Agencies · Freelancers · WhatsApp · Email · SMS
One integration,
every client's own number.
Your client scans a QR code once. From then on, your n8n workflows, your code or Claude send WhatsApp, email and SMS from their number and their mailbox, with no Meta Business verification and no per-message bill to pass on.
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Claude
ChatGPT
Le Chat
GeminiAn agency's month
Twelve clients, twelve WhatsApp setups to babysit
Unlimited Messaging is a messaging API that lets an agency or a freelancer send WhatsApp, email and SMS on behalf of each client, from that client's own WhatsApp number, mailbox and phone, through one REST API, one n8n node and one MCP server.
A dentist wants lead forms answered on WhatsApp. A shop wants order updates. A coach wants a reminder before every call. With the official WhatsApp Cloud API, each of them means a Meta Business portfolio, an Embedded Signup flow, approved templates and a card on file, because Meta bills every delivered template message since July 1, 2025. The setup often takes longer than the automation.
With Unlimited Messaging, the client links their existing WhatsApp by scanning a QR code, like WhatsApp Web, and their mailbox over IMAP/SMTP. You build once: the same API call or n8n node serves every client, you only change the account it sends from. Replies come back in the app, or to your webhook on paid plans.
Same building blocks for freelancers who let Claude reply and for e-commerce order updates. The channel is explained on the WhatsApp page.
What changes
What Unlimited Messaging changes for an agency
Less onboarding per client, one integration to maintain, and a price that does not grow with each message your clients send.
No Meta onboarding per client
No Business verification, no template approval, no Embedded Signup. The client scans a QR code from WhatsApp on their phone, in person or over a video call, and the number is live.
One integration, every account
Every account gets an id. Your workflow passes the client's accountId and the same POST /message sends WhatsApp, email or SMS, or all three in one request.
Your tools: n8n, SDKs, MCP
Use the official n8n node, the TypeScript or Python SDK, or the hosted MCP server so Claude or ChatGPT can draft and send for a client after approval.
A flat price, not a meter
Messages are unlimited on every plan, so a busy client does not raise your bill. The free plan adds a short footer; Medium at €19/month removes it and adds webhooks and media.
Setup
Your first client live in 3 steps
- 01
Create one account
Free sign-up, no credit card. Generate an API key, or connect n8n or your AI assistant.
- 02
Link the client's channels
The client scans the WhatsApp QR code from their phone. Add their mailbox over IMAP/SMTP, and their Android phone through the free app if they want SMS.
- 03
Reuse your workflow
Duplicate your n8n workflow or call the API with the client's accountId. Point replies to the client's CRM through a webhook on a paid plan.
Copy-ready messages
5 messages agencies automate for clients
Replace what is in brackets. Each one leaves from the client's own number or address, so customers recognise the business, not your agency.
- 01 · WhatsApp
Instant reply to a web form lead
Hi [First name], thanks for your request on [website]. I'm [Name] from [Business]. Could you tell me a bit more about [need]? A good time to call you back?
- 02 · WhatsApp
Appointment confirmation
Hi [First name], your appointment at [Business] is confirmed for [day] at [time], [address]. Need to change it? Just reply here.
- 03 · Email
Quote follow-up after 3 days
Hello [First name], I'm following up on the quote sent on [date] for [service]. Do you have any questions, or would you like to adjust something? Best regards, [Name], [Business]
- 04 · SMS
Review request after a visit
Thanks for visiting [Business] today, [First name]. If you have 30 seconds, a review helps us a lot: [link]. [Business]
- 05 · Email
Note to the client before linking
Hi [Client name], To connect your WhatsApp, open WhatsApp on your phone, go to Linked devices and scan the QR code I'll share on our call. Your number stays yours and keeps working on your phone as usual. [Your name], [Agency]
Good to know
When this fits, and when it does not
Customers who know the business
WhatsApp is linked as a device, not through Meta's official API. Messages to leads and customers who wrote first are fine; cold bulk campaigns get a number banned, whatever the tool.
Large broadcasts belong to the Cloud API
A client sending promotions to tens of thousands of opted-in contacts, or who needs a green verified badge, should use Meta's official Cloud API with approved templates.
Free plan for testing
Free messages carry a "Sent with UnlimitedMessaging.app" footer, and media and webhooks are paid-only. For client work, plan on Medium or Max.
FAQ
Questions agencies ask
Sources
Sources & references
To check the information in this article for yourself:
Written by
Ilian · Senior Software Engineer
A senior software engineer, he founds and runs several tech companies. He builds products around messaging APIs, automation and AI integration, and shares here what he learns while building.
Wire up your first client this afternoon
Free, no credit card. One QR code scan and your workflow sends from their number.