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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We evaluate companies on verified profile data: services, pricing, locations, and portfolio. Client reviews are being collected. We may earn a fee for some placements. How we rank and verify

8,490 Companies

List of the Best API Development & Integration Agencies

Messy Programmer
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Messy Programmer is your reliable ally for high-quality IT services at reasonable rates. Prioritizing both excellence and cost-effectiveness, we offer a variety of IT solutions specifically designed to cater to your business requirements.
Highlights
$1,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
2-9
Employees
Services Provided
70% Custom Web Application Development
30% API Development & Integration
AI Summary
“Messy Programmer delivers high-quality, cost-effective IT services tailored to diverse business needs, combining professionalism and reliability to support your technology goals effectively.”
Qloter Tekno Data
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Qloter is a tech firm dedicated to creating ERP systems tailored for small businesses. We recognize that numerous small and mid-sized companies struggle with integrating the management of finances, inventory, and operations. Issues such as reliance on manual processes, scattered record-keeping, and
Highlights
$5,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
2-9
Employees
East Jakarta, Jakarta, Id
Services Provided
60% Custom Web Application Development
30% API Development & Integration
10% E-Commerce Development
AI Summary
“Qloter Tekno Data develops tailored ERP solutions for small businesses, enabling integrated management of finances, inventory, and operations, enhancing efficiency and supporting digital transformation.”
Vstellar
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Accelerate your testing procedures using Stellar's low-code automation platform. Improve efficiency, reduce errors, and achieve more intelligent software testing through seamless solutions for UI, API, mobile, performance, and accessibility testing. Equip your team to conduct more tests with less st
Highlights
$1,000+
Min Project Size
2-9
Employees
Services Provided
30% API Development & Integration
70% QA & Software Testing
AI Summary
“Vstellar offers a low-code automation platform enhancing software testing efficiency across UI, API, mobile, performance, and accessibility with seamless integration and advanced analytics.”
Spenza
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Spenza is a connectivity enablement platform that is neutral to operators, designed for businesses. It provides procure-to-pay SaaS solutions along with an integrated marketplace for mobile plans, helping companies manage their wireless expenses and streamline their operations. Spenza includes APIs,
Highlights
10-49
Employees
Services Provided
70% SaaS Product Development
30% API Development & Integration
AI Summary
“Spenza offers a neutral connectivity platform with SaaS solutions and an integrated marketplace, enabling businesses to manage wireless expenses, streamline operations, and deliver tailored cellular services to end users.”
OneNotary
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OneNotary is the premier provider of online notarization in the U.S., available 24/7 and endorsed by major companies like DocuSign, Morgan Stanley, Liberty Mutual, Amazon, DoorDash, Procore, and countless others. We facilitate connections to a trained notary within a minute, with most notarizations
Highlights
10-49
Employees
San Francisco, California, Us
Services Provided
80% Litigation
20% API Development & Integration
AI Summary
“OneNotary delivers enterprise-grade online notarization across the U.S., providing fast, compliant, and scalable services endorsed by major corporations for seamless business integration.”
SC ELISIUM TECH SRL
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Elisium Tech is a web and cloud development agency focused on delivering results with speed, scalability, and reliability. We assist rapidly growing companies in producing higher-quality products more quickly. Our services range from custom builds using Laravel, Nest/Node.js, and Vue.js to intricate
Highlights
$1,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
2-9
Employees
Oradea, Bihor, Ro
Services Provided
60% Custom Web Application Development
30% API Development & Integration
10% E-Commerce Development
AI Summary
“SC ELISIUM TECH SRL is a web and cloud development agency delivering scalable, reliable custom solutions with cutting-edge technologies, combining technical expertise and business focus for rapid, high-quality product outcomes.”
81 Degrees, LLC
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81 Degrees is a comprehensive software engineering agency that converts visionary concepts into fully developed digital products ready for the market. We collaborate with startups, large enterprises, and innovators to manage every aspect of the software development lifecycle—from the initial idea an
Highlights
$5,000+
Min Project Size
2-9
Employees
DeLand, Florida, Us
Services Provided
34% API Development & Integration
33% Cloud Consulting & SI
33% DevOps Engineering
AI Summary
“81 Degrees is a software engineering agency delivering end-to-end digital product solutions—encompassing ideation, design, development, deployment, and support—for startups and enterprises alike.”
SO Management
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We utilize the Symfony Framework for web development and OpenCart for building our eShop. Additionally, we create ERP solutions and payment integrations.
Highlights
$25-49/hr
Avg Hourly Rate
2-9
Employees
Samokov, Bg
Services Provided
34% API Development & Integration
33% ERP Consulting and SI
33% Social Media Marketing
AI Summary
“SO Management specializes in web development using Symfony Framework, e-commerce solutions with OpenCart, and offers ERP system development alongside payment integration services.”
InfoSwift
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Infoswift provides comprehensive digital transformation and IT services throughout the United States. We specialize in cloud solutions, artificial intelligence, app modernization, and enterprise services. Schedule a complimentary consultation. As a technology partner based in the US, Infoswift helps
Highlights
50-249
Employees
Services Provided
33% API Development & Integration
20% Robotic Process Automation (RPA)
14% Custom AI Chatbot Development
33% Data Annotation Services
AI Summary
“InfoSwift is a US-based technology partner specializing in cloud solutions, AI, app modernization, and enterprise services, enabling organizations to accelerate digital transformation nationwide.”
Skytech Cyber Cloud
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SkyTech, a digital transformation firm based in London and Dubai, provides a wide range of services designed to meet the needs of its expanding client base, utilizing cutting-edge technologies such as Intelligent Automation (IA), Artificial Intelligence (AI), and Robotic Process Automation (RPA). We
Highlights
$5,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
10-49
Employees
Dubai, Dubayy, Ae
Services Provided
33% API Development & Integration
33% Brand Identity Design
20% Search Engine Optimization (SEO)
14% Social Media Marketing
AI Summary
“SkyTech is a London and Dubai-based digital transformation firm specializing in Intelligent Automation, AI, and RPA, enhancing clients' digital environments through innovative, collaborative solutions.”

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Top API Development & Integration Firms

List of the Best API Development & Integration Agencies

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