): Dynamic references inside flow.json, variables, env vars, contracts, stores, secrets, inline code.
- [Session](/docs/guides/session.md): Detect and track user sessions with configurable storage and consent options
- [User stitching](/docs/guides/user-stitching.md): User identification and cross-device/cross-session data unification with walkerOS

### comparisons

Comparisons between walkerOS and other popular tracking and analytics solutions

- [Comparisons](/docs/comparisons.md): Comparisons between walkerOS and other popular tracking and analytics solutions
- [walkerOS tagging vs. dataLayer.push](/docs/comparisons/dataLayer.md): Compare walkerOS HTML tagging with manual dataLayer.push calls.
- [walkerOS vs. Google Tag Manager](/docs/comparisons/gtm.md): Compare walkerOS and Google Tag Manager to understand which solution fits your needs.
- [walkerOS vs. Jentis](/docs/comparisons/jentis.md): Compare walkerOS and Jentis to understand which solution fits your needs.
- [walkerOS vs. Jitsu](/docs/comparisons/jitsu.md): Compare walkerOS and Jitsu to understand which solution fits your needs.
- [walkerOS vs. RudderStack](/docs/comparisons/rudderstack.md): Compare walkerOS and RudderStack to understand which solution fits your needs.
- [walkerOS vs. Segment](/docs/comparisons/segment.md): Compare walkerOS and Twilio Segment to understand which solution fits your needs.
- [walkerOS vs. Snowplow](/docs/comparisons/snowplow.md): Compare walkerOS and Snowplow to understand which solution fits your needs.
- [walkerOS vs. Stape](/docs/comparisons/stape.md): Compare walkerOS and Stape to understand which solution fits your needs.

### contributing

Learn how to contribute to walkerOS

- [Contributing](/docs/contributing.md): Learn how to contribute to walkerOS

### core

Core libraries and utilities for walkerOS

- [Core utilities](/docs/core.md): Core libraries and utilities for walkerOS
- [Server Core Utilities](/docs/core/server.md): Server-specific utilities and extensions for walkerOS
- [Web Core Utilities](/docs/core/web.md): Web-specific utilities and extensions for walkerOS

### migrate

- [Migrating to @walkeros/cli 4.x](/docs/migrate/cli-4x.md): nft-traced bundler, output filename, Dockerfile updates

### migrating

- [Migrating flow.json from v3 to v4](/docs/migrating/v3-to-v4.md): Upgrade existing flow.json files to the v4 schema introduced in walkerOS Flow v4.

### plans

- [FlowMap Diagrams Implementation Plan](/docs/plans/2026-01-14-flowmap-diagrams.md): For Claude Use superpowers:executing-plans to

### upgrading

How walkerOS clients negotiate versions with the app, and what to do when you see a 426 Upgrade Required response.

- [Upgrading walkerOS clients](/docs/upgrading.md): How walkerOS clients negotiate versions with the app, and what to do when you see a 426 Upgrade Required response.

## skills

Index of walkerOS skills, the source of truth for AI assistants and developers.

- [walkerOS Skills](/skills.md): Index of walkerOS skills, the source of truth for AI assistants and developers.

### walkeros-create-cmp-source

Use when creating a new walkerOS CMP (consent management platform) source. Structured fill-in-the-blanks workflow that turns any CMP's consent API into a walkerOS source package. Covers CookieFirst, Usercentrics, CookiePro/OneTrust patterns and generalizes to any CMP.

- [Create a CMP Source](/skills/walkeros-create-cmp-source.md): Use when creating a new walkerOS CMP (consent management platform) source. Structured fill-in-the-blanks workflow that turns any CMP's consent API into a walkerOS source package. Covers CookieFirst, Usercentrics, CookiePro/OneTrust patterns and generalizes to any CMP.

### walkeros-create-destination

Use when creating a new walkerOS destination to send events to a vendor or API (GA4/gtag, Meta/Facebook Pixel, Mixpanel, Amplitude, a custom HTTP API, Measurement Protocol), web or server-side. Example-driven workflow: research the vendor SDK and define step examples before implementing the destination interface, env pattern, and mappings.

- [Create a New Destination](/skills/walkeros-create-destination.md): Use when creating a new walkerOS destination to send events to a vendor or API (GA4/gtag, Meta/Facebook Pixel, Mixpanel, Amplitude, a custom HTTP API, Measurement Protocol), web or server-side. Example-driven workflow: research the vendor SDK and define step examples before implementing the destination interface, env pattern, and mappings.

### walkeros-create-source

Use when creating a new walkerOS source to capture events (browser source, dataLayer interception, server/HTTP source, webhook receiver, event capture), web or server-side. Example-driven workflow: research the input format and define step examples before implementing the push interface, createTrigger, and env pattern.

- [Create a New Source](/skills/walkeros-create-source.md): Use when creating a new walkerOS source to capture events (browser source, dataLayer interception, server/HTTP source, webhook receiver, event capture), web or server-side. Example-driven workflow: research the input format and define step examples before implementing the push interface, createTrigger, and env pattern.

### walkeros-create-transformer

Use when creating a new walkerOS transformer to modify events in the pipeline (validate, enrich, or redact) at a before/next chain position. Example-driven workflow for the transformer interface, return values, and chaining.

- [Create a New Transformer](/skills/walkeros-create-transformer.md): Use when creating a new walkerOS transformer to modify events in the pipeline (validate, enrich, or redact) at a before/next chain position. Example-driven workflow for the transformer interface, return values, and chaining.

### walkeros-debugging

Use when walkerOS events aren't reaching destinations, debugging event flow, or troubleshooting mapping issues. Covers common problems and debugging strategies.

- [Debugging walkerOS Events](/skills/walkeros-debugging.md): Use when walkerOS events aren't reaching destinations, debugging event flow, or troubleshooting mapping issues. Covers common problems and debugging strategies.

### walkeros-mapping-configuration

Use when configuring walkerOS event mappings for specific use cases. Provides recipes for GA4, Meta, custom APIs, and common transformation patterns.

- [Mapping Configuration Recipes](/skills/walkeros-mapping-configuration.md): Use when configuring walkerOS event mappings for specific use cases. Provides recipes for GA4, Meta, custom APIs, and common transformation patterns.

### walkeros-mcp-actions

Use when an AI agent calls walkerOS MCP tools from code (code execution / Code Mode, a Worker, or an app sandbox) to validate, simulate, bundle, or inspect flows and packages, and wants to filter large results in code instead of issuing many separate tool calls.

- [Calling walkerOS MCP Tools from Code](/skills/walkeros-mcp-actions.md): Use when an AI agent calls walkerOS MCP tools from code (code execution / Code Mode, a Worker, or an app sandbox) to validate, simulate, bundle, or inspect flows and packages, and wants to filter large results in code instead of issuing many separate tool calls.

### walkeros-testing-strategy

Use when writing tests, reviewing test code, or discussing testing approach for walkerOS packages. Covers env pattern, dev examples, and package-specific strategies.

- [walkerOS Testing Strategy](/skills/walkeros-testing-strategy.md): Use when writing tests, reviewing test code, or discussing testing approach for walkerOS packages. Covers env pattern, dev examples, and package-specific strategies.

### walkeros-understanding-destinations

Use when working with walkerOS destinations, understanding the destination interface, or learning about env pattern and configuration. Covers interface, lifecycle, env mocking, and paths.

- [Understanding walkerOS Destinations](/skills/walkeros-understanding-destinations.md): Use when working with walkerOS destinations, understanding the destination interface, or learning about env pattern and configuration. Covers interface, lifecycle, env mocking, and paths.

### walkeros-understanding-development

Use when contributing to walkerOS, before writing code, or when unsure about project conventions. Covers build/test/lint workflow, XP principles, folder structure, and package usage.

- [Understanding walkerOS Development](/skills/walkeros-understanding-development.md): Use when contributing to walkerOS, before writing code, or when unsure about project conventions. Covers build/test/lint workflow, XP principles, folder structure, and package usage.

### walkeros-understanding-events

Use when creating walkerOS events, understanding event structure, or working with event properties. Covers entity-action naming, event properties, statelessness, and vendor-agnostic design.

- [Understanding walkerOS Events](/skills/walkeros-understanding-events.md): Use when creating walkerOS events, understanding event structure, or working with event properties. Covers entity-action naming, event properties, statelessness, and vendor-agnostic design.

### walkeros-understanding-flow

Use when learning walkerOS architecture, understanding data flow, or designing composable event pipelines. Covers Source→Collector→Destination pattern and separation of concerns.

- [Understanding walkerOS Flow](/skills/walkeros-understanding-flow.md): Use when learning walkerOS architecture, understanding data flow, or designing composable event pipelines. Covers Source→Collector→Destination pattern and separation of concerns.

### walkeros-understanding-mapping

Use when transforming walkerOS events in the flow (source→collector or collector→destination), configuring data/map/loop/set/condition/policy, or using $code: syntax in JSON configs.

- [Understanding walkerOS Mapping](/skills/walkeros-understanding-mapping.md): Use when transforming walkerOS events in the flow (source→collector or collector→destination), configuring data/map/loop/set/condition/policy, or using $code: syntax in JSON configs.

### walkeros-understanding-sources

Use when working with walkerOS sources, understanding event capture, or learning about the push interface. Covers browser, dataLayer, and server source patterns.

- [Understanding walkerOS Sources](/skills/walkeros-understanding-sources.md): Use when working with walkerOS sources, understanding event capture, or learning about the push interface. Covers browser, dataLayer, and server source patterns.

### walkeros-understanding-stores

Use when working with walkerOS stores, understanding key-value storage in flows, or learning about store injection via env. Covers interface, lifecycle, $store. wiring, and available store packages.

- [Understanding walkerOS Stores](/skills/walkeros-understanding-stores.md): Use when working with walkerOS stores, understanding key-value storage in flows, or learning about store injection via env. Covers interface, lifecycle, $store. wiring, and available store packages.

### walkeros-understanding-transformers

Use when working with walkerOS transformers, understanding event validation/enrichment/redaction, or learning about transformer chaining. Covers interface, return values, and pipeline integration.

- [Understanding walkerOS Transformers](/skills/walkeros-understanding-transformers.md): Use when working with walkerOS transformers, understanding event validation/enrichment/redaction, or learning about transformer chaining. Covers interface, return values, and pipeline integration.

### walkeros-using-cli

Use when bundling walkerOS flows, testing events with simulate/push, running local servers, validating configs, or configuring Flow JSON files.

- [Using the walkerOS CLI](/skills/walkeros-using-cli.md): Use when bundling walkerOS flows, testing events with simulate/push, running local servers, validating configs, or configuring Flow JSON files.

### walkeros-using-logger

Use when working with walkerOS sources/destinations to understand standard logging patterns, replace console.log, or add logging to external API calls. Covers DRY principles, when to log, and migration patterns.

- [Using the walkerOS Logger](/skills/walkeros-using-logger.md): Use when working with walkerOS sources/destinations to understand standard logging patterns, replace console.log, or add logging to external API calls. Covers DRY principles, when to log, and migration patterns.

### walkeros-using-step-examples

Use when writing, simulating, validating, or testing with walkerOS step examples. Covers the complete lifecycle from authoring examples to CI integration.

- [Using Step Examples](/skills/walkeros-using-step-examples.md): Use when writing, simulating, validating, or testing with walkerOS step examples. Covers the complete lifecycle from authoring examples to CI integration.

### walkeros-using-store-cache

Use when adding read-through caching to a walkerOS store, memoizing a slow API/Sheets backing, composing multi-tier cache chains, or deduplicating concurrent store reads. Covers recipes, TTL choice, error policy, and observability counters.

- [Using store-level cache](/skills/walkeros-using-store-cache.md): Use when adding read-through caching to a walkerOS store, memoizing a slow API/Sheets backing, composing multi-tier cache chains, or deduplicating concurrent store reads. Covers recipes, TTL choice, error policy, and observability counters.

### walkeros-using-transformer-ga4

Use when wiring `@walkeros/transformer-ga4` into a server flow, overriding default GA4 event mappings, dropping events, adding custom event keys, or troubleshooting GA4 Measurement Protocol decoding. Covers the `before`-chain wiring contract, configuration recipes, and per-field patching with extend/remove.

- [Using @walkeros/transformer-ga4](/skills/walkeros-using-transformer-ga4.md): Use when wiring `@walkeros/transformer-ga4` into a server flow, overriding default GA4 event mappings, dropping events, adding custom event keys, or troubleshooting GA4 Measurement Protocol decoding. Covers the `before`-chain wiring contract, configuration recipes, and per-field patching with extend/remove.

### walkeros-writing-documentation

Use when writing or updating walkerOS documentation - README, website docs, or skills. Covers quality standards, example validation, and DRY patterns.

- [Writing Documentation](/skills/walkeros-writing-documentation.md): Use when writing or updating walkerOS documentation - README, website docs, or skills. Covers quality standards, example validation, and DRY patterns.