Maël H.

Co-founding and developing from scratch an eSIM marketplace in Telegram Mini App - in production with 3400+ plans in 190+ countries, integrated with Airalo as a telecom partner.

Developing a complete crypto payment system from scratch (no existing gems): TON and USDT (Jetton) payments with TonConnect wallet integration, real-time exchange rates, transaction hash verification, overpayment management. 6 payment methods in total: Telegram Stars, TON, USDT, bank cards (Wata for Russia), and internal balance system with bonus/cash split.

Provider abstraction architecture allowing easy switching of eSIM providers. Complete Airalo API integration with mapping of 22 error codes, token rotation, and retry with exponential backoff.

Real-time order tracking via ActionCable with 11+ payment statuses and 5 fulfillment states. Immutable ledger for complete financial audit, dual-balance system with pessimistic locking against race conditions.

Stack: Rails 8, Hotwire/Turbo/Stimulus, TailwindCSS v4, SolidQueue, PostgreSQL (multi-database), deployed with Kamal on Hetzner VPS.

Key achievements: custom crypto processing without dependencies, production-ready in 1 month, internationalization (EN/RU with automated translation sync via Gemini), future iOS architecture already in place.

Creation and development from scratch of a multimodal conversational AI platform on Telegram - 490K+ users, 1000+ DAU, 30+ AI characters with distinct personalities, voices, and visual identities.

Architecture of a multi-stage AI response pipeline processing 2K+ messages/day. Each message triggers 3 concurrent LLM calls (emotion detection, intent classification, conversation analysis), then dynamically routes to the optimal response strategy - text, voice (ElevenLabs v3 with emotions), or images generated with custom LoRA models per character. Integration of 8+ LLM providers (OpenAI, Anthropic, Groq, Cerebras, Grok, DeepSeek) with automatic failover, 2-5s end-to-end latency. Semantic photo matching system reducing generation costs by 25-40%.

Creation of a complete "character factory": AI-generated personality cards, automatic reference image generation, LoRA training pipelines (FAL.ai), voice design (ElevenLabs), dynamic mood overlays - with parallel job orchestration. Characters automatically publish content (Instagram/Fanvue style).

Stack: Rails 7, Telegram Bot API + Mini App (Hotwire/Stimulus/TailwindCSS), SolidQueue, SolidCache, PostgreSQL, Cloudflare R2 - self-hosted on Hetzner VPS, deployed with Kamal. Multi-processor payment abstraction layer (Stripe, Mollie, Telegram Stars) with under-pressure migration after provider changes.

Massive campaign system (150K+ messages) with atomic counters, intelligent fallback routing, and automatic recovery.

Beyond code, complete ownership of product strategy: optimized onboarding (A/B tested from 22 to 8 steps), 4-phase reactivation campaigns (behavioral psychology, emotional callbacks based on memory, scarcity, reciprocity), pricing experiments, abandoned cart recovery, advertising attribution system - tracked across 41 funnel events.

Creation of a WhatsApp SAAS: a bot integrating the most well-known AIs:

- chat: ChatGPT (OpenAI), Bard (Google)

- image generation: StableDiffusion, Dall·e

- speech-to-text: Whisper

- text-to-speech: Google Speech (WaveNet), ElevenLabs

📱 Ciel bot users can:

- talk to AIs, via text or voice message

- read or listen (AI voice) to responses

- generate images from their words, their voice

- generate images from their photos (a selfie, a drawing photo, ...)

- upscale images or photos (2048 px resolution)

- transcribe .mp3 music files, ...

⚡️ And productivity-oriented:

- forward a message to Ciel = Ciel automatically translates it to English

- forward a voice message to Ciel = Ciel automatically transcribes it (to be able to read it, see WhisperBot below!)

...

💻 Ciel in a few steps

- Creation + Setup of WhatsApp Business account

- Automation and integration of AIs into the Ciel bot

- deployment + server configuration (fly.io)

- integration of card payments (Stripe) and Crypto (Cryptomus)

- creation of marketing & pricing

✨ Creation of two gems for this project:

- stability_ai: - replicate-ruby: