API development & integrations

API Development & Integration Services for Web, Mobile & SaaS Products.

QalbIT designs and builds secure, well-documented REST APIs, webhooks and microservices that connect your products, mobile apps and third-party platforms. We focus on reliability, clear contracts and a good developer experience so your teams can move faster.

Discuss your API project See integration-style case studies

Typically responding within 24–48 hours. Share your current product stage, tech stack and timelines.

API development overview

API development and integration services for scalable products

We help product and engineering teams design, build and maintain APIs that are secure, consistent and easy to integrate. Whether you need a new REST API, webhooks, or a migration from a legacy integration, we focus on clear contracts and predictable behaviour.

When API development with QalbIT makes sense

  • You need a secure REST API or webhooks to power your web, mobile or SaaS product.
  • You want to replace fragile point-to-point integrations with a cleaner API layer.
  • You are adding third-party APIs (payments, CRM, logistics, etc.) and need them to work reliably.
  • Your existing APIs are slow, hard to change or poorly documented, and you want to modernise them.
  • You prefer a senior, founder-led team that understands both architecture and real-world constraints.

Outcomes we usually target with API projects

  • Consistent, well-versioned APIs that are easier for internal and external teams to adopt.
  • Faster and more reliable integrations between your products, mobile apps and third-party services.
  • Improved security with proper authentication, authorisation, validation and rate limiting.
  • Better observability and logging so API issues can be detected and resolved quickly.
  • Clear API documentation and examples that reduce onboarding time for developers.

For most API projects we start with a short discovery sprint to map your systems, data contracts and integration points, then define a practical API design and rollout plan.

What we build with APIs

API development capabilities across products and platforms

From internal APIs powering mobile apps to public-facing developer platforms, we cover the full lifecycle – design, implementation, documentation, security and long-term maintenance.

API design & specification

Design

API design & specification

Design clear, consistent REST API contracts with versioning, error formats and pagination, captured in OpenAPI/Swagger specs so teams can integrate with confidence.

REST APIs for web & mobile

Development

REST APIs for web & mobile

Build secure REST/JSON APIs that power your web frontends, mobile apps and third-party clients with proper authentication, rate limiting and performance optimisation.

Webhooks & event-driven integrations

Events

Webhooks & event-driven integrations

Implement webhooks and event-driven patterns so your systems can react in real time to changes in payments, orders, tickets and other external events.

Third-party API integrations

Integrations

Third-party API integrations

Integrate with CRMs, ERPs, payment gateways, communication platforms and other APIs using robust error handling, retries and monitoring.

Security, auth & rate limiting

Security

Security, auth & rate limiting

Implement OAuth2, JWT, API keys, IP whitelisting, throttling and input validation to protect your APIs and the data they expose.

Monitoring, logging & lifecycle

Ops

Monitoring, logging & lifecycle

Set up logging, monitoring, alerting and API lifecycle practices so you can deprecate old versions gracefully and keep integrations stable.

Want to see how these capabilities map to your product? Share a quick overview and we will respond with a practical next step.

Discuss your API and integration scope →

How API projects work with QalbIT

A practical API development process from design to stable integrations

We keep the API process structured but not heavy, so you get a clear contract, reliable implementation and the monitoring needed to support production traffic.

  1. 01

    Discovery & integration mapping

    1–2 weeks

    Discovery & integration mapping

    Understand your systems, data flows, consumers and third-party APIs. Identify what needs to be exposed, what should stay internal and how existing integrations behave today.

    Key outcome: System and data flow map, list of integration points and a prioritised API backlog.

  2. 02

    API design & specification

    1–3 weeks

    API design & specification

    Define endpoints, resources, authentication, error formats and versioning strategy, documented using OpenAPI/Swagger and practical examples.

    Key outcome: Reviewed API specification that product and engineering teams agree on.

  3. 03

    Implementation & testing

    3–8+ weeks (scope-dependent)

    Implementation & testing

    Implement APIs or webhooks with proper validation, security and logging, plus automated tests and integration tests where appropriate.

    Key outcome: Production-ready APIs or webhooks deployed in your environment.

  4. 04

    Integration, docs & launch

    First 2–6 weeks after go-live

    Integration, docs & launch

    Support your internal or external teams as they integrate, refine documentation and examples, and roll out the APIs to real consumers.

    Key outcome: Live integrations with clear docs, examples and support channels.

  5. 05

    Monitoring & evolution

    Ongoing, month-to-month

    Monitoring & evolution

    Monitor usage and performance, fix edge cases, plan new versions and gradually evolve the API as your product and ecosystem grow.

    Key outcome: Stable API layer that can safely support new features and integrations.

Want to see how this process applies to your current stage? Share a short brief and we will respond with a tailored next step.

Walk me through this API process for my product →

Where APIs make the biggest impact

API development and integration use cases we most often deliver

Most of our API work connects existing products, mobile apps and third-party services, or replaces fragile legacy integrations with a cleaner, more scalable API layer.

APIs for mobile app backends

For Product teams and mobile developers

Mobile backends

REST APIs and webhooks that power your iOS and Android apps with authentication, profiles, payments, notifications and more.

Ask how we structure mobile app APIs →

Partner & public APIs for SaaS products

For SaaS founders and product teams

SaaS APIs

APIs that let partners, agencies or customers integrate your SaaS with their own systems, including keys, rate limiting and usage tracking.

Discuss a partner API for your SaaS →

Internal integration layer

For IT, operations and architecture teams

Integration

APIs and services that sit between legacy systems, ERPs, CRMs and new products, reducing point-to-point complexity.

Migration from legacy or ad-hoc integrations

For Growing businesses with legacy systems

Modernisation

Rebuilding brittle integrations into a cleaner REST or event-driven architecture while keeping existing customers and data safe.

Not sure if your idea or system belongs here? Send us a short description and we will tell you honestly whether we are the right team for it.

Ask if your API needs fit these use cases →

Tech stack & tooling

API stack and tooling we typically use at QalbIT

We choose API stack and tooling based on your existing systems, team skills and compliance needs. The goal is to keep APIs maintainable, observable and aligned with your wider architecture.

Backend & API frameworks

Core application logic and REST API implementation.

  • Laravel 10/11/12 (PHP 8.x) for modular REST APIs and microservices.
  • NestJS (TypeScript, Node.js 20+) for API-first and event-driven architectures.
  • Background jobs, queues and schedulers for async processing.

API design & documentation

Tools for consistent API contracts and developer experience.

  • OpenAPI/Swagger specs for REST endpoints and data models.
  • Postman collections and examples for faster onboarding.
  • Style guides for naming, versioning and error handling.

Security, auth & access control

Protecting APIs and the data they expose.

  • OAuth2, JWT and API key-based authentication patterns.
  • Rate limiting, throttling and IP whitelisting where required.
  • Validation, sanitisation and secure coding best practices.

Observability & operations

Keeping APIs healthy in production.

  • Structured logging and centralised log aggregation.
  • Metrics, uptime monitoring and alerting around key endpoints.
  • Deployment pipelines for safe, repeatable releases.

If you already have live APIs, we will review your current stack and only recommend changes where they clearly improve reliability, performance or maintainability.

FAQs · Custom software & teams

Frequently asked questions about API development with QalbIT

These are the API development and integration questions product owners and tech leads usually ask when we discuss new APIs or modernising existing integrations.

  • ✓ Covers custom software development, SaaS platforms, mobile apps and integrations.
  • ✓ Answers about pricing, engagement models, NDAs, IP ownership and quality assurance.
  • ✓ Written for founders, CTOs and product teams hiring a remote development partner.

Have a question that is not listed here?

Share your roadmap or idea and we’ll help you pick the right engagement model, tech stack and starting point.

Contact our experts

What types of APIs does QalbIT develop?

We primarily build REST/JSON APIs over HTTP, internal APIs for web and mobile apps, webhooks for event-driven integrations and, where it makes sense, selected GraphQL endpoints. We also create integration layers that sit between your existing systems and third-party platforms such as CRMs, ERPs, payment gateways and communication tools.

Can you integrate our product with third-party APIs and legacy systems?

How do you ensure the APIs you build are secure?

How is API documentation handled?

What does a typical API development timeline look like?

Can you maintain and evolve the APIs after launch?

Do you only work on greenfield APIs, or can you improve existing ones?

Ready to talk APIs & integrations?

Let’s design a secure, reliable API layer for your product.

Share how your systems talk to each other today and where you are running into limits. We will review your goals, current architecture and constraints, then suggest a practical API roadmap that fits your product and team.

Book an API discovery call Ask about modernising existing APIs

Typically we respond within 24–48 hours with next steps and an initial API approach.