Logoleetsoft
Services

Services

  • Web Development
  • Mobile Development
  • Custom Software Development
  • AI & Automation
  • SEO, AEO & GEO Optimization
  • MVP Development
  • Dedicated Development Team
  • API Development & Integration
  • QA & Software Testing
  • Cloud Deployment & Infrastructure
  • Legacy Software Modernization
  • Software Architecture Consulting
  • E-commerce Development
  • Data Engineering & Analytics

Industries

  • Automotive Software Development
  • Fitness & Wellness App Development
  • FinTech Software Development
  • Healthcare & Wellness Software
  • Real Estate & PropTech
  • Logistics & Supply Chain Software
  • EdTech Software Development
  • Travel & Hospitality Software
  • Retail Technology & POS
  • Insurance Software Development
  • EN
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  • RU
  • UA
  • EN
  • ES
  • RU
  • UA

API Development & Integration Services

We connect the systems your business already runs on, so data moves between them without manual work or duplicate entry. Our team has built API integrations as part of larger platform work, including a dealer management platform that ties ERP, telephony, and messenger systems together across a multi-region dealer network, and a CRM platform with real-time data sync across multiple business locations. If you need custom API development or a legacy system connected to a modern stack, we offer that as a standalone engagement.

API development and integration services we provide

01
REST & GraphQL API design
We design APIs that are consistent, versioned, and documented, so internal teams and external partners can build against them without guesswork.
02
Third-party API integration
We connect payment processors, CRM platforms, analytics tools, and messaging services, handling authentication, rate limits, and data mapping for each one.
03
ERP & legacy system integration
We build the connectors and API layers needed to link ERP and older internal systems to newer tools, including telephony and messenger platforms.
04
Real-time data synchronization
We design sync logic that keeps data consistent across multiple systems and locations as it changes, not on a delayed batch schedule.
05
Webhook & event-driven integrations
We set up webhook listeners and event-driven pipelines so systems react to changes as they happen, instead of polling for updates.
06
API security & error handling
We implement authentication, rate limiting, and structured error handling so integrations fail safely and recover without data loss.

Our API integration process

  1. 01

    Audit of existing systems and APIs

    We review what you already have: which systems exist, what APIs they expose, where data currently breaks or duplicates.

  2. 02

    Integration architecture design

    We map how data should flow between systems, choose the right pattern (REST, GraphQL, webhooks, event-driven), and document it before writing code.

  3. 03

    Development

    We build the API layer, connectors, and sync logic, following the architecture and your existing coding standards.

  4. 04

    Testing against real data flows

    We test integrations against actual data volumes and edge cases, not just sample payloads, so the system holds up under real use.

  5. 05

    Deployment

    We roll out the integration in stages where possible, so existing workflows aren't disrupted.

  6. 06

    Monitoring

    We set up logging and alerts so failures are caught and handled before they affect your team or customers.

When companies come to us for API integration services

Systems that don't talk to each other. Your CRM, billing, and support tools each hold a piece of the picture, and someone on your team is copying data between them by hand. We build the API layer that removes that step.

A legacy system needs a modern API layer. Older platforms often lack a usable API, or expose one that's incomplete. We wrap legacy systems in a clean, documented API so modern tools can connect to them safely.

A SaaS product needs third-party integrations. Payments, CRM, analytics, and messaging providers all have their own APIs, and each one has its own quirks. We handle the integration work so your product ships on schedule.

Data needs to sync in real time across locations. When multiple offices, warehouses, or dealer sites need the same up-to-date information, batch syncs and manual exports aren't enough. We design real-time synchronization that keeps every location current.

The API management market keeps expanding

How fast is demand for structured API management growing? Fast. As companies rely on more connected systems, spending on API management is projected to grow sharply through the next decade.

$12.2B
$16.3B
$169.3B
202520262034

Global API management market size, 2025 to 2034 (projected). Source: Precedence Research

Integration platform spending is scaling up

Are companies still building one-off custom connections, or moving to structured integration platforms? Increasingly the latter. iPaaS market spending is projected to grow more than sixfold by 2034.

$15.6B
$19.2B
$108.8B
202520262034

Global iPaaS (integration platform as a service) market size, 2025 to 2034 (projected). Source: Fortune Business Insights

Frequently asked questions

What is included in API integration services?+

It covers designing or connecting to APIs, mapping data between systems, handling authentication and errors, and testing the integration against real data before it goes live.

How long does a typical API integration project take?+

It depends on the number of systems and how much cleanup the existing APIs need. A single third-party integration can take a few weeks. Connecting several systems, including a legacy one, takes longer.

Can you integrate with our existing ERP or legacy system?+

Yes. We've built ERP integrations before, including as part of a dealer management platform that ties ERP, telephony, and messenger systems together. If the legacy system lacks a usable API, we build a layer on top of it.

Do you build custom APIs or only connect existing ones?+

Both. If you need a new API for your own product, we design and build it. If you need to connect to APIs that already exist, we handle that integration work directly.

How do you handle API security and error handling?+

We implement proper authentication, rate limiting, and structured error handling, so failed requests are logged and retried safely instead of silently dropping data.

Do we need a full platform rebuild, or can you just connect our systems?+

Just connecting your systems is a standalone service we offer. Most of our integration work has been part of larger platform builds, but the same expertise applies to companies that only need their systems talking to each other.

Ready to connect your systems?

Tell us what needs to talk to what, and we'll scope the integration work without pushing a full rebuild you don't need.

  • Web Development

    Frontend, backend, CMS, and API work for production web platforms.

  • Mobile Development

    Native iOS/Android and cross-platform apps built for real users.

  • Custom Software Development

    Custom CRM, dealer management, and business software that runs real operations.

  • AI & Automation

    Automation and applied data/AI features integrated into real products.

  • SEO, AEO & GEO Optimization

    Technical SEO, structured data, and AI answer engine optimization built into your site.

  • MVP Development

    Fast, senior-built MVPs that stay solid enough to become the full product.

Shall we discuss your idea?
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Our offices

Lamana St. 18, 49000 Dnipro, Ukraine

C. de Bailén, 41, Centro, 28005 Madrid, Spain — ILab

Kamelia 47, 8240 Sunny Beach, Bulgaria — R&D office

Contacts

sales@leetsoft.dev
+380 73 758 17 72
+34 663 00 35 61