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

Celadonsoft
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We assist expanding businesses in developing scalable operational platforms, business systems, and AI-driven workflows tailored for integration-heavy and complex operational settings. Why choose Celadonsoft? We begin with discovery, solution design, and business analysis to define the architecture,
Highlights
$10,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
50-249
Employees
Warszawa, Masovian, Pl
Services Provided+3 Services
25% Custom Web Application Development
10% Mobile App Development (iOS & Android)
15% API Development & Integration
15% AI Strategy & Roadmap Consulting
AI Summary
“Celadonsoft develops scalable, AI-driven operational platforms and complex systems for growing businesses, specializing in integration-heavy workflows across Food & Beverage, Real Estate, and FinTech sectors.”
Zavod-IT
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Zavod-IT focuses on creating startups, intricate software solutions, mobile apps, websites, and APIs for third-party systems. Our team possesses extensive experience in building websites, e-commerce platforms, cashback services, Telegram bots, and cryptocurrency exchanges. With over 12 years in the
Highlights
$1,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
10-49
Employees
San Francisco, California, Us
Services Provided+5 Services
20% Machine Learning Model Development
20% API Development & Integration
15% Blockchain & Web3 Development
10% Software Development Services
AI Summary
“Zavod-IT specializes in comprehensive software development, including API integration, blockchain projects, custom web applications, e-commerce platforms, and mobile app development, showcasing their strong capabilities and extensive industry experience in these areas.”
PRIOT
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We revolutionize businesses through all-encompassing digital solutions and innovative approaches. Our projects cover the entire process, from initial design to final implementation, with a strong emphasis on delivering an outstanding user experience. Our competitive edge lies in: 1. Engaging early i
Highlights
$50,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
2-9
Employees
Maribor, Si
Services Provided+2 Services
35% Custom Web Application Development
15% API Development & Integration
20% Product UX Strategy
10% Mobile App UI Design
AI Summary
“PRIOT delivers comprehensive digital solutions combining custom software development, robust API integration, and user-centered UX/UI design, leveraging modern technologies and agile methods for scalable, innovative products.”
CWS Platform
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The CWS Platform is a B2B commerce infrastructure built with AI at its core, designed to allow AI agents to manage entire commercial cycles with customizable autonomy, while strictly following the business rules embedded in your existing ERP and CRM systems. It serves as a vital orchestration layer
Highlights
$50,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
50-249
Employees
Sao Paulo, Sao Paulo, Br
Services Provided
50% AI Agent & Multi-Agent System Development
35% E-Commerce Development
15% API Development & Integration
AI Summary
“CWS Platform integrates AI-driven agents with ERP/CRM systems, ensuring deterministic business rule enforcement for secure, efficient, and autonomous B2B commercial cycle management.”
GigLabo
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At our development agency, we specialize in transforming ideas into exceptional software. We cater to startups, entrepreneurs, and business leaders who require tailored software solutions that perfectly align with their objectives. Whether you need a straightforward app to launch your startup, sophi
Highlights
$1,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
2-9
Employees
Munich, Bavaria, De
Services Provided
35% Custom Web Application Development
15% API Development & Integration
50% Machine Learning Model Development
AI Summary
“GigLabo is a development agency specializing in custom software, AI integration, and MVP creation, collaborating closely with clients to deliver user-friendly, impactful technology solutions.”
Almondai Technologies
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AlmondAI Technologies is an innovative AI firm revolutionizing various sectors with state-of-the-art solutions. We focus on Vision-Language Models (VLLMs), Generative AI, Computer Vision, and systems based on machine learning and deep learning. Our groundbreaking tools, such as sophisticated video s
Highlights
$1,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
10-49
Employees
Services Provided+3 Services
15% Generative AI
15% Machine Learning Model Development
5% Custom AI Chatbot Development
5% AI Strategy & Roadmap Consulting
AI Summary
“AlmondAI Technologies develops advanced AI solutions including vision-language models and generative AI, enhancing efficiency across education, retail, automation, and manufacturing sectors.”
Cebrian IT
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Tailored Software Development. I turn concepts into reliable and enduring technology solutions, with over 20 years of experience creating lasting software for essential industries.
Highlights
$5,000+
Min Project Size
$50-99/hr
Avg Hourly Rate
Grepiac, Fr
Services Provided
15% Mobile App Development (iOS & Android)
18% API Development & Integration
17% Custom Web Application Development
50% ERP Consulting and SI
AI Summary
“Cebrian IT specializes in tailored software development, leveraging over 20 years of experience to deliver reliable, enduring technology solutions across essential industries.”
Sheraian Limited
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Sheraian Limited is a results-oriented mobile app development firm that assists mid-sized businesses in creating scalable, high-performance applications that promote significant growth. We collaborate with companies throughout the UK, Europe, and worldwide from the initial concept to the final launc
Highlights
$1,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
2-9
Employees
Gujrat, Pk
Services Provided
10% Custom Web Application Development
70% Mobile App Development (iOS & Android)
15% API Development & Integration
5% E-Commerce Development
AI Summary
“Sheraian Limited is a mobile app development firm delivering scalable, user-centric iOS and Android solutions for mid-sized businesses worldwide, emphasizing collaboration and reliable, growth-oriented applications.”
JetBase.IO
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We assist founders and product leaders in developing, launching, and scaling software, from the initial MVP to long-term product expansion. With over 60 projects completed and 4 products successfully exited, we act as an integral part of your team. You can concentrate on strategy and growth while we
Highlights
$5,000+
Min Project Size
$25-49/hr
Avg Hourly Rate
10-49
Employees
Sheridan, Wyoming, Us
Services Provided+2 Services
15% API Development & Integration
15% Mobile App Development (iOS & Android)
15% Custom Web Application Development
5% E-Commerce Development
AI Summary
“JetBase.IO partners with founders and product leaders to develop and scale software across diverse industries, managing engineering and delivery using technologies like React, AWS, and Python.”
Ontoborn Technologies
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Ontoborn is a small group of software engineers united by a shared enthusiasm for computer science. We create top-notch software solutions for businesses, investment companies, startups, and researchers. We tackle all sorts of unconventional projects that others often decline. Our portfolio includes
Highlights
$100,000+
Min Project Size
< $25/hr
Avg Hourly Rate
2-9
Employees
Columbus, Ohio, Us
Services Provided+1 Services
20% AI Strategy & Roadmap Consulting
30% AI Agent & Multi-Agent System Development
15% API Development & Integration
15% Mobile App Development (iOS & Android)
AI Summary
“Ontoborn Technologies is a skilled software engineering team delivering diverse solutions including AI models, applications, embedded systems, and data analytics, partnering with academia and industry for complex projects.”

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Top API Development & Integration Firms

List of the Best API Development & Integration Agencies

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