# Batch vs Synchronous Processing

Choosing between interactive real-time requests and the Batch API's cheaper, high-latency asynchronous processing for large non-urgent jobs.

## Why the CCAR-P exam tests this

CCAR-P tests matching workload latency needs to the right execution mode and knowing the Batch API's cost and timing tradeoffs.

## Definition

**Synchronous** processing serves a request and returns the result immediately — the right choice for interactive, user-facing work where latency matters (chat, live agents).

The **Batch API** processes large volumes **asynchronously**: you submit many requests at once and collect results later. It runs at roughly **50% of standard token cost**, completes **within 24 hours** (often much sooner), and **supports tool use**. That makes it ideal for offline, non-time-sensitive jobs — bulk classification, evaluations, dataset generation, large-scale summarization.

The design decision is latency tolerance versus cost and throughput. If a user is waiting, go synchronous. If the work can wait and volume is high, batch it to halve cost and avoid rate-limit pressure. Many systems use both: synchronous for the interactive path, batch for the heavy offline backlog.

## Exam trap

Thinking the Batch API is only for simple prompts or can't use tools — it supports tool use, runs at ~50% cost, and completes within 24h; the real disqualifier is needing a low-latency interactive response.

## Commonly confused with

- **idempotency-and-retries** — Batch-vs-sync is an execution-mode choice; idempotency is a safety property of the individual operations either mode runs.

## Related

- workflow-vs-agent
- idempotency-and-retries
- model-selection
- cost-optimization
- prompt-caching

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Source: Claude Cert Prep — an independent, unofficial CCAR-P study resource (domain P1). Not affiliated with Anthropic.