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Invoice Maker API Documentation

Welcome to the Invoice Maker API documentation. Build powerful integrations with your invoicing workflow using our REST API and real-time Webhooks.

What you can do​

FeatureDescription
REST APICreate, read, and update invoices, quotations, and customers programmatically
WebhooksReceive real-time notifications when events happen in your account
Zapier / MakeConnect to 6,000+ apps using our API keys

Quick start​

1. Generate an API key​

Go to Integrations > API Keys in your Invoice Maker dashboard and create a new key. Copy the key immediately — it will only be shown once.

oim_a1b2c3d4e5f6...

2. Make your first API call​

curl -X GET https://onlineinvoicemaker.com/api/v1/invoices \
  -H "Authorization: Bearer oim_your_api_key_here"

3. Set up webhooks (optional)​

Go to Settings > Webhooks and add an endpoint URL. Select the events you want to receive, and we'll send real-time POST requests to your server.

Base URL​

All API requests are made to:

https://onlineinvoicemaker.com/api/v1

Authentication​

All requests require an API key passed via the Authorization header:

Authorization: Bearer oim_your_api_key_here

See Authentication for full details.

Rate limits​

PlanAPI KeysWebhook EndpointsWebhook Deliveries
Basic22100/hour
Pro20505,000/hour

Need help?​