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event-store-design

Design and implement event stores for event-sourced systems. Use when building event sourcing infrastructure, choosing event store technologies, or implementing event persistence patterns.

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wshobson/agents
Updated
2026-05-29
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wshobson--agents--event-store-design
View on GitHubRaw SKILL.md

// install — copy + paste into any project

mkdir -p .claude/skills && curl -fsSL https://raw.githubusercontent.com/wshobson/agents/HEAD/plugins/backend-development/skills/event-store-design/SKILL.md -o .claude/skills/event-store-design.md

Drops the SKILL.md into .claude/skills/event-store-design.md. Works with Claude Code, Cursor, and any agent that loads SKILL.md files from .claude/skills/.

Event Store Design

Comprehensive guide to designing event stores for event-sourced applications.

When to Use This Skill

  • Designing event sourcing infrastructure
  • Choosing between event store technologies
  • Implementing custom event stores
  • Optimizing event storage and retrieval
  • Setting up event store schemas
  • Planning for event store scaling

Core Concepts

1. Event Store Architecture

┌─────────────────────────────────────────────────────┐
│                    Event Store                       │
├─────────────────────────────────────────────────────┤
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐ │
│  │   Stream 1   │  │   Stream 2   │  │   Stream 3   │ │
│  │ (Aggregate)  │  │ (Aggregate)  │  │ (Aggregate)  │ │
│  ├─────────────┤  ├─────────────┤  ├─────────────┤ │
│  │ Event 1     │  │ Event 1     │  │ Event 1     │ │
│  │ Event 2     │  │ Event 2     │  │ Event 2     │ │
│  │ Event 3     │  │ ...         │  │ Event 3     │ │
│  │ ...         │  │             │  │ Event 4     │ │
│  └─────────────┘  └─────────────┘  └─────────────┘ │
├─────────────────────────────────────────────────────┤
│  Global Position: 1 → 2 → 3 → 4 → 5 → 6 → ...     │
└─────────────────────────────────────────────────────┘

2. Event Store Requirements

Requirement Description
Append-only Events are immutable, only appends
Ordered Per-stream and global ordering
Versioned Optimistic concurrency control
Subscriptions Real-time event notifications
Idempotent Handle duplicate writes safely

Technology Comparison

Technology Best For Limitations
EventStoreDB Pure event sourcing Single-purpose
PostgreSQL Existing Postgres stack Manual implementation
Kafka High-throughput streaming Not ideal for per-stream queries
DynamoDB Serverless, AWS-native Query limitations
Marten .NET ecosystems .NET specific

Templates and detailed worked examples

Full template library and detailed worked examples live in references/details.md. Read that file when you need the concrete templates.

Best Practices

Do's

  • Use stream IDs that include aggregate type - Order-{uuid}
  • Include correlation/causation IDs - For tracing
  • Version events from day one - Plan for schema evolution
  • Implement idempotency - Use event IDs for deduplication
  • Index appropriately - For your query patterns

Don'ts

  • Don't update or delete events - They're immutable facts
  • Don't store large payloads - Keep events small
  • Don't skip optimistic concurrency - Prevents data corruption
  • Don't ignore backpressure - Handle slow consumers