Constructor of trading bots

Web platform for crypto traders: marketplace for trading bots and templates, personal account with exchange connections, visual strategy builder, market data, billing, support, blog, and multilingualism.

Role: full-stack development, module architecture design, integration of payment and exchange APIs.

Stack:
Frontend — Next.js (App Router), React, TypeScript, Tailwind CSS, Radix UI, localization EN/UK/RU.
Backend — NestJS, MySQL.
Auth — NextAuth.
Payments — WayForPay (checkout, webhook, history, subscriptions, and marketplace).
Data — SQL schemas/migrations: users, subscriptions, strategies, marketplace, reviews, sales, support, Telegram, AI chats.

Public part:
Main and marketing pages (about the product, FAQ, careers, contacts, docs, policy, cookies, payment).
Blog (categories, lists, posts by slug).
Newsletter subscription via API.
Feedback form.
Full multilingual interface and content.

Marketplace:
Catalog with filters and facet aggregations.
Product card (description, media, rating, similar).
Reviews (view/create, linked to user).
Favorites.
Cart and checkout through payment session.
Payment result pages (success/fail).
Background statistics recalculation (scheduler).

Personal account:
Dashboard with quick actions and access to support.
Strategies: list, creation/editing, configuration, statistics, trades, backtesting, troubleshooting.
Templates: catalog and create strategy from template.
Backtesting — separate testing area.
Exchanges: manage API connections (CRUD, key verification).
Orders: list of purchases and payment statuses.
Billing: subscription, rates, renewal, auto-renewal.
Payments: history and repeat.
Promo codes.
Profile and security (password, sessions, logout).
Notifications.
Support: tickets and correspondence.
Service status page.

Strategy builder (workflow builder):
Graphical editor for nodes and connections (conditions, indicators, IF logic).
Save/load workflow (API).
Publish/unpublish templates.
Strategy balance context.
AI assistant: chat sessions, SSE streaming, applying changes to workflow.

Market data:
API and proxy routes: symbols, tickers, market context.
Indicators: RSI, MACD, Stochastic, Bollinger, ATR, Fibonacci, volumes.
Integration with exchange (including Binance).
Usage in charts and strategy logic.

Telegram:
Account linking.
MTProto authorization (code, password).
Receiving dialogs and live messages.
Notifications about errors/events.

Authentication:
Registration, login, Google OAuth, password recovery.
Profile and session verification.

Billing:
Rates and subscriptions.
Checkout for subscriptions and marketplace.
Webhook WayForPay: verification, status updates, synchronization of sales and subscriptions.
Payment retries, auto-renewal.

Communications:
Support tickets (CRUD, message threads).
Email subscriptions.

Quality:
Strict TypeScript typing.
Global error handling (NestJS).
Unit tests for domain logic workflow (Vitest).