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sergey_kozlov01

Sergey K.

@sergey_kozlov01

Backend developer: Telegram bots, scrapers, automation

Georgia
Russian, English
About me
Hi, I'm Sergey, a backend developer (Node.js / NestJS). I build backend and integrations for a marketing team, including a lead processing service handling ~20,000 leads a day. What I build: - Telegram bots and Mini Apps - Discord and Slack bots - AI agents for lead generation - Web scrapers and PDF / OCR data extraction - Chrome extensions - API integrations I work through Fiverr chat only, no calls. Everything stays in writing, so nothing gets lost. Message me before ordering and I'll tell you honestly if your task is a good fit.... Read more

Skills

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sergey_kozlov01
Sergey K.
Offline • 

See my services

Automations & Agents
I will build API integrations and web scrapers for your business
From$20 / projectMore details
Rule Based Chatbots
I will build a custom telegram bot or mini app with payments
From$25 / projectMore details

Portfolio

Work experience

Backend Developer (Node.js / NestJS)

Performance marketing team • Freelance

Dec 2024 - Present • 1 yr 11 mos

Backend developer for a performance marketing team. I built the team's infrastructure from scratch and own its core services. - Lead processing service: ~20,000 leads a day. Intake from landing forms, queues (Redis / BullMQ), validation, deduplication and routing to partners. - Monetization services: logic that routes traffic to partner offers and the thank-you page offerwall. - Analytics: event storage in ClickHouse, data in MongoDB, conversion tracking for ad counters. - Integrations with partners and ad platforms via REST APIs and webhooks. Stack: Node.js, TypeScript, NestJS, MongoDB, ClickHouse, Redis, BullMQ, Docker.