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The Campfire and Numeral integration enables Zero Day Close by automating sales tax calculations and invoice processing. Once connected, Numeral automatically applies the correct sales tax rate to invoices created in Campfire and syncs transaction data back for compliance.

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Prerequisites

Before you begin, ensure you have:
  • A Campfire login with admin access (you need it to create an API user and to manage webhooks)
  • A Numeral account

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How the connection works

The connection has two halves, and tax only reaches your invoices when both are right:
  • A Campfire API key. Numeral uses it to read invoices and customers and to write the calculated tax back onto each invoice. The key belongs to a Campfire API user, and that user’s role decides what the key can do. A View only key lets Numeral read but not write, so tax shows up in Numeral and never in Campfire.
  • A Campfire webhook. Campfire uses it to tell Numeral when an invoice is created or updated. Campfire signs every event with the webhook’s secret, and Numeral checks that signature. If the secret saved in Numeral is not the one on the webhook, Numeral rejects every event and no tax is calculated.
Step 3 below checks both halves for you and creates a test invoice, so you do not have to guess which one is wrong.

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Step 1: Connect Numeral to Campfire

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Generate a Campfire API Key

The key must come from an API user with the Admin role (recommended) or the Clerk role. Both can edit invoices, so tax works with either. Only an Admin key also lets Numeral read your webhook back, so Numeral can verify it and fix a wrong secret for you in Step 3.
  1. Log in to your Campfire account.
  2. Navigate to Settings > API Keys (or go directly to https://app.meetcampfire.com/v2/settings/api-keys).
  3. Create an API user for Numeral and set its role to Admin. If you already have one, confirm its role is Admin or Clerk, not View only.
  4. Click Create API Key on that user.
  5. Copy the whole key. You will need it in the next step.
Do not use a key from a View only API user. Campfire accepts the key, but rejects Numeral’s tax write-back on every invoice, so tax appears in Numeral and never in Campfire. Numeral checks the key’s permissions when you connect and refuses a View only key with a message naming the role.
Store your API key securely. It will only be displayed once.

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Add the API Key to Numeral

  1. Log in to your Numeral account.
  2. Open Connections and click Add connection.
  3. Choose Campfire.
  4. Enter a name for your Campfire connection.
  5. Paste the whole Campfire API key, with no spaces or ellipses, and click Connect.
Numeral confirms the key can edit invoices before it continues. If it can, Numeral shows you a webhook URL, and you can proceed to the webhook setup step.

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Step 2: Set Up the Numeral Webhook in Campfire

The webhook is how Campfire tells Numeral about new and changed invoices. Without it, Numeral never hears about an invoice and never calculates tax.
  1. After connecting your API key in Numeral, you’ll be provided with a webhook URL.
  2. Click Copy Numeral webhook URL to copy it to your clipboard.
  3. In your Campfire account, navigate to Settings > Developer > Webhooks (or go directly to https://app.meetcampfire.com/v2/settings/webhooks).
  4. Click New Webhook.
  5. Paste the Numeral webhook URL into the webhook URL field and check Active.
  6. Subscribe the webhook to only the Invoice topics:
    • Created — When a new invoice is created
    • Updated — When an invoice is updated
    • Payment Updated — When payment status changes
  7. Save the webhook. Campfire generates a signing secret and shows it on the webhook card as HMAC-SHA256 Secret.
  8. Click Show next to the secret and copy the whole value.
  9. Return to Numeral and paste it into the Webhook Secret field.
  10. Click Continue to complete the setup.
The secret must be the one on this webhook’s card. A secret from an older webhook, a webhook that points at a previous Numeral connection, or a partial copy fails verification on every event, and no tax is calculated. Numeral rejects values that are clearly not a Campfire secret (too short, or containing spaces or ...) when you paste them.
If you reconnect Campfire later, Numeral gives the new connection a new webhook URL. Create a new webhook in Campfire for that URL (or update the existing one) and paste that webhook’s secret. The old webhook’s secret will not work.

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Step 3: Test Your Integration

Numeral can check the connection and run a real invoice through it, so you can confirm everything works before your first customer invoice.
  1. In Numeral, open Connections.
  2. Click the ⋯ menu on your Campfire connection and choose Integrations.
  3. Under Test your integration, click Run test.

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What the test checks

Before it creates anything, the test runs a checklist against your Campfire account: When the webhook is switched off or its secret does not match, the row shows a Fix this for me button. Numeral copies the right secret from Campfire and switches the webhook back on, with no reconnect needed. A missing webhook or a missing Invoice topic is fixed in Campfire under Settings > Developer > Webhooks.
Numeral can only read your webhook back with an Admin API key. With a Clerk key, the webhook row says it cannot be verified; tax still works, and the test invoice below still tells you whether the webhook is delivering.

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Create a test invoice

Once the checklist passes, click Create test invoice. Numeral creates a customer named Numeral Test Customer in Dallas, Texas and a $100 open invoice for one unit of one of your products, then applies tax to it the same way it does for your real invoices.
  • The invoice is never sent to anyone, and Campfire’s other tax connections are excluded from it.
  • The test always calculates Dallas tax, even if you do not collect in Texas. Real invoices follow your collection settings.
  • Within a few seconds the window shows Tax applied with the amount Numeral added, and a link to open the invoice in Campfire so you can see the tax on the line item.
If the window keeps showing No tax applied yet, Campfire’s webhook did not deliver the invoice to Numeral. Re-run the checklist, and confirm the webhook is active and subscribes to the Invoice topics. If it shows Tax on this invoice did not come from Numeral, another tax tool connected to Campfire taxed the invoice first.

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Clean up

Click Delete test resources when you are done. Numeral deletes the test invoice (journal entry included) and the test customer from your Campfire account. Numeral also deletes them automatically 24 hours after they were created. If a payment was recorded against the test invoice, Numeral voids it instead, and the voided invoice stays visible in Campfire because Campfire keeps a voided invoice’s record.

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Step 4: How Automated Tax Works on Invoices

Once the integration is complete, Numeral automatically calculates and adds sales tax to your invoices based on your configured tax rules. When you create or update an invoice in Campfire:
  1. Campfire sends the invoice data to Numeral via the webhook.
  2. Numeral identifies the customer’s location.
  3. The system applies the appropriate sales tax rate.
  4. The tax amount is calculated and added to the invoice.
  5. The complete transaction data (including tax breakdown) is synchronized back to Campfire.
What you’ll see:
  • In Campfire: Invoices will display itemized sales tax amounts calculated by Numeral.
  • In Numeral: Transaction data will include detailed tax information for accounting and compliance purposes.

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Connection Status and Troubleshooting

The Campfire connection on the Connections page shows one of these statuses. Open the connection’s details for the full explanation and fix. If tax is missing on a specific invoice while the connection shows Calculations received, check that the customer on the invoice has a complete address. Numeral needs the customer’s location to calculate tax.