# Connect ChatGPT to LotsInvoice Canonical page: https://lotsinvoice.com/agents/chatgpt Steps checked: 2026-10-16 Ask ChatGPT to draft invoices, check who owes you and record payments in LotsInvoice. Add LotsInvoice to ChatGPT as a remote MCP server and sign in once. MCP server URL: https://api.lotsinvoice.com/mcp REST API docs: https://api.lotsinvoice.com/docs Setup instructions for your agent: https://lotsinvoice.com/skill.md ## What you can do once connected - Draft invoices, estimates and credit notes for your customers, with the totals worked out for you. - Turn an estimate into an invoice, and repeat an invoice on a schedule, such as a monthly retainer. - Email an invoice or a payment reminder to your customer when you tell it to. - See who owes you and how late each invoice is, and record the payments you receive. - Add customers and saved items, and set up your taxes and payment options from the details you give it. - Pull revenue, tax and payment reports and customer statements for your accountant. The LotsInvoice dashboard does the whole job on its own: invoices, estimates, customers, payments, reminders and reports. Every invoice your agent drafts shows up there, where you can check the PDF preview before you send it. ## You need - Adding a custom connector with full read and write depends on your ChatGPT plan, and on some plans only admins can add one. Check OpenAI’s current plan details. - A LotsInvoice account. You can create one during sign-in. ## Connect ChatGPT to LotsInvoice 1. **Add a custom MCP server.** In ChatGPT on the web, go to Plugins, select +, then Add custom MCP server. 2. **Enter the LotsInvoice connection.** Name it LotsInvoice. Under Connection, enter the server URL below, then choose OAuth for authentication. Tick I understand and want to continue, then select Create as a plugin. ``` https://api.lotsinvoice.com/mcp ``` 3. **Install it and sign in.** Install the LotsInvoice plugin, click Connect and sign in to LotsInvoice. New users can create an account during this step. Allow ChatGPT to use LotsInvoice when prompted. 4. **Use it in a chat.** In a new chat, type @, select LotsInvoice and ask for something read-only first. ``` Show me what needs attention in my LotsInvoice business ``` ## What to ask next - “Draft an invoice for Acme Design for 12 hours of design work, due in 15 days. Show me the total first.” - “Which invoices are overdue? Show me a friendly reminder for each one before you send anything.” - “Turn the estimate for Northwind into an invoice and set it to repeat on the 1st of every month.” - “Record a bank transfer from Northwind against their open invoice.” ## Questions and troubleshooting ### How do I connect ChatGPT to LotsInvoice? In ChatGPT on the web, go to Plugins, select +, then Add custom MCP server. Name it LotsInvoice, enter https://api.lotsinvoice.com/mcp under Connection, choose OAuth, tick I understand and want to continue and select Create as a plugin. Install it, sign in, then in a new chat type @, select LotsInvoice and ask “Show me what needs attention in my LotsInvoice business”. Adding a custom connector with full read and write depends on your ChatGPT plan, and on some plans only admins can add one. Check OpenAI’s current plan details. ### Can I connect LotsInvoice with a Free or Go ChatGPT account? Adding a custom connector with full read and write depends on your ChatGPT plan, and on some plans only admins can add one. Check OpenAI’s current plan details. You can also connect LotsInvoice to Claude or another MCP agent. ### Do I need an API key to use LotsInvoice with ChatGPT? No. ChatGPT signs in to LotsInvoice in your browser. API keys are for the REST API, for scripts and your own apps. ### What does LotsInvoice cost? Current plans and prices are on https://lotsinvoice.com/pricing. Your agent’s own plan or usage fees are separate. ### Will my agent email my customers without asking me? Every invoice starts as a draft, and nothing reaches your customer until it is sent. Sending is its own step, and the LotsInvoice tools and skill tell your agent to show you the totals and ask before it sends. You can also open the draft in your dashboard first. ### Does LotsInvoice take or move money through my agent? No. LotsInvoice never holds or moves your money. Your customers pay you directly with the payment options you set up, and your agent can record a payment once you have received it. ### Can my agent change an invoice I already sent? A sent invoice is locked with its number. Your agent can revise it with a reason, which keeps the number and adds a version, or void it. A paid invoice is corrected with a credit note. ### Does my agent choose my tax rates? No. It uses the taxes you have set up or the rates you give it, and it asks for anything that is missing. Check your layout and tax wording with your accountant. ### I cannot find Add custom MCP server If you can’t add the connector: Adding a custom connector with full read and write depends on your ChatGPT plan, and on some plans only admins can add one. Check OpenAI’s current plan details. ### ChatGPT does not use LotsInvoice in my chat In a new chat, type @ and select LotsInvoice, confirm it is connected and finish any authorization prompt. Ask ChatGPT “Show me what needs attention in my LotsInvoice business” before anything else. If ChatGPT still can’t use its tools, your ChatGPT plan may not allow custom connectors with full read and write. Check OpenAI’s current plan details. ## Sources - [OpenAI: Connect and test your plugin](https://developers.openai.com/plugins/deploy/connect-chatgpt) - [OpenAI: Connecting custom MCP servers in ChatGPT](https://help.openai.com/en/articles/12584461-connecting-custom-mcp-servers-in-chatgpt)