Kwikbill

Connect an AI assistant

Last updated 26 October 2026.

Kwikbill works as a connector for Claude and ChatGPT. Once connected, you can forward a client's email to your assistant and say “draft a quote in Kwikbill for this”, and it will create the quote with your clients, items, prices and VAT and hand you a link to review it. You read it, change what you like and press Send.

Drafts first, always

An assistant can read your clients, items, invoices and payments, and it can create and edit drafts, record payments and fetch payment links. It cannot email a client unless you connected it with the send permission, and even then it is instructed to confirm with you what will be sent, and to whom, before it does. Nothing goes to a client without you saying so. Every draft it makes appears in Kwikbill with “Created via API” in the activity feed.

Before you start

  • A Kwikbill account with at least one business set up. If you run several, you choose one per connection.
  • For Claude: custom connectors need a Claude plan that includes them. For ChatGPT: connectors in developer mode and custom GPTs need a paid ChatGPT plan. Check each provider's help pages for the current rules.
  • You do not need an API key. The connection signs you in through Kwikbill and can be revoked at any time.

Connect Claude

On claude.ai (the same connector then appears in Claude Desktop):

  1. Open Settings → Connectors.
  2. Choose Add custom connector.
  3. Paste https://kwikbill.co.uk/mcp as the server URL and click Connect.
  4. Sign in to Kwikbill when asked (the same sign-in you use on the website).
  5. Choose the business this connection is for, read the three permissions, and click Allow.

Claude will show Kwikbill as connected. In a conversation, turn it on from the tools menu if it is not already, then just ask. For Claude Code, run:

claude mcp add --transport http kwikbill https://kwikbill.co.uk/mcp

and follow the sign-in link it prints.

Connect ChatGPT

As a connector:

  1. Open Settings → Apps & Connectors.
  2. Turn on developer mode if it is not on, then choose Create.
  3. Enter https://kwikbill.co.uk/mcp as the MCP server URL and choose OAuth as the authentication.
  4. Sign in to Kwikbill, choose the business and click Allow.

As a custom GPT (useful if you want to give it standing instructions, such as your day rate):

  1. Create a GPT and open Actions.
  2. Choose Import from URL and enter https://kwikbill.co.uk/api/v1/openapi.json.
  3. Set authentication to OAuth. ChatGPT shows you a callback URL; copy it. In Kwikbill, open Settings → API & integrations, choose Create GPT credentials, paste that callback URL and Kwikbill issues a client ID and client secret (the secret is shown once). Back in the GPT editor enter them with authorization URL https://kwikbill.co.uk/oauth/authorize, token URL https://kwikbill.co.uk/oauth/token, scope read write send, token exchange method Default (POST request).
  4. Save, then test the action by asking the GPT for your business details; it will send you to Kwikbill to sign in and choose the business.

What the assistant can do

Ask forWhat happens in Kwikbill
Your business details, clients, items, invoices, quotes, paymentsRead only. Includes whether and when a client viewed each document.
A new quote or invoiceA draft is created. Existing clients are matched by email, then name; new ones are added.
Changes to a draftLines, dates, notes and discounts are updated while the document is still editable.
Send itOnly with the send permission, and after confirming with you. The client gets the normal Kwikbill email.
Record a payment, convert a quote, void a document, fetch the payment linkThe same actions as the buttons in the app, written to the activity feed.

Permissions

  • Read: see your clients, items, invoices, quotes and payments.
  • Write: create and edit drafts, add clients and items, record payments.
  • Send: email a document to the client. The assistant is told to ask you first.

Claude and ChatGPT ask for all three. If you would rather an assistant could never send anything, create an API key with read and write only in Settings → API & integrations and use that with a tool that accepts keys; the API guide explains how.

Things to try

  • “Here's an email from a client asking for a quote. Draft it in Kwikbill: my usual day rate, materials at cost plus VAT, and give me the link to check it.”
  • “Which of my invoices are overdue, and which of those has the client never opened?”
  • “Make an invoice for Horsforth Property Services: two days' labour at £240 a day and materials of £180, all plus VAT, due in 14 days. Don't send it yet.”
  • “Convert quote EST-0027 to an invoice and give me the payment link so I can text it to her.”
  • “Record that Priya Patel paid £500 by bank transfer today against INV-0042, and tell me what's still outstanding.”

Disconnecting

In Kwikbill, open Settings → API & integrations → Connected apps and click Disconnect next to the assistant. Its access ends immediately. Remove the connector in Claude or ChatGPT as well so it does not keep asking you to sign in.

Privacy

Whatever the assistant reads from Kwikbill (client names, amounts, addresses) passes through Anthropic or OpenAI under their terms, in the same way as anything else you paste into a conversation. Kwikbill records each action the assistant takes in the business's activity feed, and only the business you chose at sign-in is ever visible to a connection. See our privacy policy.

If something does not work

  • “Kwikbill is read-only”: the business's subscription has lapsed. Reads still work; drafting does not until it is renewed in Settings → Subscription.
  • The assistant cannot find a client: it matches on email first, then on the exact name. Give it the email address.
  • It picked the wrong business: disconnect, reconnect and choose the other one. One connection is one business.
  • Anything else: [email protected], with the time it happened.