Categorize Airtable invoices with OpenAI and TOON token optimization — n8n Workflow

Medium complexity⚡ Trigger12 nodes🏷️ Invoice Processing👁 1 viewsby CustomJS

Overview

> ⚠️ Notice:
> This workflow uses the CustomJS JSON to TOON node from CustomJS, which requires a self-hosted n8n instance and a CustomJS API key.

This workflow demonstrates how to automatically categorize invoices from Airtable using OpenAI, while significantly reducing token usage by converting structured data into TOON (Token-Optimized Object Notation) before sending it to the LLM.

Instead of passing large, nested JSON payloads (clients, invoices, invoice items) directly to OpenAI,

Nodes used

AirtableOpenAI

Workflow Preview

Categorizing invoices with TOON optimization
Here is an example of how you can categorize all
your invoices in Airtable, from our [invoice creation e
Collect invoice data from Airtable
Categorizing Invoices
Save categories back to Airtable
OpenAI Enhancement
J
JSON to TOON
⚡
W
When clicking ‘Execute w…
Get Ready Invoices
Get Clients
Get Invoice Items
A
Aggregate
L
Loop Over Items
Update record
M
Map Fields
G
GroupClientAndInvoice
T
TOON to JSON
12 nodes12 edges

How it Works

  1. 1

    Trigger

    The workflow starts with a trigger trigger.

  2. 2

    Process

    Data flows through 12 nodes, connecting @custom-js/n8n-nodes-pdf-toolkit.jsontotoon, @custom-js/n8n-nodes-pdf-toolkit.toontojson, aggregate.

  3. 3

    Output

    The workflow completes its automation and delivers the result to the configured destination.

Node Details (12)

AI

Airtable

airtable

#1
OP

OpenAI

n8n-nodes-langchain.openAi

#2

How to Import This Workflow

  1. 1Click Download JSON button on the right to save the workflow file.
  2. 2Open your n8n instance. Go to Workflows → New → Import from file.
  3. 3Select the downloaded categorize-airtable-invoices-with-openai-and-toon-token-optimization file and click Import.
  4. 4Set up credentials for each service node (API keys, OAuth, etc.).
  5. 5Click Test Workflow to verify everything works, then activate it.

Or paste directly in n8n → Import from JSON:

{ "name": "Categorize Airtable invoices with OpenAI and TOON token optimization", "nodes": [...], ...}

Integrations

@custom-js/n8n-nodes-pdf-toolkit.jsontotoon@custom-js/n8n-nodes-pdf-toolkit.toontojsonaggregateairtablemanualtriggeropenaisetsplitinbatches

Get This Workflow

Download and import in one click

Download JSONView on n8n.io
Nodes12
Complexitymedium
Triggertrigger
Views1
CategoryInvoice Processing

Created by

CustomJS

CustomJS

@customjs

Tags

@custom-js/n8n-nodes-pdf-toolkit.jsontotoon@custom-js/n8n-nodes-pdf-toolkit.toontojsonaggregateairtablemanualtriggeropenaisetsplitinbatches
⚡

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🔗 Webhook·12 nodes