Lieben maps 28 APIs for cold email inside Claude Code

Michel Lieben has published the connection map behind running a campaign in Claude Code without opening Apollo or Instantly by hand. He names 28 APIs and, more usefully, the order he would wire them in for a first build. This follows his earlier walkthrough of the same setup.

The order he gives

Context first. Lieben writes down the target, the offer and why those companies would need it, then drops best-performing emails and previous campaign results into a client folder so Claude can judge which accounts are worth contacting. His worked example is selling phone data to companies hiring cold callers.

The list gets built around that signal. TheirStack or PredictLeads find the hiring activity, and he asks Claude to read the job descriptions and keep the evidence beside each company. Apollo or Prospeo find the sales leaders. AI Ark's lookalike search is the route if you are starting from existing customers, Exa for companies the databases cover badly.

Then addresses. FullEnrich runs a waterfall across providers, or you connect Findymail, LeadMagic or Prospeo individually and set their order so the chain stops once there is a verified address. He keeps the provider and verification status in the export and holds catch-all and unknown addresses out of the campaign entirely.

Everything lands in a Supabase leads table holding contact, buying signal, source, verification status and campaign together. Sumble adds team and initiative research on accounts worth it, RB2B adds identified US website visitors that he qualifies against ICP before anyone writes to them.

Sending is the last step, not the first. Hypertide for domains and inboxes, Instantly for sequencing, lemlist for multichannel, Expandi for LinkedIn. Claude creates the campaign and uploads the verified contacts, but leaves it inactive while the copy, merge fields and sending settings get checked by a human. The campaign ID goes back into the leads table so replies can be traced to the original targeting.

After a reply, Zapier pushes the event into folk and notifies whoever owns it, and Claap captures the calls so real objections and buyer language come back into the campaign context. Where a step has no API, he suggests testing Airtop on the browser task before trusting it.

For people sending, this replaces the Clay table, not the inboxes or the verification bill, so the saving is hours rather than stack cost. Lieben's own caution is the part worth keeping regardless of tooling, that a matching job title does not tell you whether the company needs your product.

Michel Lieben

@MichLieben

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