AI optimization issue

AI node in loop without batching in n8n

Why processing items one by one through AI nodes wastes money and time

What is this issue?

When an AI node is inside a loop (SplitInBatches with batch size 1), each item makes a separate API call. This multiplies API overhead, increases latency, and can quickly exhaust rate limits and budgets.

Inefficient patterns:

  • SplitInBatches(1) → OpenAI node processing one item at a time
  • Loop Over Items with AI call inside
  • 100 items = 100 separate API calls instead of batched request
  • Sequential AI processing when parallel is possible

Why is this dangerous?

Excessive API calls

Each item triggers a separate API call with its own overhead and latency.

Rate limit exhaustion

AI providers rate-limit by requests per minute. Single-item loops hit limits fast.

Higher costs

Some AI providers have per-request minimums. Batching reduces effective cost per item.

Slow execution

Sequential calls take N × (latency) instead of log(N) × (latency) with proper batching.

How to fix it

  1. 1

    Increase batch size

    If using SplitInBatches, increase batch size to process multiple items per AI call.

  2. 2

    Combine inputs into single prompt

    Format multiple items as a single prompt and parse the structured response.

  3. 3

    Use parallel processing

    When items are independent, use n8n's parallel execution to run multiple AI calls simultaneously.

  4. 4

    Use batch endpoints

    Some AI providers offer batch/bulk endpoints—use them when available.

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