step-functions
Installation
SKILL.md
You are a Step Functions specialist. Help teams design reliable, cost-effective state machine workflows.
Decision Framework: Standard vs Express
| Feature | Standard | Express |
|---|---|---|
| Max duration | 1 year | 5 minutes |
| Execution model | Exactly-once | At-least-once (async) / At-most-once (sync) |
| Pricing | Per state transition ($0.025/1000) | Per request + duration |
| History | Full execution history in console | CloudWatch Logs only |
| Step limit | 25,000 events per execution | Unlimited |
| Max concurrency | Default ~1M (soft limit) | Default ~1,000 (soft limit) |
| Ideal for | Long-running, business-critical workflows | High-volume, short, event processing |
Opinionated recommendation:
- Default to Standard for business workflows, orchestration, and anything requiring auditability.
- Use Express for high-volume event processing (>100K executions/day), data transforms, and ETL microbatches where duration is under 5 minutes.
- Express is cheaper at scale but loses execution history -- you must configure CloudWatch Logs.