A senior engineerfor your next sprint.
MVPs, AI features and payment flows, built by an engineer who has shipped at fintech scale and at a YC startup. EU-based, working in English, invoicing in euro.
Why trust us with your product
Tide
Scaled invoicing to 100k+ users and designed profit-and-loss reporting APIs for 1M+ users. Engineer MVP award within seven months.
Mandel AI
Founding engineer at a YC S23 startup. Built AI agents and data-extraction workflows on LLMs, with tracing and observability from day one.
Own products
ExploreYC reached #1 Product of the Day on Product Hunt. YC Hedge Fund, with 100+ live data feeds and five algorithms, was built in two days using an AI-agent workflow.
Today Konstantin is also a senior engineer on the trading orchestrator at BVNK, a stablecoin payments infrastructure company.
Ways to work together
MVP sprint
From idea to a production-ready first version: accounts, core flows, payments, admin and deployment.
fixed price from €4,000
AI feature sprint
Agents, RAG over your data, document extraction, evals and tracing, shipped inside your product.
fixed scope, quoted in 48 hours
Fractional senior engineer
Senior hands inside your team for architecture, reviews and the hard features nobody has time for.
from €500 / day
Payments and billing
Checkout, subscriptions, invoicing and marketplace payouts, built by someone who has run them at scale.
quoted per scope
Easy to work with from anywhere in Europe
Stack
TypeScript, React and Next.js, Node.js, Java and Spring Boot, Python, PostgreSQL and Supabase, Stripe, LLM APIs, RAG and agents, Vercel and Cloudflare.
- EU company
- Contracts and invoices from a Bulgarian company, in euro.
- Time zone
- Sofia is UTC+2, so the whole European working day overlaps.
- English
- Calls, specs and code reviews in fluent English.
- GDPR
- Data protection considered from the first commit, with EU hosting when you need it.
Before you ask
How do we start?
With a 30-minute call about the outcome you need. Within 48 hours you get a written scope, timeline and price. Sprints are fixed price and fractional work is billed by the day.
Who owns the code?
You do. Everything is built in your repositories and accounts wherever possible, and all rights transfer to you.
How much capacity do you have?
Tacklebear takes on a small number of projects at a time so each one gets senior attention. Ask about current availability and we'll tell you honestly.
Is there anything you don't take on?
One thing: projects for payment processors or crypto payment infrastructure companies, because of a conflict of interest with our founder's other work. Payments inside your own product are fine.
Got somethingto tackle?
Tell us what you need. You'll hear back within 24 hours with next steps and a ballpark price.