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Automation guide

How to Automate Invoice Processing with ChatGPT / GPT-4o (OpenAI)

Extract line items from PDF invoices, match against POs, flag discrepancies, and push to accounting automatically.

The problem

Finance teams manually key invoice data into accounting systems — a process that takes hours and introduces errors on 5-8% of invoices.

The outcome

Invoice cycle time drops from days to minutes. Discrepancies caught before payment. Zero manual data entry.

The tool

ChatGPT / GPT-4o (OpenAI) — OpenAI's GPT-4o is the most widely deployed LLM.

How it works — step by step

  1. 1

    Invoice arrives via email or upload portal

  2. 2

    AI extracts structured data (vendor, amount, line items, due date)

  3. 3

    System matches against open POs and checks for discrepancies

  4. 4

    Approved invoices are posted to accounting; exceptions routed for review

About ChatGPT / GPT-4o (OpenAI)

OpenAI's GPT-4o is the most widely deployed LLM. Excellent function calling, vision, and broad general capability.

Strengths

  • Function calling
  • Vision / multimodal
  • Broad ecosystem
  • Structured outputs

Pricing

Per token — gpt-4o: $2.50/$10 per 1M tokens in/out

Documentation ↗

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Want this in production?

Altor builds invoice processing automation for US B2B companies.

We don't hand off code and disappear. We connect to your live systems, ship to production in 3 weeks, and stay until the system delivers measurable impact. Invoice cycle time drops from days to minutes. Discrepancies caught before payment. Zero manual data entry.

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