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How to Automate Expense Reimbursement with n8n and Receipt Parser API

#ai #productivity #programming #api

Target keywords: n8n receipt automation, automate expense reimbursement workflow, n8n HTTP node API
Platform: dev.to (primary) + n8n Community Discord #showcase + Hashnode (cross-post)
Word count target: 1,200–1,500 words
Meta title (60 chars): Automate Expense Reimbursement with n8n + Receipt API
Meta description (155 chars): Build an n8n workflow that parses receipt images, extracts structured data, and routes them for approval — no code required. Step-by-step tutorial.

The API powering this workflow — try it before you build:
👉 ilovesreceipt.com
Upload any receipt and see the structured JSON output in seconds.

What We're Building

An n8n workflow that:

  1. Triggers when a receipt image is submitted (email attachment, Google Drive upload, or webhook)
  2. Parses the receipt using the Receipt Parser API → returns structured JSON
  3. Routes based on amount: auto-approves small expenses, flags large ones for manager review
  4. Logs every expense to a Google Sheet
  5. Notifies the submitter via Slack or email with the parsed details

No code required. Pure n8n nodes.

Prerequisites

  • n8n instance (cloud or self-hosted — n8n.io)
  • Receipt Parser API key from ilovesreceipt.com (free tier: 500 calls/month)
  • Google account (for Sheets logging)
  • Optional: Slack workspace for notifications

Workflow Overview 

[Trigger] → [HTTP Request: Parse Receipt] → [IF: Amount > $50?]
                                                 ├── YES → [Slack: Flag for Review]
                                                 └── NO  → [Google Sheets: Log Expense]
                                                                    ↓
                                               [Gmail/Slack: Notify Submitter]
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Step 1: Set Up the Trigger

Choose your entry point based on how employees submit receipts:

Option A — Webhook (most flexible):
Add a Webhook node. Set method to POST. This lets you trigger the workflow from any tool (form, mobile app, Zapier) that can send a webhook.

Option B — Gmail (receipts by email):
Add a Gmail Trigger node. Filter by subject containing "receipt" or "reimbursement". The workflow fires each time a matching email arrives with an attachment.

Option C — Google Drive:
Add a Google Drive Trigger node. Watch a specific folder (e.g., /Receipts/Pending). Fires when any new file is uploaded.

For this tutorial we'll use the Webhook option since it's the most reusable.

Step 2: Read the File

No conversion needed. The Receipt Parser API accepts the raw file directly as multipart/form-data — no base64 encoding required.

If your trigger provides a URL (e.g. a Google Drive file URL), add an HTTP Request node set to GET to download the binary first. If your trigger provides a binary attachment directly (e.g. Gmail attachment), pipe it straight into Step 3.

Step 3: Call the Receipt Parser API

Add an HTTP Request node with these settings:

Field Value
Method POST
URL https://web-production-58295.up.railway.app/api/parse
Authentication Header Auth
Header name Authorization
Header value Bearer {{ $credentials.receiptParserKey }}
Body Content Type Form Data (multipart)
Body field name file
Body field value (binary data from previous node)

Tip: Store your API key in n8n Credentials as a Generic Credential with Authorization → Bearer YOUR_KEY. This keeps it secure and reusable across workflows. Get your free key at ilovesreceipt.com — 500 calls/month, no credit card required.

After this node runs, you'll have the full parsed JSON available in subsequent nodes as $json.data.merchant.name, $json.data.total, etc.

Step 4: Add Routing Logic (IF Node)

Add an IF node to route based on the expense amount:

Condition:

{{ $json.data.total }} > 50
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  • True branch → flag for manager review (high expense)
  • False branch → auto-approve and log

You can layer additional conditions:

  • Category-based routing (meals vs. travel vs. supplies)
  • Merchant allowlist/blocklist
  • Employee-specific thresholds

Step 5: Log to Google Sheets

On the False (auto-approved) branch, add a Google Sheets node:

  • Operation: Append Row
  • Spreadsheet: your expense log sheet
  • Sheet: Expenses

Map these columns:

Column Value
Date {{ $json.data.date }}
Merchant {{ $json.data.merchant.name }}
Total {{ $json.data.total }}
Tax {{ $json.data.tax }}
Tip {{ $json.data.tip }}
Payment {{ $json.data.payment_method }}
Status Auto-Approved
Submitted {{ $now }}

Step 6: Flag for Manager Review (Slack)

On the True (high expense) branch, add a Slack node:

  • Operation: Send Message
  • Channel: #expense-approvals
  • Message: 
🧾 *Expense Approval Required*

*Merchant:* {{ $json.data.merchant.name }}
*Amount:* ${{ $json.data.total }}
*Date:* {{ $json.data.date }}
*Payment:* {{ $json.data.payment_method }}

React ✅ to approve or ❌ to reject.
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Step 7: Notify the Submitter

On both branches, add a Gmail or Slack node to confirm receipt:

Hi there — your expense was received and parsed successfully.

Merchant: {{ $json.data.merchant.name }}
Date: {{ $json.data.date }}
Total: ${{ $json.data.total }}

{{ $json.data.total > 50 ? "Your expense has been flagged for manager review." : "Your expense has been auto-approved and logged." }}
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The Complete Workflow (JSON Import)

You can import this workflow directly into n8n. Copy the JSON below and use File → Import from JSON in n8n:

Download receipt-expense-reimbursement.json

After importing, you'll need to:

  1. Create a Header Auth credential named Receipt Parser API with Authorization: Bearer YOUR_KEY — get your free key at ilovesreceipt.com
  2. Connect your Slack Account credential and update the channel names
  3. Connect your Google Sheets Account credential and replace YOUR_SPREADSHEET_ID with your actual sheet ID 
{
  "name": "Receipt Expense Reimbursement",
  "nodes": [
    {
      "id": "1a2b3c4d-0000-0000-0000-000000000000",
      "name": "Setup Instructions",
      "type": "n8n-nodes-base.stickyNote",
      "typeVersion": 1,
      "position": [240, 80],
      "parameters": {
        "width": 760,
        "height": 180,
        "content": "## ⚙️ Setup Required Before Running\n1. **Receipt Parser API** — Create a *Header Auth* credential named `Receipt Parser API`. Set header name to `Authorization`, value to `Bearer YOUR_API_KEY`. Get a free key (500 calls/month) at **ilovesreceipt.com**\n2. **Slack Account** — Connect your Slack workspace in Credentials. Update `#expense-approvals` and `#YOUR_CHANNEL` to real channel names.\n3. **Google Sheets** — Connect your Google account in Credentials. Replace `YOUR_SPREADSHEET_ID` with your actual spreadsheet ID (found in the sheet URL)."
      }
    },
    {
      "id": "1a2b3c4d-0001-0000-0000-000000000001",
      "name": "Receipt Submitted",
      "type": "n8n-nodes-base.webhook",
      "typeVersion": 2,
      "position": [240, 320],
      "webhookId": "receipt-parse-webhook-001",
      "parameters": {
        "httpMethod": "POST",
        "path": "receipt-parse",
        "responseMode": "onReceived",
        "options": {}
      }
    },
    {
      "id": "1a2b3c4d-0002-0000-0000-000000000002",
      "name": "Parse Receipt via API",
      "type": "n8n-nodes-base.httpRequest",
      "typeVersion": 4,
      "position": [460, 320],
      "parameters": {
        "method": "POST",
        "url": "https://web-production-58295.up.railway.app/api/parse",
        "authentication": "genericCredentialType",
        "genericAuthType": "httpHeaderAuth",
        "sendBody": true,
        "contentType": "multipart-form-data",
        "bodyParameters": {
          "parameters": [
            {
              "parameterType": "formBinaryData",
              "name": "file",
              "inputDataFieldName": "data"
            }
          ]
        },
        "options": {}
      },
      "credentials": {
        "httpHeaderAuth": {
          "id": "receipt-parser-api-cred",
          "name": "Receipt Parser API"
        }
      }
    },
    {
      "id": "1a2b3c4d-0003-0000-0000-000000000003",
      "name": "Amount > $50?",
      "type": "n8n-nodes-base.if",
      "typeVersion": 2,
      "position": [680, 320],
      "parameters": {
        "conditions": {
          "options": {
            "caseSensitive": true,
            "leftValue": "",
            "typeValidation": "loose"
          },
          "conditions": [
            {
              "id": "amount-check",
              "leftValue": "={{ $json.data.total }}",
              "rightValue": 50,
              "operator": {
                "type": "number",
                "operation": "gt"
              }
            }
          ],
          "combinator": "and"
        }
      }
    },
    {
      "id": "1a2b3c4d-0004-0000-0000-000000000004",
      "name": "Flag for Manager Review",
      "type": "n8n-nodes-base.slack",
      "typeVersion": 2,
      "position": [900, 180],
      "parameters": {
        "operation": "postMessage",
        "channel": "#expense-approvals",
        "text": "=🧾 *Expense Approval Required*\n\n*Merchant:* {{ $json.data.merchant.name }}\n*Amount:* ${{ $json.data.total }}\n*Date:* {{ $json.data.date }}\n*Payment:* {{ $json.data.payment_method }}\n\nReact ✅ to approve or ❌ to reject.",
        "otherOptions": {}
      },
      "credentials": {
        "slackApi": {
          "id": "slack-account-cred",
          "name": "Slack Account"
        }
      }
    },
    {
      "id": "1a2b3c4d-0005-0000-0000-000000000005",
      "name": "Log to Google Sheets",
      "type": "n8n-nodes-base.googleSheets",
      "typeVersion": 4,
      "position": [900, 460],
      "parameters": {
        "operation": "appendOrUpdate",
        "documentId": {
          "__rl": true,
          "value": "YOUR_SPREADSHEET_ID",
          "mode": "id"
        },
        "sheetName": {
          "__rl": true,
          "value": "Expenses",
          "mode": "name"
        },
        "columns": {
          "mappingMode": "defineBelow",
          "value": {
            "Date": "={{ $json.data.date }}",
            "Merchant": "={{ $json.data.merchant.name }}",
            "Total": "={{ $json.data.total }}",
            "Tax": "={{ $json.data.tax }}",
            "Tip": "={{ $json.data.tip }}",
            "Payment": "={{ $json.data.payment_method }}",
            "Status": "Auto-Approved",
            "Submitted": "={{ $now }}"
          }
        },
        "options": {}
      },
      "credentials": {
        "googleSheetsOAuth2Api": {
          "id": "google-sheets-account-cred",
          "name": "Google Sheets Account"
        }
      }
    },
    {
      "id": "1a2b3c4d-0006-0000-0000-000000000006",
      "name": "Notify Submitter",
      "type": "n8n-nodes-base.slack",
      "typeVersion": 2,
      "position": [1120, 320],
      "parameters": {
        "operation": "postMessage",
        "channel": "#YOUR_CHANNEL",
        "text": "=Hi there — your expense was received and parsed successfully.\n\nMerchant: {{ $json.data.merchant.name }}\nDate: {{ $json.data.date }}\nTotal: ${{ $json.data.total }}\n\n{{ $json.data.total > 50 ? \"Your expense has been flagged for manager review.\" : \"Your expense has been auto-approved and logged.\" }}",
        "otherOptions": {}
      },
      "credentials": {
        "slackApi": {
          "id": "slack-account-cred",
          "name": "Slack Account"
        }
      }
    }
  ],
  "connections": {
    "Receipt Submitted": {
      "main": [
        [{ "node": "Parse Receipt via API", "type": "main", "index": 0 }]
      ]
    },
    "Parse Receipt via API": {
      "main": [
        [{ "node": "Amount > $50?", "type": "main", "index": 0 }]
      ]
    },
    "Amount > $50?": {
      "main": [
        [{ "node": "Flag for Manager Review", "type": "main", "index": 0 }],
        [{ "node": "Log to Google Sheets", "type": "main", "index": 0 }]
      ]
    },
    "Flag for Manager Review": {
      "main": [
        [{ "node": "Notify Submitter", "type": "main", "index": 0 }]
      ]
    },
    "Log to Google Sheets": {
      "main": [
        [{ "node": "Notify Submitter", "type": "main", "index": 0 }]
      ]
    }
  },
  "active": false,
  "settings": { "executionOrder": "v1" },
  "meta": { "instanceId": "" }
}
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Testing the Workflow

  1. Open the workflow in n8n
  2. Click Execute Workflow with test mode on
  3. Send a POST request to your webhook URL with a receipt image: 
curl -X POST https://your-n8n-instance.com/webhook/receipt-parse \
  -F "data=@receipt.jpg"
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  1. Check your Google Sheet for the logged row and Slack for any approval notifications.

Going Further

  • Multi-currency support: The API detects currency — add a conversion step using an exchange rate API
  • PDF invoices: The API handles PDFs too — great for contractor invoices submitted via email attachment
  • Airtable instead of Sheets: Swap the Google Sheets node for an Airtable node for richer filtering
  • Approval loop: Use n8n's Wait node to pause the workflow until a Slack reaction is received

Try the API First

Before building the workflow, see what the parsed JSON looks like for your receipt types:

👉 Live Demo — no signup required

Ready to start building? Get your free API key at ilovesreceipt.com — 500 calls/month, no credit card required.

Built this workflow or have a question about a specific node? Share it in the comments — I'll help debug.

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