Backend feature delivery
Tickets off your board, taken to production through your own review and release process.
Senior backend contractor · Europe · PHP and Go
Senior Backend Engineer Inside Your Team, Without Another Payroll Hire
PHP, Go, APIs, distributed backend systems and legacy modernization. Add experienced backend capacity without opening another permanent position.
One B2B agreement. Monthly EUR invoice. CET/CEST overlap.
Serbia-based · CET/CEST · B2B contract · EUR invoicing · English communication
What I Can Own
Not a list of technologies I have heard of. These are the areas where I can take responsibility for the outcome rather than needing supervision.
API design
HTTP and gRPC contracts, versioning, pagination, idempotency and the error semantics clients actually need.
Go services
New services and workers in Go, including the operational parts: configuration, health checks, graceful shutdown.
PHP, Symfony and Laravel
Feature work and repair inside existing applications, including the areas nobody on the team wants to touch.
Legacy modernization
Runtime and framework upgrades, dependency untangling, and removing the constraints that dictate estimates.
Architecture improvements
Module boundaries, data ownership, and decisions written down so the next change does not reopen them.
Production incidents
Debugging live systems, then closing the loop with the fix, the alert and the note that stops a repeat.
PostgreSQL
Schema and index design, query plans, migrations on large tables, and the locking behaviour behind them.
Redis
Caching strategies with invalidation that holds up, plus locks, rate limits and queue backends.
Queues and workers
Retry and dead-letter policy, idempotent consumers, backpressure and throughput work.
Kubernetes and cloud backend work
Manifests, resource limits, probes, and the deployment and rollback path around a service.
Technical debt reduction
Paying down the debt that is measurably slowing delivery, in an agreed order, rather than a rewrite crusade.
Engagement Models
Four shapes cover most situations. The difference between them is how much of the week is involved and whether the work is execution, technical direction or repair.
3–5 days per week
Embedded Senior Backend
For teams that already have a backlog and need senior execution against it. I work inside your process, your repository and your standups, and own features end to end.
1–2 days per week
Fractional Backend Lead
Architecture, code review, technical decisions and mentoring. For teams whose engineers are capable but have nobody senior to pressure-test a design before it is built.
4–8 week engagement
Legacy Rescue
A time-boxed engagement for systems carrying accumulated technical debt or reliability problems, aimed at a specific agreed improvement rather than an open-ended cleanup.
1–3 months
Senior Cover
Temporary senior capacity while you search for a permanent hire, or while someone is away. Delivery keeps moving and the recruitment process stops being urgent.
The one and two day per week variants are what people usually mean by a fractional backend engineer, and the trade-offs of that arrangement are worth reading before you choose a cadence. There is also a longer write-up on working with a senior Go contractor in Europe.
Senior Capacity Without Another Employment Process
One B2B agreement
A single service contract between two companies. No employment relationship, no payroll entry, no HR process.
Monthly EUR invoice
One invoice per month in euro from a registered business in Serbia, with whatever reference or purchase order number your finance team needs on it.
No employer of record
No EOR provider and no umbrella company in the middle, so there is no third-party margin and no additional contract to administer.
Flexible engagement volume
Days per week are agreed up front and can be revised between months as your roadmap changes.
Clearly defined termination clause
The notice period sits in the contract in writing, so ending the engagement is an administrative step rather than a negotiation.
Own business entity
A registered business in Serbia with its own tax registration, invoicing and liability. Your compliance team has a counterparty it can check.
CET/CEST working hours
Real overlap with teams in Germany, the Netherlands, France, the Nordics and the rest of the EU, for reviews, incidents and planning.
Company details on request
Registration and tax details are ready when your procurement process asks for them.
Start with a 10-day paid pilot and make an easy stop/continue decision. Ten working days is enough to ship something real and to see how the collaboration actually works, and short enough that stopping afterwards costs you almost nothing.
Simple Commercial Model
Day rate
€400/ dayEmbedded and fractional backend work
Migration implementation is priced separately, because it is scoped after discovery rather than guessed up front.
Typical engagements
| Cadence | Billable days | Approximate monthly |
|---|---|---|
| 2 days per week | about 8 | €3,200 |
| 3 days per week | about 12 | €4,800 |
| Full-time-equivalent | scoped separately | on request |
Approximate monthly figures at €400 per day, assuming about four billable weeks. The exact amount depends on how the month falls and on the days actually worked.
What you are buying is senior ownership of backend work without a permanent hiring commitment. If the decision comes down to the cheapest available day rate, there are better options than me.
Contracting
The engagement runs on one B2B service agreement between your company and mine. An NDA can be signed before any code or architecture discussion, in your template or mine.
Anything else your process requires, send it over and I will review it with you. Your legal and compliance teams drive the wording.
Working stack
- PHP
- Symfony
- Laravel
- Go
- PostgreSQL
- MySQL
- Redis
- REST / gRPC APIs
- RabbitMQ
- Docker
- Kubernetes
- CI/CD
Remote from Serbia, working hours overlapping CET/CEST. Engagements run on one B2B agreement with a monthly invoice in EUR.
If the Real Problem Is the Legacy Platform
Sometimes a shortage of backend capacity is a symptom. If every estimate is inflated by the same ageing PHP platform, adding a pair of hands to the existing backlog will not change the trajectory, the architecture decision has to be made first.
Questions European Teams Usually Ask
What does a typical engagement look like?
An agreed number of days per week, worked inside your repository, your tracker and your review process, against tickets that already exist. I join the standups and planning sessions that matter for the work and stay out of the ones that do not. Communication is mostly asynchronous, with overlap in CET/CEST for reviews, pairing and incidents. Scope is reviewed monthly, so the volume of days can move with your roadmap instead of being locked in for a year.
Are you a contractor, an agency, or an employee?
An independent contractor with my own registered business, working as one engineer. There is no agency in the middle, no bench of people you have not met, and no employer of record adding a margin and a second contract. That also means capacity is finite and honest: when I am booked, I say so rather than substituting someone else. The arrangement is a straightforward business-to-business service contract.
How does invoicing work for an EU company?
One invoice per month, in euro, from a registered business in Serbia. Because Serbia is outside the EU, your finance team will normally handle it under whatever process they already use for services bought from a non-EU supplier, and your own tax advisor should confirm the exact treatment for your jurisdiction. I provide the company details, tax registration and purchase order references that process needs. Payment terms are agreed in the contract rather than assumed.
What hours do you work?
CET/CEST, which means a full working-day overlap with teams in Germany and the wider DACH region, the Netherlands, France, the Nordics and most of the EU. Core hours for meetings and reviews are agreed at the start of the engagement. Incident participation and any out-of-hours expectations are also agreed up front rather than being assumed to be included.
Can we start with something small?
Yes, and that is the recommended way in. Start with a 10-day paid pilot and make an easy stop/continue decision at the end of it. Ten days is long enough to ship something real, see how the collaboration works and get a genuine assessment of your backend, and short enough that stopping costs you very little. If it continues, the pilot rolls into a regular cadence without a new procurement cycle.
What if what we really need is a permanent hire?
Then hire one, and use Senior Cover in the meantime. A permanent senior backend engineer is often the right long-term answer, but the search takes months and delivery does not pause while it runs. A temporary engagement keeps the roadmap moving, and it can also help the hiring process: the architecture notes and the codebase cleanup produced along the way make onboarding the eventual hire considerably faster.
Next step
Tell me what the team is short of
The stack, the size of the team, and what you would hand over first. You get a straight answer about whether I am a fit, what I would start with, and when I could actually begin.