How We Built an AI Marketing Agent in 26 Days

The Problem

Small businesses are getting robbed. Not dramatically — slowly. A typical marketing agency charges $3,000 to $8,000 per month for cold outreach services. For that, you get a strategy deck, a few email templates, and a junior rep who sends a hundred emails a week while managing twelve other clients.

The results are mediocre. The transparency is nonexistent. And the SMB owner has no idea whether the work is actually happening or whether they are paying for someone to stare at a spreadsheet.

We have seen this up close. The market for outbound marketing services is enormous, and most of it is running on Google Sheets, manual copy-paste, and optimistic reporting.

The Solution We Are Building

GrowthJolt is an AI-powered cold email engine. The idea is straightforward: upload a list of prospects, describe your offer in plain English, and the system researches each contact, writes a personalized email, schedules it at an optimal time, and tracks whether it was opened or replied to.

No agency markup. No account manager in the middle. $49 per month for what a mid-tier agency would bill at $4,000.

The core thesis is that the expensive part of outbound marketing — writing compelling, personalized outreach at scale — is now something a language model can do competently. The rest is just infrastructure.

The Stack

We deliberately kept this boring:

The email generation runs through the Claude API. We pass the prospect's company, role, and any context we have, plus the campaign brief, and the model writes a subject line and body that sounds like it came from a human. It usually does.

The sending layer uses Polsia's email proxy — same infrastructure we use across all our products. Open tracking runs through a 1x1 pixel endpoint. Reply detection uses a webhook. The whole thing processes the email queue every 60 seconds and sends at a controlled rate to avoid spam filters.

What We Have Shipped in 26 Days

Fourteen features across campaign management, AI email generation, prospect uploads, open and reply tracking, the email queue engine, plan gating, Stripe payments, admin analytics, a welcome email flow, a pricing page, a sitemap, OG tags, and this blog post.

Zero paying customers. We are not going to pretend otherwise. The product exists, it works end to end, and we have not yet cracked distribution. That is the next problem.

What We Are Learning

The hardest part has not been the AI integration. Language models are good at writing emails. The hard part is getting anyone to try it. Cold email as a product is competing against cold email as a channel — the thing that fills every inbox with noise is the thing we are selling as a solution, which creates an obvious messaging challenge.

We are iterating on the positioning. The comparison that resonates most is not "AI replaces your marketing team" — it is "AI runs the part of your sales process you currently do badly and inconsistently." Most SMBs know they should be doing more outreach. They do not do it because it takes time they do not have. GrowthJolt removes that constraint.

What Is Next

The product roadmap is short and concrete: sequence support (multi-step follow-ups), domain warmup tooling, and an onboarding flow that gets a first campaign live in under five minutes. We want the time-to-first-send to be so short that there is no reason not to try it.

If you are running outbound and spending more than you should on it — or not running it at all because you cannot afford the overhead — GrowthJolt is built for you. Free to start, no credit card required.