Read a PDF with AI and have the sender confirm it

The pattern fits any document someone sends you: an order, a claim, an application, a contract to check. Checked on self-hosted n8n 2.44 with version 0.13.0 of the node.

Before you start

• The Formstep node on a self-hosted n8n with a public HTTPS address, and a Formstep credential. On n8n Cloud, call the REST API from an HTTP Request node instead; see n8n Cloud.
• A credential for a chat model in n8n: Anthropic, OpenAI, Google Gemini or any other the AI nodes take.
• A form for the confirmation. In Formstep, open Templates, pick Confirm Invoice Details, click Use template and publish it. Its field keys are supplier_name, invoice_number, invoice_date, due_date, total_amount, confirmed and notes, and it has a Documents block for the invoice.

Import the workflow from

with Import from File. The example pins a sample result on the AI node, so it runs before you add a model; unpin it once your model is connected.

1. Get the PDF

The example downloads a sample invoice with an HTTP Request node, Response Format File, and takes the supplier’s address from an Edit Fields node named Invoice. In your workflow it is usually a Gmail or Outlook trigger on the invoices inbox, with the attachment in a binary field and the sender as the recipient, or a new file in a Google Drive folder.

2. Extract the text

Add an Extract from File node with Operation Extract From PDF. It reads the PDF’s text into {{ $json.text }}.

3. Read it with AI

Add an Information Extractor node, connect your chat model to it, and set Text to {{ $json.text }}. Under Attributes, add one attribute per value you want, named after the field key it fills:

The node returns what it read under {{ $json.output }}, as {{ $json.output.total_amount }}. Naming the attributes after the field keys keeps the mapping in the next step one to one.

4. Put the file back

The Information Extractor returns what it read, not the PDF. To attach the invoice to the request, add a Merge node with Mode Combine and Combine By Position. Connect the HTTP Request node to input 1 and the Information Extractor to input 2. Each item then has the file in data and the reading in output.

5. Ask the supplier to confirm

Add a Formstep Create request node and pick the Confirm Invoice Details form. Set Recipient Email to the supplier’s address, map each field under Values to Send to its value, like {{ $json.output.invoice_number }}, and add a document from the binary field data, named Invoice {{ $json.output.invoice_number }}. Turn on Wait for the Outcome and add a Wait node after it, Resume On Webhook Call.

Dates and the amount arrive in their own inputs: the date fields take 2026-10-20, the amount a number. The supplier sees every value filled in, with the invoice above them, and fixes what is wrong:

Formstep emailing the supplier needs Pro or Business. On Free, leave Delivery at None and send the request’s url with your own email node; see Invitations and reminders. The request expires after 30 days unless you set Expires At, so set it sooner for an invoice due in two weeks; see Expiry.

6. See what was corrected

Add an If node that checks {{ $json.body.type }} is request.completed, and on its true output a Code node that compares the AI’s reading with the confirmed answers:

// Compare what the AI read with what the supplier confirmed.
const read = $('Read the invoice with AI').item.json.output
const confirmed = $json.body.data.answers
const corrected = Object.keys(read).filter((key) => String(read[key]) !== String(confirmed[key]))
return { json: { invoice: confirmed, corrected, notes: confirmed.notes ?? null } }

In the test run the model read the total as 27 235. The supplier corrected it to 27 325 and left a note, so corrected lists total_amount:

From here, book the invoice with invoice in your accounting tool, and send the ones where corrected is not empty to a person for a second look. The false output of the If node catches a request that expired: chase the supplier there.

Variations

• For documents nobody outside should see again, send the request to someone on your team rather than the sender.

• Lock what you are sure of. Values from your own system, like the order number you issued, go under Read-Only Field Names or IDs, so only the AI’s reading is open to correction.

• An If node before the request can send readings that fail the arithmetic to your team instead of the supplier.

• With no form yet, set Form Source to New Form and build the form from the attributes; see Collect the documents each case needs. To show the invoice above the values, use a published form.

Next steps