Automated PDF Invoice Processing & Approval Flow using OpenAI and Google Sheets

n8n template #4452

Summary

Who is this for? This workflow is ideal for: Finance teams that need to process incoming invoices faster with minimal errors Small to mid-sized businesses that want to automate invoice intake, review, and storage Operations managers who require approval workflows and centralized record-keeping What problem is this workflow solving? Manually processing invoices is time-consuming, error-prone, and often lacks structure. This workflow solves those challenges by: Automating the intake of invoices from multiple sources (email, Google Drive, web form) Extracting invoice data using AI, eliminating manual data entry Implementing an email-based approval system to add human oversight Automatically sto

How to set it up

Open template #4452 on n8n.io and click Use for free, or copy the template JSON and paste it onto an empty canvas in n8n.
Create 4 credentials under Credentials → Add credential: Google Sheets, Google Drive, Gmail, OpenAI Chat Model. Then open each of those nodes and pick the credential.
Check the model in the AI Agent node. The template may point at a model your account can't use; swap it for one you have access to.
Click Execute workflow and step through each node's output to confirm the data looks right.
Toggle the workflow to Active so its trigger runs on its own.

Hand off to your agent

Prompt

Help me set up the n8n workflow "Automated PDF Invoice Processing & Approval Flow using OpenAI and Google Sheets" (https://n8n.io/workflows/4452). It uses: Google Sheets, Google Drive, Gmail, AI Agent, OpenAI Chat Model, Structured Output Parser. Import the template JSON into my n8n instance, list every credential I need to create, and walk me through testing it.

Paste into Claude Code and it will do the rest.

Apps and nodes

Google Sheets Google Drive Gmail AI Agent OpenAI Chat Model Structured Output Parser

Questions

Yes. Billy Christi published it free on n8n.io as a verified creator, and it has 9,817 views. It runs on n8n Cloud or a self-hosted n8n instance.

Google Sheets, Google Drive, Gmail, OpenAI Chat Model. The other 2 nodes are built into n8n.

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