All work

Case study 04 · SMM AI Assistant · AI content-planning SaaS

Five weeks to production.
Billing that adds up.

SMM AI Assistant is our own SaaS for small businesses and social-media specialists: it researches a brand, writes a social-media strategy and prepares a weekly content plan with posts, images and storyboards. Dmytro built it alone and took it to production with billing in five weeks.

Product
AI content-planning SaaS — our own product
Our role
Founder and sole engineer (Dmytro): architecture, development, DevOps, design, QA and product
Period
4 August 2026 → today; in production since 8 September
Users
Solo entrepreneurs and social-media freelancers; dozens at launch
5 weeks

from first commit to production with billing

1

engineer, from architecture to design and QA

margin over AI costs built into pricing

112

automated end-to-end tests

The challenge

Every AI call costs real money. The product had to meter each one, charge users fairly, never pay twice for the same call and keep a margin on every plan — from the first release.

Results

  • In production on 8 September 2026, five weeks after the first commit, with payments, ads and attribution connected.
  • Charges are checked against the OpenAI bill every day; on its first morning the check caught a 3.8% discrepancy.
  • Dozens of users at launch; advertising is still ahead.

What we did

  1. 01

    Strategy first, then weekly content

    Research and strategy come first, then a weekly plan of posts, images and storyboards, generated in the background.

  2. 02

    Billing that protects the margin

    Credits, five Stripe plans and limits per plan, with prices set at three times the AI cost.

  3. 03

    Ready for real users

    An onboarding questionnaire, a calendar of posts and storyboards, strategy import from PDF or CSV, and Ukrainian and English interfaces.

  4. 04

    Growth tools from day one

    An admin panel with a Telegram support bot, consent-based marketing attribution and short links.

  5. 05

    Tested end to end

    112 automated end-to-end tests run against the real database and background worker.

Under the hood

Money that reconciles itself

What users are charged and what OpenAI bills have to match automatically.

  1. Every call is metered in credits, based on the tokens it used and the models the user's plan allows.
  2. A daily job compares charges with the OpenAI bill and raises an alert when they differ by more than 2%.
  3. Background jobs run on queues in Postgres, so a deploy never leaves work stuck or pays for the same call twice.

How we worked

Our own product. Every change goes through a pull request with AI review, the author's own review and automated checks, and the main branch deploys automatically.

Stack

Frontend
  • Next.js 16
  • React 19
  • TypeScript
  • Tailwind v4
  • shadcn/ui
  • Radix
Backend & AI
  • NestJS 11 worker
  • OpenAI API
  • Stripe
  • Telegram Bot API
Data
  • Supabase
  • Postgres
  • RLS
  • Realtime
  • Storage
Delivery
  • Nx 23
  • GitHub Actions
  • Vercel
  • Render
  • Playwright

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