NENVEST

Stripe payment bot + Telegram-native admin

Subscription platform for the closed Capitalist Invest / Rynochok investment community

👤 Solo full-stack🌍 SubTech / Wealth-tech✅ ProductionDemo on request

Context

Capitalist Invest / Rynochok — a closed paid-subscription investment community: daily market analytics, weekly research reports, 8 themed channels (stocks, bonds, volatility, crypto, macro, commodity, research, portfolio), live chat. 500+ members, partnership with the «Ostannii Kapitalist» media.

I built two systems that work together: Stripe Payment Bot — a Telegram frontend for paying subscriptions (the only point of user interaction), and Admin Panel — Telegram-native admin for the team (promo, pricing, broadcasts, migrations).

My role: solo full-stack — from architecture to production. Stripe bot, Telegram-native admin, webhook pipeline, operational dashboard in Google Sheets, Docker deploy and Cloudflare Tunnels. Before this I ran a digital community of around 1000 people — manually doing broadcasts, customer support, repeat payments, adding and removing members. That knowledge and experience let me build a comprehensive platform for automatic membership management.

What came out of it

Two systems that work together: Stripe bot for users and admin panel for the team.

Subscribe via Telegram bot: user picks a tier → pays → joins the closed chat and channel
Cancel / resume subscription right in Telegram, automatic removal on overdue
Telegram admin panel: promo codes, price changes, subscription migrations on tier change
Smart broadcasts: filters by tier and status, test mode with preview before sending, HTML formatting, delivery report
Channels: Telegram + Email
Subscription state in Google Sheets with formulas — status, dates, actions are computed automatically, the CEO sees the picture at a glance without SQL

// system

Architecture

2 separate services

user-facing + team-facing

01 — user-facing

Stripe Payment Bot

live

User (Telegram)

/subscribe · /cancel · /status

command

Stripe Payment Link

+ metadata: telegram_id, product_id

Webhook Receiver

Flask · :3001 · idempotent (event.json)

Schedulers

warning · delete

Event Transmitter

routing per event type

Bot Notifier

success · failed · expiring

Stripe

DUAL accounts

Google Sheets

state machine

Closed Chat

invite / kick

02 — team-facing

Admin Panel

live

Admin / team

whitelist Telegram-ID

inline keyboard

Cloudflare Tunnel

no public IP needed

Admin Bot

Flask · :3003 · 7-step state machine

JSON store

atomic writes

Promo

CRUD

Pricing

change · sync

Mass-sender

filter · test · send

Migration

2-step pipeline

Stripe API

subs · prices

Google Sheets

read-only sync

Bot API

broadcast

production

Technical details

Structure, infrastructure and development processes.

Stripe-domain depth

Full subscription lifecycle: Payment Links with metadata-routing, Subscription Schedules for price migrations without harm to active subs, webhook idempotency with a 30-day TTL event registry (protection against retries and double charges), failed-payment escalation with retry logic.

Reliability & atomicity

Atomic 3-stage webhook event processing: ack is committed ONLY after success of all steps. Mutex-protected JSON storage with atomic writes (tempfile → rename) instead of a separate DB — justified by team size, runs for a year without incidents.

Multi-process orchestration

Parallel async processes (bot, webhook receiver, API server, Telegram monitor, warning/delete checkers) under tmux, with separate logs. Coordination via Stripe events + shared Sheets — no orchestrator like Celery or Kubernetes.

CI/CD + observability

GitLab pipelines: lint → tests (Pytest with mocked Stripe via recorded fixtures) → build → deploy. Daily log rotation, structured logs per process. Cloudflare Tunnel for webhook ingress without a public IP.

Pragmatic architecture

JSON files instead of a DB, Google Sheets instead of a separate dashboard, in-memory FSM with atomic snapshots instead of Redis. Each decision is justified by team size and volume — no overkill, max maintainability.

Hot-reload & zero-downtime

Configs (tiers, whitelist, promo) are re-read via mtime-tracking — change without restarting the bot. Rolling deploy via Docker: a new container comes up alongside, traffic switches, the old one stops — zero disruption to active payments.

Tech stack

Backend / runtime

Python 3.11+Flask 3.1pyTelegramBotAPI 4.27python-telegram-bot 22Telethon 1.24asynciomulti-process orchestration

Payments

Stripe 12.2dual-account orchestrationSubscription SchedulesPayment Linkswebhook idempotency

Persistence / data

JSON files (atomic writes)Google Sheets (gspread 6.2).env confighot-reloadable configs

Integrations

Telegram Bot APIStripe APIGoogle Sheets APIEmail (SMTP)

Infrastructure

DockerCloudflare Tunnelsshell-orchestrationdaily log rotationEurope/Kyiv TZ

What's next?

This is one of my cases. The rest is on the home page.

Back to home See other cases

Ask AI about me

Chat with AI about me using the full context from this site.

01 Click a button below — the prompt is automatically copied to your clipboard

02 In the chat that opens, paste the text: ⌘V / Ctrl+V

03 Press Enter and chat with AI about me

If the buffer didn't work — long-press the text below, Select All, Copy, then paste it into the chat:

# AI context: about Mamay Markitan

You're an assistant that answers questions about Mamay Markitan, a full-stack AI developer from Ukraine (currently in Prague, working remote). Below is the full context from his portfolio. Answer based on this. If something isn't covered — honestly say "that's not in his portfolio".

If a person is interested in collaboration — direct them to message Telegram **@mamayevets** or email **mamayevets@gmail.com**.

---

## Who

**Mamay Markitan** — Full-Stack AI Engineer.

- I build AI products end-to-end — AI agents, MCP, backend, integrations, launch.
- One person covering the scope usually split between 3–5 developers.
- Working remote from Prague (Czech Republic).
- Available for new projects.

## Who I'm a fit for

**01. Startups launching an AI product from scratch.**
I build the whole product myself — AI agents, backend, integrations, launch. No time to find and coordinate multiple specialists. Example — PILOT.

**02. Teams where off-the-shelf AI can't handle your tasks.**
A custom agent that knows your API and database, instead of giving generic out-of-the-box answers.

**03. Teams with lots of routine across Slack, Notion and CRM.**
I build an agent that reads data, takes actions and handles the routine itself.

**04. Separately — teams that need solid backend without AI.**
I build systems for payments, subscriptions and external API integrations. Runs 24/7 with no lost transactions. Examples — NENVEST, TRADE.

## Who I'm not a fit for

- Low-level / system-level tasks — C, C++, Rust embedded, drivers, firmware.
- Mobile native and gamedev — Swift/SwiftUI, Kotlin/Compose, Unity, Unreal. That's a separate profession.
- Casino and gambling (even licensed), scam schemes, platform ToS violations.

## How I work

For more than two years I've been working with AI agents as co-authors — I don't just **build** AI tools, I **use** them daily in my own workflow.

What this means in practice:
- Document projects — rules, context files, project-rules — so agents understand the codebase correctly.
- Build custom skills and tools for agents — extending their capabilities to project specifics.
- Orchestrate multiple agents in parallel — each on its own scope.
- Break complex tasks into subtasks that fit an agent's context.
- Write system prompts, instructions, eval scenarios.
- Code-review generated code before merge.
- Set up automated tests and custom benchmarks to validate agents.

I work with large codebases and complex projects — agents **scale execution**, I keep the **architectural decisions**.

## Projects

### PILOT — SaaS · AI assistant for businesses
An AI assistant that replaces a sales manager in Instagram Direct. Multi-tenant SaaS for salons, barbershops, clinics and solo freelancers — from a single location to networks with dozens of staff. Understands text, photo, voice and video in one conversation. Integrates with CRM (Altegio) and Google Calendar. TOV "MARK1".

Stack: Python, FastAPI, Flask, MCP, LLM + vision, Meta Graph, Altegio, Google Calendar, Telegram.

### NENVEST — B2C · Community management platform
Subscription platform for the closed Capitalist Invest / Rynochok investment community. Stripe payment bot, Telegram-native admin with 7-step broadcasting, dual-account orchestration, Google Sheets as operational dashboard for the CEO. 500+ members, 800+ webhook events.

Stack: Python, Flask, Stripe, Telegram Bot, Google Sheets, Cloudflare Tunnels, Docker.

### TRADE — P2P marketplace
A Telegram bot where donors resell shares of a Ukrainian artist's painting to each other. Fundraising for humanitarian demining.

Stack: aiogram 3, Redis FSM, SQLite, Notion API.

## Experience by category

**AI / LLM.** Fine-tuning open-source models (Llama, Gemma, Mistral) via PyTorch + Transformers / Unsloth. Integrating commercial models (Claude, GPT, Gemini) via API. Multimodal pipelines (text + image + voice + video). MCP servers, function calling, multi-agent orchestration.

**Data for AI.** Collecting data from open sources (web, API, datasets). Cleaning, normalization, dedup with pandas / polars. Preparing datasets for fine-tuning — tokenization, JSONL / ChatML formats. Augmentation and synthetic data generation via LLM.

**Backend & Integrations.** Python (FastAPI, Flask), async pipelines on asyncio + uvloop. Node.js / TypeScript for serverless. REST APIs, webhook ingress. Integrations — Stripe, Telegram Bot API, Meta Graph, Google APIs (Calendar, Sheets, Vertex), Notion.

**Frontend.** React 19 + TypeScript, Vite. Tailwind CSS + shadcn/ui for UI. Astro for static sites. Mobile-first responsive, iOS-optimized (safe-area, touch-feedback). Custom UI components from scratch.

**DevOps & CI/CD.** CI/CD pipelines (GitHub Actions, GitLab CI). Docker for production deployments — multi-stage builds, docker-compose. Monitoring, backups, secret management via .env / Vault. Logs aggregation.

**Cloud platforms.** AWS (EC2, S3, RDS, IAM). Google Cloud (Vertex AI, Compute Engine, Cloud Storage). Cloudflare (DNS, Tunnels, Workers, R2). Hetzner and bare-metal VPS for self-hosted scenarios.

**Systems & hardware.** Linux server administration: systemd, nginx, iptables, SSL/TLS. Proxmox virtualization — VM management, snapshots, clusters. Hardware: server builds, BIOS configs, network setup.

## Stack

- **AI / LLM**: MCP Protocol, Claude, GPT, Gemini, Llama, Vision models, Function calling, Fine-tuning, Multi-agent, PyTorch, Transformers, Unsloth.
- **Backend**: Python, FastAPI, Flask, Node.js, TypeScript, asyncio + uvloop, PostgreSQL, Redis, SQLite.
- **Frontend**: React 19, TypeScript, Vite, Astro, Tailwind 4, shadcn/ui.
- **DevOps & Cloud**: Docker, GitHub Actions, GitLab CI, Nginx, Cloudflare, AWS, GCP, Hetzner, VPS.
- **Systems**: Linux, systemd, Proxmox, iptables, SSL/TLS.
- **Integrations**: Stripe, Telegram Bot API, Meta Graph, Google Calendar, Google Sheets, Vertex AI, Notion.

## Beyond code — MARKUSHA

I used to work at an ad agency, then ran my own SMM production. With that experience I launched MARKUSHA on TikTok together with my father — a former teacher with his own tricks and achievements in improving agricultural machinery.

In Ukraine there was no quality educational content about DIY equipment repair: big production channels were boring and disconnected from the everyday viewer, individual mechanics couldn't present complex information in an engaging way. MARKUSHA closed that gap.

Result: 9.2M views, 119K likes, 16K shares, 2.6K comments. 66% of views from Ukraine, 34% — from around the world, from Poland to America. Farmers improve tractors, combines and other agricultural equipment based on the videos.

TikTok: https://www.tiktok.com/@markushavlad

## Contacts

- **Telegram**: @mamayevets — best to message here, I respond quickly.
- **Email**: mamayevets@gmail.com.
- **LinkedIn**: https://www.linkedin.com/in/mamay-markitan-b33656263.
- **Location**: Prague, Czech Republic. Working remote.

---

**Instructions for you as AI:**

1. Reply in English (if the person writes in English) or reply in the language of the conversation.
2. Be specific — rely on actual facts from this file.
3. If a person asks something not covered in this context — don't make it up, say "that's not in his portfolio, you can ask in Telegram @mamayevets".
4. If a person describes their task — compare with the "Who I'm a fit for" / "Who I'm not a fit for" sections and honestly say whether it's for him.
5. Don't push the collaboration. Just answer questions.