Collmex MCP server

Review Collmex customers, products, invoices and orders; create customers and addresses. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.

Connect CollmexFree 50 tool calls / monthPro $9/mo · $90/yr · pricing19 tools

What can I ask?

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

Which customer invoices are still open and how many days overdue are they?
Show all invoices to customer 12345 from the last quarter.
How much stock is available for product A-100?
Create a new customer Muster GmbH, Hauptstr. 1, 10115 Berlin, DE.

What you can do with Collmex in Claude and ChatGPT

For small businesses reviewing accounting, customer and stock records in Collmex.

Review overdue balances

Read open customer or supplier items with due dates, days overdue and outstanding amounts to decide which balances need attention.

Check stock before quoting

Look up a product and its available stock, accounting for demand due today or earlier. Service products may have no stock quantity.

Review a customer order

Find sales orders by customer, order number or date range and review their status and positions. This does not change fulfillment or accounting.

Create a customer after checking for duplicates

Search for the customer first, then create a new record with the requested company or person details. Collmex assigns a new customer number; no message is sent.

Changes data

How do I connect Collmex?

Before you connect

The login page asks for your Collmex customer number, API user name and API user password.

In Collmex create a separate user for this connection under Verwaltung → Benutzer and tick Nur für API (Collmex requires it for API access, and such users cost nothing extra). The user acts with that user's permissions. Collmex allows 10,000 API calls per day per customer number. Your login is used only to call the Collmex API on your behalf; it is never shown to anyone.

Claude claude.ai · Desktop

Open Customize → Connectors, then click + Add → Add custom connector.
Enter the name Collmex and this URL, then click Add:
https://collmex.usefulapi.io/mcp
Claude opens the login page: enter your Collmex customer number, API user name and API user password.
In a chat, click + → Connectors and turn on Collmex.

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

ChatGPT chatgpt.com

Open Plugins, click +, then Add custom MCP server.
Enter the name Collmex and this URL, choose OAuth as the authentication, confirm the warning and create it:
https://collmex.usefulapi.io/mcp
ChatGPT opens the login page: enter your Collmex customer number, API user name and API user password.
In Plugins, install Collmex, 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 collmex https://collmex.usefulapi.io/mcp

Cursor

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

{
  "mcpServers": {
    "collmex": {
      "url": "https://collmex.usefulapi.io/mcp"
    }
  }
}

VS Code

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

{
  "servers": {
    "collmex": {
      "type": "http",
      "url": "https://collmex.usefulapi.io/mcp"
    }
  }
}

Codex

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

codex mcp add collmex --url https://collmex.usefulapi.io/mcp

codex mcp login collmex

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://collmex.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 Collmex customer number, API user name and API user 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

Plan	Price	Limit
Free	$0	50 tool calls / month
Proper Collmex account	$9/mo · $90/yr	10,000 tool calls / month
Pro+per Collmex account	$39/mo · $390/yr	100,000 tool calls / month

Each paid plan covers this Collmex server only. Ask your AI to run collmex_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 collmex_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 collmex_upgrade before then undoes the cancel. Or write to [email protected].

Tools 19

Show all 19 tools (the AI picks them for you)

Read only · 13

List customerscollmex_list_customers
Search Collmex customers (record CUSTOMER_GET): by customer number, free text (name, city, e-mail ...), postal code or country. Returns address, contact, bank (IBAN/BIC), VAT id, payment terms, agent and status fields. Inactive customers are left out unless asked for.
List vendorscollmex_list_vendors
Search Collmex vendors/suppliers (record VENDOR_GET): by vendor number, free text, postal code or country. Returns address, contact, bank, VAT id, payment terms and expense account fields.
List addressescollmex_list_addresses
Search the Collmex address book (record ADDRESS_GET): customers, vendors and address-book entries in one list, optionally with their contact persons. address_type: 0 all, 1 customers, 2 vendors, 3 address-book entries.
List productscollmex_list_products
Search Collmex products (record PRODUCT_GET): by product number, product group, free text (number, description, remark, GTIN, manufacturer) or price group. Returns description, unit, tax class, sales price, purchase data and stock settings.
Get available stockcollmex_get_available_stock
Currently available stock per product (record STOCK_AVAILABLE_GET): on-hand stock of the available stock types minus demand due today or earlier. A service product shows (NULL). Leave product_no empty for every product.
List invoicescollmex_list_invoices
Search Collmex customer invoices and credit notes (record INVOICE_GET): by invoice number, customer, invoice date range, customer order or product. Each invoice has its header (customer address, dates, payment terms, status code: 0 new, 10 to be posted, 20 open, 30 dunned, 40 settled, 100 deleted) and its positions with quantities, prices and values. Reads only; no PDF/XML export.
List sales orderscollmex_list_sales_orders
Search Collmex customer orders (record SALES_ORDER_GET): by order number, customer, order date range or the customer's own order number. Each order has its header (customer address, dates, payment terms, status code: 0 new, 10 confirmed, 30 paid, 50 delivered, 90 invoiced, 100 done, 1000 cancelled) and its positions. Reads only; no PDF export.
List payment termscollmex_list_payment_terms
The payment terms defined in Collmex (record TERMS_OF_PAYMENT_GET): number, description, payment method and discount periods. The number is what customers, vendors and invoices refer to as payment_terms.
List open itemscollmex_list_open_items
Open items (unpaid invoices) from the Collmex accounting (record OPEN_ITEMS_GET), for customers (receivables, default) or vendors (payables). Returns invoice number, document and due date, days overdue, dunning level, amount, paid and outstanding. Optionally as of a key date.
List accounting postingscollmex_list_accounting_documents
Accounting postings (record ACCDOC_GET), one row per posting position: posting number, date, text, account, debit/credit (0 debit, 1 credit), amount, customer/vendor, invoice number. Filter by fiscal year, account, cost centre, customer, vendor, invoice or document date range. Cancelled postings are excluded unless asked for.
Get account balancescollmex_get_account_balances
Account balances from the Collmex accounting (record ACCBAL_GET) for a fiscal year: account number, name and balance. Filter by account, account group (1 other, 2 fixed assets, 3 bank/cash, 4 income, 5 expenses, 6 output VAT, 7 input VAT, 8 receivables, 9 payables, 10 depreciation, 11 provisions, 12 inventory, 13 private, 14 non-deductible expenses), cost centre or an up-to date. With a customer or vendor given, the date is ignored.
List projectscollmex_list_projects
Collmex projects (record PROJECT_GET) with customer, budget, value of recorded activities, completion state and the project's rates (rate number, description, product, hourly or daily rate).
List project activitiescollmex_list_activities
Recorded time-tracking activities (record ACTIVITIES_GET): project, employee, date, from/to times, breaks, description, and the invoice that billed it. Filter by project, employee (needs company), date range, only not-yet-billed or only invoice-relevant activities.

Changes data · 2

Create customercollmex_create_customer
WRITE: create a NEW customer in Collmex (record CMXKND without a customer number, so Collmex assigns the next number; an existing customer is never overwritten). Each call creates another customer: check collmex_list_customers first to avoid duplicates. Nothing is sent to the customer. Give at least a company or a last name. Returns the new customer number.
Create address-book entrycollmex_create_address
WRITE: create a NEW entry in the Collmex address book (record CMXADR, address type 3, no address number so Collmex assigns one; existing addresses are never overwritten). Each call creates another entry: check collmex_list_addresses first to avoid duplicates. Nothing is sent to the person. Give at least a company or a last name. Returns the new address number.

Your usefulapi plan · 4

Usage status (free-tier meter)collmex_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 featurecollmex_request_feature
Tell usefulapi that the user needs something the Collmex 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+collmex_upgrade
Get a paid plan for Collmex (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 (needs confirm: true; the price difference for the rest of the period is charged at once). 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 subscriptioncollmex_cancel_subscription
Cancel the caller's Collmex 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 collmex_upgrade later to undo the cancel before the period ends. Does not count against the meter.

FAQ

What can I do with Collmex in Claude or ChatGPT?

Review overdue balances. Check stock before quoting. Review a customer order. Create a customer after checking for duplicates. See what you can do for the details.

Is this an official Collmex product?

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

Can I connect Collmex 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 Collmex customer number, API user name and API user password. See Before you connect for where to find them.

Do I put my Collmex 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 Collmex customer number, API user name and API user 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 Collmex credentials?

The login stores them encrypted in the authorization grant of your connection. The server uses them to call the Collmex 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 Collmex.

Can the AI change my Collmex data?

Yes, if you approve it. 2 of the 15 Collmex tools can create or change data. The other 13 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 Collmex server only. Cancel any time: your paid plan then runs to the end of the paid period. Run collmex_usage_status to see how many calls you used.

How do I subscribe or cancel?

Ask the AI to run collmex_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 collmex_cancel_subscription. Your paid plan continues to the end of the paid period.

What if a Collmex tool that I need is missing?

Tell the AI what you wanted to do. It can send the request with collmex_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.

More Accounting & Tax MCP servers

All Accounting & Tax servers →