# Constructive Realtime

> Subscriptions, notifications, change_log, CursorTracker, ephemeral realtime — real-time data via GraphQL subscriptions, PostGraphile live queries, change tracking, and ephemeral pg_notify delivery. Use when asked to 'add subscriptions', 'real-time updates', 'live queries', 'notifications', 'change_log', 'CursorTracker', 'websocket', 'ephemeral realtime', 'pg_notify', 'high-frequency signals', or when working with real-time features in Constructive.

- Skill: `constructive-io/constructive-realtime` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add constructive-io/constructive-realtime`
- Raw SKILL.md: https://api.skillmd.com/api/skills/constructive-io/constructive-realtime/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: constructive-io (https://skillmd.com/u/constructive-io)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/constructive-io/constructive-realtime

---


# Constructive Realtime

Real-time data delivery via GraphQL subscriptions, live queries, and change tracking.

## When to Apply

Use this skill when:
- Adding real-time subscriptions to a Constructive app
- Working with PostGraphile live queries
- Implementing change tracking and notifications
- Using WebSocket connections for real-time updates
- Using ephemeral realtime for high-frequency signals (cursors, presence, live indicators)

## Core Concepts

### GraphQL Subscriptions

PostGraphile v5 provides built-in subscription support via WebSocket (graphql-ws protocol). Subscriptions are automatically generated for any table with appropriate grants.

### Live Queries

PostGraphile's `@stream` and `@live` directives enable:
- **Live queries** — auto-refresh results when underlying data changes
- **Streaming** — progressive delivery of large result sets

### Change Tracking

The `change_log` system records row-level changes (INSERT, UPDATE, DELETE) that power both subscriptions and audit trails.

### Ephemeral Realtime

`DataRealtime({ ephemeral: true })` bypasses `change_log` entirely — events go straight from trigger → `pg_notify` → WebSocket with zero write overhead. Designed for high-frequency signals (cursor positions, presence indicators, live typing) where durability isn't needed.

## References

| File | Content |
|------|---------|
| [realtime-subscriptions.md](./references/realtime-subscriptions.md) | Full subscription setup, WebSocket config, ephemeral mode, and patterns |

## Cross-References

- **Server configuration:** [`constructive-platform`](../constructive-platform/SKILL.md)
- **Generated hooks (React Query):** [`constructive-hooks`](../constructive-hooks/SKILL.md)
- **Events and tracking:** [`constructive-events`](../constructive-events/SKILL.md)