Top API Development & Integration Firms

API development and integration firms build the interfaces that let software talk to other software, and wire up the ones that already exist. Work ranges from designing REST, GraphQL or gRPC APIs for a product or partner program to connecting payment gateways, CRMs, ERPs, shipping carriers, messaging platforms and banking or healthcare systems through their published APIs. Companies hire for it when staff retype data between two systems, when partners want programmatic access, or when a monolith is being split into services.

Compare firms here on the systems they have integrated before, the documentation they hand over, and how they handle authentication, versioning and outages when a third-party API fails.

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8,490 Companies

List of the Best API Development & Integration Agencies

Task4IT
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WordPress Development Agency specializing in custom WP Theme creation. Our talented team operates out of Lisbon and London, collaborating with startups, digital agencies, and established businesses. We focus on innovative WordPress solutions, crafting corporate themes from the ground up that are fle
Highlights
$5,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
2-9
Employees
Lisboa, Lisbon, Pt
Services Provided
40% E-Commerce Development
30% API Development & Integration
30% Custom Web Application Development
AI Summary
“Task4IT is a WordPress development agency specializing in custom themes, leveraging modern technologies to provide scalable, tailored digital solutions for startups and established businesses.”
TopFlight Digital
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TopFlight enhances the experimentation process for product and tech teams. We excel in creating and implementing A/B tests and feature experiments, guiding organizations away from assumption-driven approaches and fostering in-house technical skills and maturity. Our emphasis is on rapid testing and
Highlights
$10,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
10-49
Employees
Burnley, England, Gb
Services Provided
30% Custom Web Application Development
30% API Development & Integration
10% Legacy System Modernization
30% QA & Software Testing
AI Summary
“TopFlight Digital specializes in enhancing experimentation for product teams by implementing A/B and feature tests, enabling rapid, data-driven decisions and developing in-house technical expertise across major platforms.”
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Salitronic
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I create comprehensive electronic systems, transitioning from initial concept to production-ready hardware, leveraging over 20 years of experience with a significant emphasis on reliability, manufacturability, and real-world performance. My services cater to individuals, startups, research teams, an
Highlights
Services Provided
13% Custom Web Application Development
37% API Development & Integration
50% Product Design
AI Summary
“Salitronic offers end-to-end electronic system design and development services, combining 20+ years' expertise in hardware, embedded firmware, prototyping, and manufacturing support to ensure reliable, manufacturable products.”
Purple Software
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Purple Software develops tailor-made intelligent software and AI-driven digital assistants that prevent operational failures, allowing you to concentrate on what really counts. Our systems provide liberation: liberation from disorder, repetitive tasks, and unreliable processes. We do not substitute
Highlights
$50-99/hr
Avg Hourly Rate
10-49
Employees
Colombo, Western Province, Lk
Services Provided
45% Custom Web Application Development
15% Mobile App Development (iOS & Android)
10% E-Commerce Development
30% API Development & Integration
AI Summary
“Purple Software creates custom intelligent software and AI-driven assistants that streamline operations, reduce errors, and enhance human productivity by eliminating repetitive and unreliable tasks.”
Fronseye Technologies
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We are an ambitious team focused on developing custom software solutions for businesses of all sizes. Our company, founded by individuals with IT expertise, excels in delivering high-quality, unique web solutions through innovative strategies that help our clients accelerate their time to market. We
Highlights
$5,000+
Min Project Size
< $25/hr
Avg Hourly Rate
10-49
Employees
Chennai, Tamil Nadu, In
Services Provided
50% Custom Web Application Development
15% Mobile App Development (iOS & Android)
25% API Development & Integration
10% E-Commerce Development
AI Summary
“Fronseye Technologies develops custom web and mobile software solutions, including ERP and CRM apps, leveraging diverse tech stacks to serve various industries with scalable, high-quality products.”
Polcode
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At Polcode, we are committed to providing valuable software solutions. As a software development and IT consulting firm, we assist businesses in designing, developing, and scaling digital products that drive growth. Since our inception in 2006, we have collaborated with organizations in the US and E
Highlights
$10,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
50-249
Employees
Warszawa, Masovian, Pl
Services Provided
15% E-Commerce Development
50% Custom Web Application Development
25% API Development & Integration
10% Legacy System Modernization
AI Summary
“Polcode is a software development and IT consulting firm providing custom applications, product design, and managed IT services, delivering scalable solutions across healthcare, fintech, retail, and more since 2006.”
Differenz System
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At Differenz System, we concentrate on delivering a wide range of web and app development solutions that enhance our clients' productivity and profitability. Our company is founded on three key principles: exceptional performance, high productivity, and a vibrant, energizing work atmosphere. Our te
Highlights
$5,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
50-249
Employees
Los Angeles, California, Us
Services Provided
40% Custom Web Application Development
35% Mobile App Development (iOS & Android)
25% API Development & Integration
AI Summary
“Differenz System specializes in custom web and mobile app development, delivering innovative software solutions across industries to boost productivity and client profitability.”
Giraffe Studio
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We develop mobile and web applications, websites, e-commerce platforms, content management systems (CMS), customer relationship management (CRM) solutions, APIs, and handle UX and UI design. Our goal is to deliver comprehensive products characterized by exceptional design, high usability, and intuit
Highlights
$5,000+
Min Project Size
< $25/hr
Avg Hourly Rate
10-49
Employees
Krakow, Lesser Poland, Pl
Services Provided
40% Custom Web Application Development
25% API Development & Integration
35% Mobile App Development (iOS & Android)
AI Summary
“Giraffe Studio is a versatile IT company delivering customized web and mobile applications, e-commerce, CMS, and CRM solutions worldwide, emphasizing exceptional design, usability, and timely, budget-conscious delivery.”
Migosys
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Migosys assists expanding companies in streamlining workflows, integrating systems, and driving growth with personalized technology solutions. We focus on linking separate tools, removing tedious manual tasks, and enhancing CRM platforms such as HubSpot and Salesforce. Whether you require custom API
Highlights
$1,000+
Min Project Size
< $25/hr
Avg Hourly Rate
2-9
Employees
Services Provided
24% CRM Consulting and SI
10% Cloud Consulting & SI
33% API Development & Integration
33% Product UX Strategy
AI Summary
“Migosys delivers customized technology solutions that streamline workflows, integrate systems, automate tasks, and optimize CRM platforms like HubSpot and Salesforce to support scalable business growth.”
Sanbi Ai
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Sanbi delivers essential infrastructure for monitoring AI visibility and brand assessment. With the transition in search behavior from conventional links to AI-generated responses, we provide businesses with the tools necessary to monitor, analyze, and enhance their visibility on Large Language Mode
Highlights
$1,000+
Min Project Size
$100-149/hr
Avg Hourly Rate
2-9
Employees
Dallas, Texas, Us
Services Provided+1 Services
7% AI Agent & Multi-Agent System Development
10% Custom AI Chatbot Development
17% AI Strategy & Roadmap Consulting
33% API Development & Integration
AI Summary
“Sanbi provides infrastructure and tools for monitoring and optimizing brand visibility on AI-driven search platforms, enabling businesses to analyze performance and enhance positioning against competitors.”

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Top API Development & Integration Firms

List of the Best API Development & Integration Agencies

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