Subcontracting · Python

A Python developer for your project: back end, integrations, data

I build Python systems that have to work every day: sales automation, banking and bookkeeping integrations, and production pipelines that use AI. Next to Django, Flask and FastAPI, my daily tools are SQLAlchemy, Celery, Redis and PostgreSQL.

Within a weekstart
€70/h excl. VATrate
Django, Flask, FastAPIcore
Remote or hybridmode

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Projects that relate to this

Three Python systems in production. In each I owned the architecture, the code and the deployment.

B2B CRM & lead automation

Architect & sole developer · In production · 2026 to present

Lead acquisition, enrichment, campaign sequences and a sales pipeline on one platform

A campaign engine: multi-step sequences, message variants with A/B testing (multi-armed bandit), condition-based branches, automatic actions and recipient enrollments.
An enrichment chain where every contact passes through paid and free sources (PDL → Hunter → ZeroBounce → Gemini) until it has a verified, deliverable email address and a reasoned company context.
Container-free production deployment: systemd + Nginx + native PostgreSQL. Development runs on Podman Compose with local overrides.

39+domain models

PythonFlask 3.1SQLAlchemy 2.0PostgreSQL 16React 19Vite 8CeleryRedis

Why it matters: Flask, SQLAlchemy and Celery in production, with integrations and scheduling built in.

Automated accounting system

Architect & developer · In daily use · 2026 to present

End-to-end bookkeeping automation for a sole trader, a limited company and a personal account.

Automatic receipt collection through the Gmail API (OAuth2), email-to-PDF conversion, and matching each receipt to the right transaction by amount, date and counterparty.
Idempotent publishing into Firefly III: transactions are keyed by external_id, so re-running never creates duplicates. The Finnish chart of accounts is mapped to Firefly categories, budgets are read from a Google Sheets plan, PDF receipts are attached to their transactions.

2banks integrated0duplicates (idempotent)

PythonGmail APIGoogle Sheets APINordeaHolviFirefly IIISQLiteGemini

Why it matters: Gmail, Sheets and bank APIs, idempotent: a rerun never creates duplicates.

SKT quoting software: computer vision for job costing

Architect & developer · Active client project · 2026 to present

Building assessment and window-cleaning cost estimation for the Helsinki metro area

A 10-phase pipeline: Oikotie scraper (cards, details and photos) → Digitransit geocoding → Google Street View (URL-signed) and Mapillary → Claude Sonnet Vision → man-hour formula v2.0 with a v3.0 refinement → a proposal from a single command.
Cost tracking for every LLM call with its own self-test, so the price of vision analysis stays visible before a run is scaled to hundreds of targets.

10pipeline phases584management offices

Python 3.11Claude Sonnet VisionGoogle Street ViewMapillaryDigitransitSQLiteStreamlitDocker

Why it matters: A multi stage data pipeline where the output and the cost of every stage are visible.

How we start

For Python work the first week usually goes into one bounded piece: an API, a job or an integration.

Send the task and the stack

In a few lines: the project, the technologies, the timeline. I answer the same working day with my CV and the two closest examples of my work.

A scoped first week

I start with a small, clearly bounded task in your repository and your tools. At the end of the week you see the code and decide what happens next.

Invoices every two weeks

Hours go into your tracker, the invoice comes from GG Solutions Oy. No lock in: we continue for as long as it is useful to you.

Terms

Trial week: 25 hours on a bounded task, fixed €1,750 excl. VAT
Rate: €70/h excl. VAT; longer engagements or a fixed scope are agreed separately
Invoicing: GG Solutions Oy, Finnish Business ID 3465139-7, every two weeks by the hour; EU reverse charge where it applies
Contract: IT2018 terms or your own template; confidentiality, and the rights to the code are yours
Capacity: 20 or 40 hours a week, usually starting within a week
How: Remote, or hybrid from Helsinki; your repositories, tickets and chat
Languages: English, Finnish and Russian

Questions

Are you a freelancer or a company?

A company: GG Solutions Oy, Finnish Business ID 3465139-7. I invoice hours or an agreed scope. I am not looking for employment.

What do you not do?

Java, .NET, native mobile and PLC programming. The core is Python, PHP and Laravel, React and TypeScript, PostgreSQL and MySQL, Docker and AI integrations.

Can your end client interview you?

Yes. Many end clients want their own interview and a CV with references, and both are fine.

What if it does not work out?

The first week is a bounded task. If the result does not convince you, we stop there and you pay only for the hours worked.

Which time zone?

Central and Northern European working hours are covered. I work remotely, or hybrid from Helsinki.

Tell me what Python needs to get done

Send the stack, your repository conventions and the timeline. You get my CV and the two closest examples the same working day.

jyri.gromyko2002@gmail.com +358 44 978 2028

Tell me about the task Download CV (PDF)

Other pages

Full CV and all projects Subcontracting for software houses Laravel and React as a subcontractor AI engineering as a subcontractor Integrations: ERP, banks and POS WooCommerce development for agencies AI for everyday business work