Enterprise software engineering · Tallinn, Estonia
Custom software development, IT architecture consulting and high-performance API engineering since 2009. 021 OÜ is an EU-registered engineering company — every engagement starts with a written specification and ends with the source code in your hands.
Operating for 16 years · Registered 05.10.2009 · verify in the public register
src/components/OrderBoard.tsx
main$npm run build — 412 modules, 0 errors
16+
Years operating
Registered 05.10.2009 in the Estonian e-Business Register (Äriregister).
EU
Jurisdiction
Estonian Osaühing (private limited company), VAT-registered as EE101488194.
3
Engagement models
Fixed-scope delivery, dedicated team, and advisory retainer.
1
Business day reply
Every consultation request is answered by a named engineer.
Every figure above is derived from our entry in the Estonian e-Business Register or from our standard contract terms. We do not publish client names, logos or project counts we are not contractually free to evidence — references are provided under NDA on request.
Core IT services
Each one is scoped, priced and contracted separately, so you can start with the piece that is actually blocking you.
Custom web & mobile architecture
Custom business applications built to a written specification: domain modelling, architecture, implementation, automated tests and handover of the full source code.
AWS, Azure, microservices
Cloud architecture, migration planning and DevOps automation for teams moving off single-server hosting or bringing an unmanaged cloud estate under control.
Integration and system replacement
Designed, versioned and documented APIs, plus staged replacement of legacy systems that cannot be switched off in one go.
Staff augmentation from the EU
Named engineers working inside your process — your board, your standups, your definition of done — contracted monthly from an EU-registered company.
How we work
The same four phases whether the project is a six-week integration or a multi-team programme.
Phase 01
A paid or complimentary discovery session, depending on scope. We document the current systems, the constraints and the success criteria in writing before quoting anything.
Phase 02
Target architecture, data model, integration contracts and a phase plan. You receive the document whether or not you continue with us.
Phase 03
Two-week iterations against the agreed backlog, with a demonstrable increment and a written progress report at the end of each one.
Phase 04
Load and security testing, runbook, backup verification, knowledge transfer, and transfer of repositories and infrastructure accounts to the client.
Solutions
Problem · Critical processes live in spreadsheets that only one person understands.
Model the process, move it into an auditable application with roles and permissions, and keep an export path so the data is never trapped again.
Problem · ERP, CRM, warehouse and accounting systems each hold a different version of the same record.
Define the canonical record, put a versioned API in front of each system, and reconcile continuously rather than in a nightly batch nobody checks.
Problem · A single unmanaged server is the whole production environment, and nobody has tested the backups.
Assess, describe the target estate as code, migrate in reversible stages, and prove the restore path before the old server is retired.
Problem · A business-critical application runs on an unsupported runtime and cannot be switched off.
Wrap the legacy system, route traffic through a new contract, and replace one capability at a time until nothing is left behind it.
Technology
We pick the boring, well-supported option unless there is a written reason not to — the client has to be able to hire for it after we hand over.
Front end
Typed, accessible interfaces that render fast on mid-range hardware.
Back end
Services with explicit contracts, prepared statements and audit trails.
Cloud & DevOps
Environments defined as code, so a rebuild is a pipeline run.
Data
Schemas designed for the queries the business actually runs.
Principles
Scope, data model and acceptance criteria are agreed in writing before the first commit. You get the document whether or not the project continues with us.
Repositories, schemas, infrastructure definitions and documentation transfer to you on payment. No licence-back, no runtime dependency on us.
Migrations run in stages with a rollback point at each one. Nothing goes to production without a tested way back.
Engagement models
A defined system with stable requirements and a written specification.
Milestone-based, agreed before work starts
A continuing roadmap that outlives any single project.
Monthly rolling, 30-day notice
An in-house team that needs architecture review and a second opinion.
Capped hours per month
Next step
Our scope calculator turns your answers into an indicative engagement shape — phases, duration band and team composition — and sends it to an engineer, not a sales queue. You get a written reply within one business day.