--- title: "Backend development" description: "Node.js and TypeScript services, APIs, databases and background jobs with validation, permissions and operations considered from the start." canonical: "https://juhenza.com/solutions/backend-development" last-updated: 2026-10-15 --- # Backend development > Node.js and TypeScript services, APIs, databases and background jobs with validation, permissions and operations considered from the start. ## The system behind the screen. Reliable products are decided in the backend: validation, permissions, data integrity and failure handling. We build Node.js and TypeScript services, APIs and data layers that behave predictably under real use. ## Fit For teams building a new service, exposing a safe API, or replacing scripts and spreadsheets with a dependable system of record. ## Scope - **APIs & service layers:** Documented REST or RPC APIs with explicit validation, authentication, rate limits and error contracts that frontend and partner teams can build against. - **Databases & data modelling:** Schema design, migrations and query work around the real shape of your data — including the history and audit trails your operations need. - **Integrations & background jobs:** Connections to third-party services, queues and scheduled work with retries and idempotency, so temporary failures do not corrupt records. - **Auth, permissions & audit:** Identity, roles and permission checks enforced at the service layer — not just hidden in the interface — with the records to review what happened. ## Process 1. **Model the domain:** Agree entities, ownership, validation rules and what the system must never lose before choosing infrastructure. 2. **Build with contracts:** Develop services against documented contracts with automated checks for the rules that matter. 3. **Operate deliberately:** Agree deployment, backups, monitoring and who responds when something fails — before launch, not after. ## Examples ### A new API product - Challenge: A product needs a public API that partners can integrate without endangering the platform. - Approach: Define the contract first — endpoints, limits, versioning and error behaviour — then build with validation and monitoring from the first release. - Deliverable: A documented, versioned API with keys, limits and operational dashboards. ### A system of record - Challenge: Critical business data lives in spreadsheets with no access control, history or backup. - Approach: Model the entities and rules, import the existing records with validation, and provide roles, history and exports. - Deliverable: A backed-up, permissioned system of record with imported data and an audit trail. ### Backend rescue - Challenge: An existing service fails under load, silently drops jobs or cannot be changed safely. - Approach: Add observability and tests around the critical paths, then fix the failures in priority order with rollback safety. - Deliverable: A stabilised service with monitoring, regression tests and a prioritised fix list. ## FAQ ### Which databases and runtimes do you work with? Jainil's experience centres on Node.js, TypeScript, SQL databases, Docker and Linux. The database and runtime for a project follow its data shape, consistency needs and the team that will maintain it. ### Can you integrate with our legacy system? Usually, yes — through its API, database, file exports or a staged migration. The honest answer comes from a short review of what the system actually exposes and who owns each field. ### Who owns the code and infrastructure? You do. Deployment access, secrets, backups and documentation are handed over as part of the work, so the system is never held hostage. ## Reference architecture A reference backend structure. Validation, permissions and failure handling live in the service layer, where they cannot be bypassed. ### Interface API contract → Validation & auth Define the documented requests the service accepts, with identity and input checks applied before any rule runs. Review: Check malformed input, expired sessions, rate limits and that error responses are consistent and documented. ### Domain Business rules → Data access Apply the rules behind each workflow against a schema that reflects how the data is really used and retained. Review: Test duplicate submissions, concurrent edits, permission boundaries and migration rollback. ### Edges Integrations & queues → Operations & logs Handle third-party calls and background work with retries that cannot corrupt records, and log enough to diagnose failures. Review: Rehearse provider outages, failed jobs and restore procedures; confirm logs carry an owner. Illustrative planning model; scope and deliverables are agreed per project. ## Technology choices Validation and permissions at the service edge ### Services Node.js · TypeScript · API framework Define contracts, validation and error behaviour in typed code that frontend and partners can rely on. ### Data SQL databases · Migrations · Audit fields Model entities, history and retention around real usage, with migrations that can be rehearsed and rolled back. ### Runtime Docker · Linux · Monitoring Package and run services with explicit resource limits, health checks and logs routed to an owner. ## Quality checks before handover ### Contract tests Verify documented request and response behaviour, including malformed input and authorization failures. ### Failure rehearsals Test provider outages, duplicate jobs and interrupted deployments against the agreed retry and rollback rules. ### Operable handover Confirm deployment, backup, restore and log access are documented and usable by the owning team. ## Preparing for a project Bring your data model or sample records, the systems to integrate, expected usage levels and any compliance or retention requirements. 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