Integration · Accounting

Connect Claude & ChatGPT to InvoiceXpress

Ask your AI to draft an invoice, check what a client owes or find the PDF of a document in InvoiceXpress. It can create clients, items, quotes, proformas and draft invoices, record payments and list a client's documents. It can also finalize, cancel and email documents, with your approval if you want it.

Connect InvoiceXpress free

Free plan, no credit card. Takes about a minute.

Try asking

“What is the balance for client C-0042?”
The AI finds the client by code and reads their current account balance.
“Create a draft invoice for Café Lisboa: 3 hours of design at 60 EUR with our normal VAT rate.”
It finds the client and your tax rates, then creates a draft invoice with one line. The draft can still be changed.
“Make a quote for Hotel Mar: website maintenance, 12 months at 90 EUR.”
It creates a quote with the client and the item. You can also ask for a proforma or a fees note.

What your AI can do

Invoices and quotes

Create draft invoices, invoice-receipts, simplified invoices, credit and debit notes, quotes, proformas and fees notes.

Clients and items

Find clients by code or name, create clients with NIF and address, read balances, and create and list products and services.

Payments and PDFs

Record payments as receipts, see related documents, get PDF links and email documents to clients.

“Record 450 EUR received today against invoice 1187.”
It records the payment on the invoice, which creates a receipt. No money is moved.
“Get me the PDF of invoice 1187.”
It returns a download link for the document's PDF.
“List all documents for Café Lisboa.”
It lists the client's invoices and other documents, and can filter by status or document type.

45 tools for InvoiceXpress

These tools are switched on when you connect. You can switch any of them off, or require your approval before it runs.

cancel_change_state_jsonMoves moneyCancel a change state json (receipt id). Financial or irreversible action; may require approval. API summary: Cancel Payment.
change_invoice_stateVisible to othersChange a document's state by `invoices_type` and `document_id`: finalized, canceled, deleted, settled and others. Finalizing issues the legal document with a number and cannot be undone. Optional `message`, e.g. a cancellation reason.
create_account_already_user_jsonChanges dataCreate a new account. Required: account. API summary: Create for existing user.
create_account_jsonChanges dataCreate a new account. Required: account. API summary: Create Account.
create_at_communication_jsonChanges dataCreate a new at communication json. Required: at communication.
create_clientChanges dataCreate a client from a `client` object with name and code (required) plus optional email, fiscal_id (NIF), address, postal_code, city, country, phone and language.
create_customer_regularization_jsonChanges dataCreate a new regularization json for a customer. Required: regularization. API summary: Create Regularization.
create_customer_treasury_movements_jsonChanges dataCreate a new treasury movements json for a customer. Required: treasury movement. API summary: Create Treasury Movement.
create_estimateChanges dataCreate a quote, proforma or fees note (`estimates_type`) from a `quote` object with client and items, plus optional date, due_date and observations.
create_guideChanges dataCreate a new invoice. Required: shipping. API summary: Create Guide.
create_invoiceChanges dataCreate a draft invoice, invoice-receipt, simplified invoice, credit note or debit note (`invoices_type`) from an `invoice` object with date, due_date, client (name and code) and items (name, unit price, quantity, tax). It stays a draft until finalized.
create_itemChanges dataCreate a product or service from an `item` object with name, description and unit_price, plus optional unit and tax name.
create_sequences_jsonChanges dataCreate a new sequences json. Required: sequence. API summary: Create Sequence.
create_taxes_jsonChanges dataCreate a new taxes json. Required: tax. API summary: Create Taxes.
delete_invoicesMoves moneyPermanently delete a invoice by taxes id. Financial or irreversible action; may require approval. API summary: Delete Tax.
delete_itemMoves moneyPermanently delete a invoice by invoice id. Financial or irreversible action; may require approval. API summary: Delete Item.
delete_regularizationMoves moneyPermanently delete a invoice by invoice id. Financial or irreversible action; may require approval. API summary: Delete Regularization.
delete_treasury_movementMoves moneyPermanently delete a invoice by invoice id. Financial or irreversible action; may require approval. API summary: Delete Treasury Movement.
email_invoiceDeletesEmail an invoice-type document to the client by `invoices_type` and `document_id`, with a `message` (client email, optional subject, body, cc, bcc). This sends an email.
find_client_by_codeFind a client by their client `client_code`.
find_client_by_nameFind a client by exact `client_name` (partial names are not matched).
get_account_jsonGet one account by account id. API summary: Get Account.
get_clientGet one client's details. Pass the client's ID in `invoice_id`.
get_client_balanceGet the current account balance of a client by `client_id`.
get_estimateGet one quote, proforma or fees note by `estimates_type` and `document_id`.
get_guideList invoices. API summary: Get Guide.
get_invoiceGet one invoice-type document by `invoices_type` and `document_id`, with client, items, totals and status.
get_invoice_pdfGet a PDF download link for a document by `document_id`; set second_copy for a duplicate copy.
get_itemGet one item. Pass the item's ID in `invoice_id`.
get_qr_codeList invoices. API summary: Get QR Code.
get_sequenceList invoices. API summary: Get Sequence.
get_taxesList invoices. API summary: Get Taxes.
list_client_invoicesChanges dataList a client's invoices and other documents by `client_id`, optionally filtered by status, document type or archived.
list_clientsList your clients, page by page.
list_customer_regularization_jsonsList regularization jsons for a customer. API summary: Get Client Regularization.
list_itemsList your products and services (items), page by page.
list_related_documentsList documents linked to a document (receipts, credit notes and so on) by `document_id`.
list_sequences_jsonsList sequences jsons. API summary: List All Sequences.
list_taxesList the VAT/tax rates set up in your account, for use on items and documents.
record_invoice_paymentChanges dataRecord a payment received against an invoice by `document_id`, with `partial_payment` amount and optional payment_date, payment_mechanism and note. Creates a receipt; no money is moved.
update_account_jsonChanges dataUpdate an existing account identified by account id. API summary: Update Account.
update_customer_initial_balance_jsonsVisible to othersUpdate an existing initial balance json identified by client id. Has effects visible outside this system. API summary: Update Initial Balance.
update_invoiceVisible to othersUpdate a draft invoice-type document by `invoices_type` and `document_id` with a full `invoice` object (date, due_date, client, items).
update_sequence_current_jsonChanges dataUpdate an existing sequence identified by sequence id. API summary: Set Sequence as Default.
update_sequence_register_jsonsVisible to othersUpdate an existing register json identified by sequence id. Has effects visible outside this system. API summary: Register Sequence.

Set up in three steps

1
Pick the app
Create a free HeyMyApps account and choose InvoiceXpress from the app list.
2
Paste your key
Enter your InvoiceXpress account name and API key. Log in to InvoiceXpress and open Account > API (www.app.invoicexpress.com/users/api) to see both. The account name is the part before .app.invoicexpress.com, for example acme in acme.app.invoicexpress.com.
3
Add the link to your AI
You get a personal MCP link. Add it to Claude, ChatGPT or Cursor:
1. Click your name, then Settings › Connectors › Add custom connector.
2. Paste your link as the Remote MCP server URL.
3. Switch it on from the + menu in a chat.

Questions

What can the AI do in InvoiceXpress?

The AI can read and find clients, items, tax rates, invoices, estimates, related documents and client balances, and get PDF links. It can create clients, items, estimates and draft invoices, update drafts and record payments. It can also change a document's state and email documents to clients if you switch those tools on.

Does the AI see my InvoiceXpress API key?

No. Your InvoiceXpress credentials are encrypted at rest and never shown to the AI. After you save them, they are not shown again, not even to you. The AI only sees the results of the tools it calls.

Can I control what the AI is allowed to do?

Yes. You choose which tools are switched on, so you can start read-only. Finalizing a document issues it with a number and cannot be undone, and emailing sends it to the client. Both can require your approval before they run. Every tool call is logged.

Does it work with ChatGPT?

Yes. In ChatGPT go to Settings › Apps & Connectors › Advanced and turn on Developer mode, then add your HeyMyApps link. Developer mode needs a paid ChatGPT plan: Plus, Pro, Business or Enterprise. The same link also works in Claude (Settings › Connectors › Add custom connector), Cursor and other MCP clients.

What does it cost?

HeyMyApps has a free plan with no credit card required. Paid plans bill per completed task. You also need your own InvoiceXpress account.

Can the AI finalize invoices?

Only if you switch on change_invoice_state. New invoices are created as drafts. Finalizing issues the legal document with a number and cannot be undone, so it is a good tool to keep behind approval. The same tool can also cancel, delete or settle a document.