Invoices Online MCP server

Read clients, balances, invoices and jobcard status; create clients in Invoices Online. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.

Connect Invoices Online50 free tool calls a month

What can I ask?

Turn on the Invoices Online connector, then ask in plain words. The AI picks the tools.

What you can do with Invoices Online in Claude and ChatGPT

For businesses that run clients, jobcards and invoices in Invoices Online.

Check client balances

List the clients with their balance and opening balance. Open one to read its contact details and current balance.

Review a client's invoices and payments

Find the client id from the name and email, then read the invoices, payments and balance history of that client.

Track jobcard status

List the status names for a document type, then read the current status of one jobcard by its number.

Look up suppliers and inventory

List the suppliers with their balances, and the inventory items with their product codes.

Add a new client

Create a client with a name and an email. If a matching client exists, the API returns its id and adds no duplicate. No email is sent.

Changes data

How do I connect Invoices Online?

Before you connect

The login page asks for your Invoices Online API username and Invoices Online API password.

Find them in Invoices Online under Settings → API Access (invoicing mode). Copy both values exactly as shown. They are used only to call the API on your behalf and to derive a private account id; they are never shown to anyone.

Claude claude.ai · Desktop

  1. Open Customize → Connectors, then click + Add → Add custom connector.
  2. Enter the name Invoices Online and this URL, then click Add:
    https://invoices-online.usefulapi.io/mcp
  3. Claude opens the login page: enter your Invoices Online API username and Invoices Online API password.
  4. In a chat, click + → Connectors and turn on Invoices Online.

Team and Enterprise: an Owner adds the connector for the organization first.

ChatGPT chatgpt.com

  1. Open Plugins, click +, then Add custom MCP server.
  2. Enter the name Invoices Online and this URL, choose OAuth as the authentication, confirm the warning and create it:
    https://invoices-online.usefulapi.io/mcp
  3. ChatGPT opens the login page: enter your Invoices Online API username and Invoices Online API password.
  4. In Plugins, install Invoices Online, then choose it in a chat.

No Add custom MCP server option? It depends on your account or workspace settings: see OpenAI's guide.

Claude Code

Run this command, then run /mcp in Claude Code to log in:

claude mcp add --transport http invoices-online https://invoices-online.usefulapi.io/mcp

Cursor

Add to Cursor or add this to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "invoices-online": {
      "url": "https://invoices-online.usefulapi.io/mcp"
    }
  }
}

VS Code

Add to VS Code or add this to .vscode/mcp.json:

{
  "servers": {
    "invoices-online": {
      "type": "http",
      "url": "https://invoices-online.usefulapi.io/mcp"
    }
  }
}

Codex

Run these commands. The second one opens the login page:

codex mcp add invoices-online --url https://invoices-online.usefulapi.io/mcp
codex mcp login invoices-online

Other clients

Windsurf, Cline, Zed and other MCP clients: add this URL as a remote MCP server (Streamable HTTP). The client then opens the login page in your browser.

https://invoices-online.usefulapi.io/mcp

Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your Invoices Online API username and Invoices Online API password. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.

Pricing

PlanPriceLimit
Free$050 tool calls / month
Proper user$9/mo · $90/yr10,000 tool calls / month
Pro+per user$39/mo · $390/yr100,000 tool calls / month

Each paid plan covers this Invoices Online server only. Ask your AI to run invoicesonline_upgrade and choose Pro or Pro+, billed monthly or yearly (it returns a Stripe Checkout link). If you already have Pro, ask to change it to Pro+. The change requires your confirmation, keeps your billing interval and charges the price difference for the rest of the period immediately. Cancel any time with invoicesonline_cancel_subscription: your paid plan continues to the end of the paid period, with no refund for the current period, and asking to resume the same plan with invoicesonline_upgrade before then undoes the cancel. Or write to support@usefulapi.io.

Tools 17

Show all 17 tools (the AI picks them for you)

Read only · 12

  • Get businessinvoicesonline_get_business
    Get the id and name of the Invoices Online business this API login belongs to. Read only. Endpoint: getBusinessName.php.
  • List clientsinvoicesonline_list_clients
    List every client of the business: name, contact, email, VAT number, addresses, active flag, balance and opening balance. Read only. Endpoint: getClients_JSON.php.
  • Get a clientinvoicesonline_get_client
    Get one client by client_id: contact details, active flag, current balance and opening balance. Read only. Endpoint: getClientDetails_JSON.php.
  • Find a client idinvoicesonline_find_client_id
    Look up the client_id from the invoice name, email and branch name. Read only. Endpoint: GetClientID.php. Returns the id, or the vendor's error text when no client matches.
  • Get client historyinvoicesonline_get_client_history
    List a client's invoices, credit notes, pro-forma invoices, payments and payouts with totals and line items, plus the current and opening balance. Read only. Endpoint: getClientHistory_JSON.php.
  • List client documentsinvoicesonline_list_client_documents
    List one client's documents of one type (invoices, quotes, credit notes, jobcards, and so on). Read only. Endpoint: getDocumentsByType_JSON.php.
  • List suppliersinvoicesonline_list_suppliers
    List every supplier of the business with contact details, active flag, balance and opening balance. Read only. Endpoint: getSuppliers_JSON.php.
  • Get a supplierinvoicesonline_get_supplier
    Get one supplier by supplier_id: contact details, active flag, balance and opening balance. Read only. Endpoint: getSupplierDetails_JSON.php.
  • List inventory itemsinvoicesonline_list_inventory_items
    List the inventory and stock items keyed by product code. Read only. Endpoint: InventoryItems.php.
  • List inventory categoriesinvoicesonline_list_inventory_categories
    List the inventory categories keyed by category id. Read only. Endpoint: InventoryCategories.php.
  • List document status idsinvoicesonline_get_document_status_ids
    List the status ids and their names for one document type. Read only. Endpoint: getDocumentStatusIDs.php.
  • Get a jobcard statusinvoicesonline_get_document_status
    Get the current status name and status id of one jobcard by its number. Read only. Endpoint: getDocumentStatus.php. Only jobcard is supported.

Changes data · 1

  • Create a clientinvoicesonline_create_client
    Create a client in the business. Writes data. Only the invoice name and email are required. If the API finds a matching client, it returns that client's id and creates no duplicate. Endpoint: NewClient.php. Sends no email.

Your usefulapi plan · 4

  • Usage status (free-tier meter)invoicesonline_usage_status
    Report the caller's current usage: the plan, calls used this month, the limit of the plan (the free monthly cap or the Pro fair use limit), remaining, and whether the limit is reached. Read-only; does not count against the meter.
  • Request a missing featureinvoicesonline_request_feature
    Tell usefulapi that the user needs something the Invoices Online tools cannot do yet (a missing tool, field or filter). Call it only when the user asks for something none of the tools can do, and tell the user that you send the request. Do not call it for errors or for normal requests. Do not include personal data, credentials or customer records. Stored with the product name and the client type (for example Claude or Cursor), without the user's account. At most 5 requests per day. Does not count against the meter.
  • Upgrade to Pro or Pro+invoicesonline_upgrade
    Get a paid plan for Invoices Online (the free tier caps monthly usage). Pro: 10,000 tool calls a month, for normal use — plan "monthly" ($9/month) or "yearly" ($90/year, 2 months free). Pro+: 100,000 tool calls a month, for automations and heavy use — plan "plus" ($39/month) or "plus_yearly" ($390/year). Without a plan it returns both Pro and Pro+, each with a payment link, for the user to choose; with a plan, one link. An existing Pro subscription changes to Pro+ in place: call without confirm first, as the reply states the exact charge for this account (the price difference for the rest of the period, or in a free Pro trial the full Pro+ price, as the trial ends); then call with confirm: true. Cancel any time: the plan then runs to the end of the paid period, so it also suits a one-time job. A link opens Stripe Checkout in the browser; after payment the account upgrades automatically. Does not count against the meter.
  • Cancel the Pro subscriptioninvoicesonline_cancel_subscription
    Cancel the caller's Invoices Online Pro subscription at the end of the paid period (no refund for the current period; Pro continues until then, then the free tier applies). Requires confirm: true. Run invoicesonline_upgrade later to undo the cancel before the period ends. Does not count against the meter.

FAQ

What can I do with Invoices Online in Claude or ChatGPT?

Check client balances. Review a client's invoices and payments. Track jobcard status. Look up suppliers and inventory. Add a new client. See what you can do for the details.

Is this an official Invoices Online product?

No. usefulapi is an independent service. It is not affiliated with or endorsed by Invoices Online. The server calls the Invoices Online API with your own Invoices Online access, so it sees only the data that your account can see.

Can I connect Invoices Online to Claude or ChatGPT?

Yes. In Claude, add this server's URL as a custom connector. In ChatGPT, add it as a custom MCP server in Plugins. Then log in once. Cursor, VS Code, Claude Code and Codex work too. See the setup steps.

What do I need to connect?

The login page asks for your Invoices Online API username and Invoices Online API password. See Before you connect for where to find them.

Do I put my Invoices Online key or an Authorization header in the client config?

No. Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your Invoices Online API username and Invoices Online API password. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.

How do you keep my Invoices Online credentials?

The login stores them encrypted in the authorization grant of your connection. The server uses them to call the Invoices Online API for you and to derive a private account id for usage metering. usefulapi does not show them on any page or in any reply. To stop all access, remove the connector and change or delete these credentials in Invoices Online.

Can the AI change my Invoices Online data?

Yes, if you approve it. 1 of the 13 Invoices Online tools can create or change data. The other 12 are marked read-only. Most MCP clients ask you to approve a tool call before it runs.

What does it cost?

The Free plan gives 50 tool calls / month. Pro costs $9/mo or $90/yr, with 10,000 tool calls / month. Pro+ costs $39/mo or $390/yr, with 100,000 tool calls / month. Each subscription covers this Invoices Online server only. Cancel any time: your paid plan then runs to the end of the paid period. Run invoicesonline_usage_status to see how many calls you used.

How do I subscribe or cancel?

Ask the AI to run invoicesonline_upgrade and choose Pro or Pro+, billed monthly or yearly: it returns a Stripe Checkout link. If you already have Pro, ask to change it to Pro+. After you confirm, your existing subscription changes in place, keeps its billing interval and charges the price difference for the rest of the period immediately. To cancel, run invoicesonline_cancel_subscription. Your paid plan continues to the end of the paid period.

What if a Invoices Online tool that I need is missing?

Tell the AI what you wanted to do. It can send the request with invoicesonline_request_feature. We store the text with the server name, the type of AI client and the tool you tried, not with your account, and read every request when we plan new tools. You can send up to 5 requests per day.

Which AI clients can I use?

Any client that supports remote MCP servers (Streamable HTTP) with OAuth login: Claude (web and desktop), Claude Code, ChatGPT, Codex, Cursor, VS Code, Windsurf and others.

This is a Model Context Protocol endpoint — meant to be connected from an AI client, not opened in a browser. An invalid_token response at the URL is the auth gate working as designed; clients authenticate automatically.

Need a tool this server does not have, or a connection to another system? We build custom integrations and MCP servers.

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