Available for project work

The backend your team
doesn't have time to build.

If you have a defined problem and need it solved — not a six-week discovery phase — I scope it, build it, and hand it over. Solo, fast, and without ceremony.

Who this is for

This is a fit if you know what the problem is but don't have the capacity to build the solution.

  • Your team is frontend-heavy and you need someone to own the backend side of a feature or product
  • You need an integration, a tool, or a system built in weeks — not explored across quarters
  • You're on managed infrastructure that costs more than it should, and want a clean self-hosted alternative
  • You have a manual process, a spreadsheet workflow, or a webhook flow that should be a proper tool
  • You need a billing layer, a Stripe integration, or a subscription flow done correctly the first time
  • You want a content automation pipeline that publishes at scale without ongoing manual work

Not every engagement is a fit. If the scope is undefined and the problem is still being discovered, that's not where I add value. I work best when you can describe what done looks like.

What I build

Concrete deliverables, not consultancy output. Stack: Go, Node.js, vanilla JS. Self-hosted on OVH or your provider.

[ webhooks ]

Event systems & webhook infrastructure

Ingestion, deduplication, delivery, retry logic, receipt verification. Built on the same architecture that runs DueRelay in production.

[ integrations ]

API integrations & billing layers

Stripe subscriptions, payment flows, third-party service connections, REST and webhook-based workflows. Done once, done properly.

[ tools ]

SaaS tools & calculators

Single-purpose, fast to ship. From single-file HTML tools to full-stack applications with authentication and a billing tier.

[ content ]

Content automation pipelines

WordPress and Ghost setup, REST API publishing pipelines, programmatic content generation and scheduling. SEO-structured from the start.

How it works

Three stages. No ambiguity at any of them.

01 — Brief

Describe the problem

Send a written description: what you need built, the constraints that matter, and your timeline. Not a call request — a clear document. The better the brief, the faster the scope.

02 — Scope

Agree on what gets built

I outline what I'll deliver, when, and at what rate. One round of revision if needed. The scope is the contract — no scope creep, no ambiguous deliverables.

03 — Deliver

Clean handover

I build it, deploy it if included in scope, and transfer everything. Full source code, running deployment, and enough documentation that your team can maintain it independently.

Rates

All engagements are EU-based and properly invoiced. No hidden costs after the scope is agreed.

Project-based
From €1,500

Most engagements

Defined scope, flat rate agreed upfront. Small tools and integrations from €1,500. SaaS features and backend systems from €3,000. Larger builds quoted per scope.

  • Fixed price, no surprises
  • Milestone payment for larger projects
  • Deposit required to start
Full details →
Hourly
€100/hr

Advisory & smaller tasks

For code review, architecture consultation, or well-defined tasks that don't warrant a full project scope. Minimum 4 hours. Billed weekly.

  • Minimum 4 hours per engagement
  • Billed weekly with time log
  • Available on short notice
Full details →
Retainer
From €2,500/mo

Ongoing development

Fixed monthly capacity for teams that need ongoing backend development without hiring. Priority response, weekly delivery, 2 weeks notice to start or end.

  • Dedicated weekly capacity
  • Priority response time
  • Month-to-month, 2 weeks notice
Full details →

All rates are net. VAT applied where applicable under EU regulations.

Send a brief

Describe the problem, the scope, and your timeline. I respond within 24 hours with either a follow-up question or a proposed scope.

If you'd rather email directly:

office@constantin-works.com

Opens your email client. No server-side processing.