Prospectingthat stays yours.

Coldlyne is an MCP (Model Context Protocol) server, the open standard that lets an assistant use tools. You add it as a connector in Claude (on the web, in the app or in Claude Code) or in ChatGPT, with your workspace’s address, and you sign in. Your assistant searches, writes, schedules and reads replies; the Coldlyne app shows everything it has done and lets you take over any of it by hand.

Yes, on every channel that goes through an API: email from your mailbox, SMS, postal mail, and WhatsApp with people who have agreed to be contacted there. You can also ask it to have you approve everything first, in the conversation or in the app. Some rules aren’t negotiable: sending caps, sending hours, the suppression list, the legal notices.

No, and that’s deliberate. Their terms forbid automatically writing to people who haven’t asked you for anything, and a suspended account can no longer prospect. Coldlyne finds the person, writes the message and puts it in your list for the day: one click opens the conversation with the text ready, you send it from your account, and the sequence carries on. On WhatsApp, the first message goes out from your account in the same way; what follows goes through the official WhatsApp Business API, with people who have agreed to be contacted there.

Each planned call lands in your list for the day with the number, a script prepared from public facts and room for your notes. You call from the app, through the phone provider you connect. If you reach voicemail, one click leaves the message recorded for the campaign. You note the outcome (voicemail, call back, meeting, not interested) and the sequence follows: a callback is scheduled, or everything stops.

They go out on their own. SMS goes through the provider you connect, on weekdays and during business hours; each one says who is writing and ends with STOP. Letters go through an online mailing service that prints and posts them to the head office address given by the registry; each one says who is writing, where the address comes from and how to object. An objection on any channel applies to all of them.

In France, between professionals, yes, if the message concerns their business. The CNIL, the French data protection authority, asks that every message say who is writing, why and where the data comes from, and offer a simple way to object: Coldlyne adds this to every email and letter, every SMS names its sender and ends with STOP, and one exclusion list covers all channels, so anyone who has objected comes out of your sequences. Voicemails are only left during a call you place: an automatic drop would need the person’s prior consent.

From the companies themselves: the national registry for the company, its directors and its head office address, its website (legal notice, contact page) for the email address and phone numbers, public profiles for LinkedIn, Instagram, Facebook or X. Every contact detail keeps its source, and Coldlyne buys none of them.

Yes. The code is free, under the AGPL-3.0 license, and installs on Vercel with a Neon database. Your prospects, your accounts and your sequences then stay entirely with you.