phoenix-liveview_skill

Overview

This skill packages practical guidance for building fault-tolerant, real-time web apps with Phoenix and LiveView on the BEAM. It focuses on OTP supervision, context-driven domain design, LiveView patterns, PubSub/Presence, and production concerns like telemetry, releases, and scaling. The content is pragmatic and aimed at teams that want minimal client JS while keeping UI state on the server.

How this skill works

The skill inspects common Phoenix project structure and recommends patterns for application supervision, context APIs, Ecto changesets, and LiveView modules. It highlights where to place responsibilities (contexts vs LiveViews), how to use PubSub and Presence for realtime updates, and which BEAM/OTP primitives (GenServer, Supervisor, ETS) to prefer. It also covers testing, deployment commands, and operational telemetry for performance monitoring.

When to use it

• When building server-driven realtime UIs that minimize client-side JavaScript
• When you need resilient background processing and restartable components
• When designing domain boundaries and Ecto-based data APIs
• When you plan to scale across nodes and need clustered PubSub/Presence
• When preparing apps for production with releases, telemetry, and caching

Best practices

• Keep LiveViews thin: push business logic into contexts and use assign_new/3 for expensive work
• Supervise all stateful pieces with clear restart strategies and small isolated processes
• Use Ecto.Multi for multi-step DB operations to ensure atomicity and predictable rollbacks
• Subscribe to PubSub only after connected?/1 in LiveView to avoid missed events
• Measure LiveView diff sizes, use stream/3 for large lists, and prefer ETS/Cachex for hot caches

Example use cases

• A collaborative dashboard that broadcasts order events to many connected users using PubSub and Presence
• An authenticated user area where LiveView manages session-driven UIs and server-side state updates
• A background-job pipeline with Oban supervised in the application tree for retries and backoff
• A CRUD admin generated via mix phx.gen.live with domain logic encapsulated in contexts
• A clustered deployment using libcluster for distributed PubSub and presence across nodes