In-house feel, nearshore

MongoDB Developers

MongoDB sits under a great deal of British SaaS, and most of its production pain traces back to early schema and indexing decisions. We embed senior engineers who design document models, aggregation pipelines and APIs that stay fast as the data grows, working your team's hours as our full-time employees.

  • Deep in schema design, indexing and aggregation
  • At home in microservices, event-driven systems and content stores
  • Sitting inside your backend team through the British working day
Hire MongoDB Developers
Software engineer working at a dual-monitor dev workspaceAggregation PipelinesIndexing and PerformanceData MigrationsBackup and ReplicationAPI Integration

TRUSTED BY 300+ENGINEERING TEAMS

Virgin Experience Days
Salmon
Hotelplan
Willo
Travelex
Tidal
Scorpion
Vector
Virgin Experience Days
Salmon
Hotelplan
Willo
Travelex
Tidal
Scorpion
Vector
Ask our AI anything
Client onboarding call with a Cloud Employee engineer joining the team

Our Service

Pair-programmed vetting on real data problems

Every candidate works through a CTO-led process, a technical assessment, live pairing with a senior engineer on modelling and query tuning, then a cultural fit screen and a psychometric assessment we built for software engineers. AI can draft a pipeline stage these days; we are checking whether the candidate knows if it is the right one.

  • Matched for MongoDB alongside Node.js and wider backend work
  • Assessed on modelling judgement, not memorised operators
  • Employment, onboarding and retention stay on our side

Employment and retention stay with us

Where our MongoDB engineers add depth

  • Design scalable, flexible document schemas.
  • Aggregation PipelinesBuild efficient multi-stage transformations.
  • Engineer reviewing code on screen
  • Indexing and PerformanceOptimise indexes and slow-running queries.
  • Development team collaborating in the office
  • Data MigrationsPlan and execute safe schema migrations.
  • Backup and ReplicationConfigure replicasets for reliability.
  • API IntegrationConnect MongoDB layers to REST or GraphQL APIs.

The alternative

Get speed, fit and in-house feel without the hiring grind.

Cloud EmployeeIn-house hiringDev agenciesFreelancers
Speed to hire-
Flexibility to scale-
Developer fit (embedded)-
Full-time, only for you--
No overhead or upfront fees--

Solid lime = yes · outline lime = partial · grey dash = no

Vetting

You see two people - not 200 CVs.

Engineers vet engineers

A senior engineer runs a live technical conversation on the candidate's real stack, not a recruiter working from a keyword list.

Live coding, not take-homes

Real problems solved in front of an assessor, with anti-cheating checks. You see how they actually work, not what they submitted overnight.

A full profile, not a CV

Every candidate arrives with a CV, interview summary, coding-test breakdown and rate in pounds. You decide on evidence.

Every tab is a stage a candidate has to clear. Six of them, all run by our own internal engineers at Cloud Employee, before you see a name.

  • Overview
  • CV
  • Tech interview
  • Coding test
  • Psychometric
  • Soft skills

Scored by people. We use AI to cross-check our own consistency - never to decide who reaches your shortlist.

Vetted senior software engineer candidate profile

Luka M.

Vetted

Senior Software Engineer · TypeScript · Python · Cloud · 6 yrs · Zagreb, Croatia (GMT+1)

£4,900/moAvailable in 2 weeks

Assessment

Six years in production Python, the last three on LLM systems - retrieval pipelines, eval suites, and agent tooling for UK fintech. Owns delivery end to end.

Coding test88%
Live interviewStrong
PsychometricTop 9%
Stack
Python · LangGraph
English
C1 fluent
Overlap
8 hrs UK
Notice
2 weeks

AI in practiceShips with Copilot and Claude Code daily, and rewrote 40% of the generated code in his observed task - the judgement is his, the tooling only makes him faster.

Career history

2023 - now

Senior AI Engineer

UK payments platform · 40-person product team

Built the retrieval assistant now resolving 30% of tier-1 tickets; owns its eval suite and guardrails.

2020 - 2023

Backend Engineer, Python

Travel booking SaaS · Zagreb

Moved fraud scoring onto a real-time feature pipeline; cut false declines by 18%.

2019 - 2020

Data Engineer

Agency · Python, Postgres, AWS

  • Python
  • FastAPI
  • LangGraph
  • pgvector
  • Evals & tracing
  • AWS
  • Docker

Technical interview

Assessed by Marco R., Principal Engineer

12 Jun 2026
55 min · live call

System design4 out of 5
Code quality5 out of 5
Debugging4 out of 5
Communication5 out of 5

"Walked me through an assistant that was quietly hallucinating refund policy, how he caught it in evals, and what he got wrong on the first fix. Hire-ready for a senior seat."

Live coding test

Repair a leaking retrieval pipeline

Python 3.12 · pytest · observed screen share

88
score

Tests passed
21 / 21
Time used
62 of 90 min
Anti-cheat flags
0

retrieval.py · submitted diff

- hits = index.query(q, k=50)+ hits = index.query(rewrite(q), k=50, filter=tenant)+ hits = rerank(hits, q)[:8]  # recall 0.62 -> 0.91+ assert_context_budget(hits, max_tokens=6000)

Psychometric · technical thinking

How he reasons under a real deadline - not a personality quiz.

Top 9%of engineers
we test

Abstract reasoning92
Problem decomposition88
Attention to detail90
Learning agility94
Risk awareness82
  • Systems thinker
  • Root cause over quick patch
  • Asks before assuming

A 45-minute reasoning test, scored against the 4,000+ engineers we have already placed. Our assessors do the marking - AI only flags where our own scoring looks inconsistent.

Soft skills · working with your team

Communication5 out of 5
Ownership5 out of 5
Collaboration4 out of 5
Takes feedback4 out of 5
Spoken English
C1 · assessed on call
References
2 of 2 verified

"He raised the payment edge case nobody else had spotted, in writing, two days before release."

Reference check · former tech lead, UK payments platform

This is what you receive - not a CV.

Ask our AI anything

Why Cloud Employee?

Senior data engineering the budget can carry

You get one monthly fee, 50 to 75% below the fully loaded cost of a comparable British hire, on a rolling contract with 30 days notice. A UK-based client success manager stays close, a 1,000 pound annual learning budget keeps skills current, and 97% of our engineers stay beyond two years.

  • Reports into your backend lead like any teammate
  • HR, compliance and admin carried entirely by us
  • Two-week money-back guarantee plus free replacement
Long-tenure engineering team at work

Fully supported

We handle the rest so your engineers can focus on building.

Engineer in a performance review sessionPerformance reviews
Team member handling payroll and compliancePayroll & compliance
Dual-monitor engineering workstation and equipmentEquipment
Engineering team in a modern office workspaceWorkspace
Molly and Daniel on a welcome-to-the-team onboarding call

In-house, without the friction

No upfront fees. No lock-in contracts.

  • No placement or upfront fees
  • Rolling 30-day contract, cancel anytime
  • One monthly rate, everything included

Ready to find your engineer?

Tell us exactly who you need.
In 90 seconds

Two matched engineers in 7 days. No fees, no obligation.

What role are you hiring for?

Pick one to start - you'll see matching engineers at the end.

  • 300+ teams built
  • 97% stay 2+ years
  • Replace if it isn't working

Got questions?

The questions CTOs and founders ask.

Can't find your question?

Ask our AI chatbot, trained on every sales call we've had.

Open chat

Typically 50 to 75% less than a comparable British hire once salary, employer national insurance, pension, recruitment fees and overheads are counted. We do place UK-based MongoDB developers. Most clients choose Eastern Europe, the Philippines or Latin America, where quality matches and cost is lower, and Eastern Europe suits a British working day. The aim is the strongest quality-to-cost ratio we can find, strong database engineers at a sustainable price. Senior MongoDB experience in Britain sits mostly in well-funded scale-ups, which sets the local benchmark. A UK-based client success manager stays your point of contact.

MongoDB is a document database that stores data as flexible JSON-like documents instead of rows and tables, built to scale horizontally. Teams choose it when their data is naturally document-shaped, a product catalogue or a user profile, and when schemas need to evolve without migration ceremonies. Documents map cleanly onto application objects, and the aggregation pipeline handles serious queries inside the database. The flexibility has real costs, without discipline a schemaless store becomes a junk drawer, and heavily relational workloads fit worse than they would in Postgres.

Schema design is the paradox and the priority, because MongoDB does not force a schema, and that makes designing one more important, not less. Look for developers who model documents around access patterns, embedding what is read together and referencing what is not. Indexing literacy matters too, since most performance disasters are missing indexes, and a wrong shard key at scale is among the costliest mistakes in the ecosystem. AI assistants write passable queries and pipelines now, so an engineer who reviews a generated aggregation for index use beats one who merely produces it.

Assess a MongoDB developer through a modelling conversation, because schema design against access patterns is the skill everything else depends on. Describe a real feature and ask them to design the documents, then change the requirements and watch the redesign, since embedding versus referencing under shifting patterns is where understanding shows. Have them read an explain plan and diagnose a slow query, a short and brutally revealing exercise. Include AI in the session, watching whether they interrogate the generated pipeline's index behaviour or just admire its syntax. And ask when they would choose Postgres instead.

MongoDB developers remain solidly in demand, because the database sits inside an enormous number of production systems and someone has to run them well. It is one of the most widely deployed databases in production use, so the skills travel and the market for them is liquid. Vector search support has given it a role in AI products, with teams adding semantic retrieval to data they already hold rather than bolting on a separate store. As a foundation it is a reasonable bet where document data dominates, though relational workloads still belong in relational databases.

Yes, our developers use AI assistants for MongoDB work, and the soundness discipline centres on the database's specific failure modes, which generated code walks into readily. Assistants produce queries and pipelines that are syntactically fine and operationally naive, no thought for indexes or memory limits, so engineers review generated database code against explain plans before it ships. These verification habits are assessed during vetting, in live pairing with a senior engineer, and we test whether candidates use AI tooling well. Internally the same rule holds, AI accelerates screening and matching, humans make the decisions.

MongoDB developers pass our four-stage, CTO-led vetting, judged by engineers who have run production databases rather than recruiters pattern-matching CVs. The stages are a technical assessment, live pairing with a senior engineer, a cultural fit screen and a psychometric assessment for software engineers. Pairing leans on data modelling and query diagnosis, and includes watching candidates verify what their AI tools generate. Matched candidates interview within 7 working days, are embedded in about two weeks, and are covered by a two-week money-back guarantee and free replacement. 97% of the engineers we embed stay beyond two years.

You are typically interviewing matched candidates within 7 working days of a requirements call, and developers are often embedded and pushing code within about two weeks. From there it is a rolling monthly contract with 30 days' notice, one monthly fee, and no placement charges. You can scale up or down as the work changes, and you pay nothing to interview.

There is a two-week money-back guarantee, and if you want to continue we replace the developer free of charge. In practice this rarely comes up, because you interview a shortlist of two candidates who have already passed a CTO-led technical assessment and a live pair programming session, so the fit question is largely settled before anyone starts.

Proof, not promises

Hear from our customers

In their words

What the difference feels like

Our new developers were able to hit the ground running, we've worked with them for over two years now, and they are truly part of our team.

Alison WhittleAlison WhittleProduct Delivery Manager, BladeFS

What I love about Cloud Employee is that you have taken all of that hard work off my shoulders.

Marcus KilgourMarcus KilgourCTO, Salmon Software

Working with Cloud Employee developers is great, because they're not afraid to push back. They're proactive, they're positive, and they feel like part of the team.

Doran EskinaziDoran EskinaziHead of Engineering, Healthpointe

We actually hired the whole team remotely, having never met them. And we made a bunch of really good hires.

Euan CameronEuan CameronCEO, Willo

Cloud Employee provides a level of professionalism, communication and support we haven't found elsewhere.

Trevor SathorTrevor SathorManaging Director, Square Eye

Working in tandem with Cloud Employee we have successfully released a major version of our main software product during a critical period for us.

James StringerJames StringerManaging Director, CleanLink