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Top RESTful APIs Companies

REST APIs dominate APIs: 83% of public APIs use REST, with the REST API management market rising from $5.42B to $32.77B by 2032 fueled by rapid enterprise adoption. Source: Amra and Elma LLC
RESTful APIs remain the foundation of modern software architecture, powering seamless communication between applications, services, and devices. By adhering to stateless principles and standard HTTP methods, REST APIs give developers flexibility, scalability, and broad ecosystem support. As businesses prioritize digital transformation, REST API development is a core strategy for microservices, cloud services, web apps, and mobile platforms. Whether you need custom backend integrations, API governance, or secure REST services, choosing the right developer or agency ensures high performance, strong documentation, and long-term scalability. This guide highlights leading RESTful API expertise, industry trends, and FAQs for selecting the best partner for your API initiatives.

 

List of the Best RESTful APIs Agencies | Top RESTful APIs Companies in the World

TheoremOne (previously Citrusbyte) is an innovation and engineering company that advises clients on product strategy, engineering, design, and culture, then partners with them to build and launch technology-driven solutions to their most complex problems. TheoremOne is chosen by clients when results matter most — becoming the agent of change, and driving a transformation that involves not only technology, but also… Read More
Building the world’s most potent IoT platform AT&T
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    Employees: 201 to 500
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    Min. Project amount: $25000
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    Country: USA

Synczer

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BUSINESS EXCELLENCE It is critical to select the greatest technology for your company's growth. Hiring an innovative IT services provider is the most straightforward approach to ensure that you are maximizing technology, increasing revenue, and staying ahead of the competition. PROGRESS To aid you in your role as a partner, we've collated your demands and awards to determine which can… Read More
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    Employees: 2 to 10
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    Min. Project amount: $25000
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    Country: USA
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    Employees: 2 to 10
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    Min. Project amount: $25000
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    Country: USA

Decurtis

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By focusing on these three pillars, DeCurtis can assist clients in increasing safety and security, driving new revenue streams and enhancing the overall guest experience. The DeCurtis Experience Platform™ powers all of our solutions and turns any indoor space into a location-aware environment aimed at increasing health and safety while efficiently transforming the guest experience. HEALTH, SAFETY & SECURITY DeCurtis… Read More
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    Employees: 51 to 200
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    Min. Project amount: $25000
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    Country: USA
We’re teachers, mentors, and seen‑it‑all‑beforers. Starting with your existing tools and practices, we make incremental improvements as you’re ready for them so that our process changes stick. Whatever issues you’re having with your software or your teams—we’ve likely seen them before, and we know how to solve them. Test Double agents are empathetic teachers and mentors, and we can’t wait to work with your team.… Read More
Test Double delivered a performance that in one case doubled our throughput . . . Steve continues to see around corners— identifying gaps in our architecture, proposing and implementing new approaches. I couldn’t imagine this project succeeding without his technical leadership. DAN CARROLL, CLEVER
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    Employees: 51 to 200
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    Min. Project amount: $25000
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    Country: USA

Senarios

5 (1)
Bring your ideas, we do the rest! Senarios is committed to provide exceptional software solutions and services for businesses, start-ups and enterprises. Bring in your ideas and we will help you build an empire. We provide custom software development services that helps in catalytic growth of your product. We know how to add the ‘X Factor’ in your business. Its… Read More
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    Employees: 11 to 50
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    Min. Project amount: $25000
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    Country: USA
OUR PHILOSOPHY Start Studio has been helping businesses design, build, market, and scale their flagship products since 2008. Creating new tech and helping our clients succeed is our passion. We've worked with some of the most successful companies in Utah, but we LOVE being plugged in with small startups as well. In order to stay on top of our game,… Read More
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    Employees: 0 to 1
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    Min. Project amount: $25000
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    Country: USA
For years, our co-founder Michael Girdley had been investing in startups in the local tech ecosystem. Over and over, he was approached by software company founders who were reaching out for investment and from others, a path to exit their businesses. But, there were no buyers that could provide the type of home these sellers wanted. ‍ These businesses were… Read More
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    Employees: 11 to 50
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    Min. Project amount: $25000
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    Country: USA

CSIntel

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A New Business (Program) Development Company - Here at CSIntel, it is our commitment to you that makes us strong. We believe that a business is only as successful as its clientele. Thus, we founded CSIntel on the philosophy of providing an affordable, cutting-edge solution for companies to be able to compete in today's fast-paced technological world. So it is… Read More
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    Employees: 2 to 10
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    Min. Project amount: $25000
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    Country: USA
We partner with early stage founders to deliver a turnkey solution from ideation to product implementation. We work with a team of experts at each product development phase to bring a product from concept to reality, developing a high-quality application that meets requirements and delivers results. Founders in the very early idea stage may engage in our design thinking workshops… Read More
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    Employees: 2 to 10
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    Min. Project amount: $25000
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    Country: USA

** Buyer's Guide **

1.What services do RESTful API developers or agencies provide?

They design and build stateless, scalable REST APIs, handle API documentation & testing, integrate with backend systems, implement authentication/security, and support deployment & monitoring.

RESTful API developers or agencies provide a wide range of services centered around the design, development, deployment, and maintenance of RESTful APIs. Their offerings typically include:

1. API Design & Architecture

  • Designing API endpoints, data models, and request/response structures following RESTful principles.
  • Defining authentication and authorization mechanisms (e.g., OAuth, JWT).
  • Creating API documentation and specifications (often using OpenAPI/Swagger).
  • Ensuring scalability, security, and maintainability in the API architecture.

2. API Development

  • Implementing API endpoints using popular frameworks and programming languages (such as Node.js, Python, Java, Ruby, or PHP).
  • Integrating APIs with databases, third-party services, or other internal systems.
  • Handling versioning, error handling, and response formatting.

3. API Integration

  • Connecting client applications (web, mobile, IoT) to APIs.
  • Facilitating integration with external APIs, SaaS products, or legacy systems.
  • Providing SDKs or client libraries for easier API consumption.

4. Testing & Quality Assurance

  • Writing unit, integration, and end-to-end tests for API endpoints.
  • Performing load testing and performance optimization.
  • Ensuring compliance with security best practices (e.g., input validation, rate limiting).

5. API Documentation & Developer Experience

  • Creating clear, interactive documentation for developers (using Swagger, Postman, Redoc, etc.).
  • Providing API usage guides, code samples, and onboarding support.

6. Deployment & DevOps

  • Setting up API hosting environments (cloud platforms, on-premises, serverless).
  • Managing CI/CD pipelines for API deployment and updates.
  • Configuring monitoring, logging, and alerting for production APIs.

7. API Maintenance & Support

  • Ongoing monitoring and debugging of API issues.
  • Applying security patches, performance improvements, and new features.
  • Managing API deprecation and migration strategies.

8. Consulting & Advisory

  • Reviewing existing APIs for best practices, performance, and security.
  • Advising on API strategy, monetization, and digital transformation initiatives.
  • Training internal teams on API design, usage, and management.

In summary, RESTful API developers or agencies act as end-to-end partners for organizations looking to expose, consume, or manage APIs, ensuring robust, secure, and scalable digital integrations.

2.Should I hire a REST API specialist developer or an agency?

Choose individual developers for lean/short-term builds or smaller projects; agencies are ideal for complex, enterprise-grade API ecosystems with broader technical needs.

RESTful API developers or agencies provide a wide range of services centered around the design, development, deployment, and maintenance of RESTful APIs. Their offerings typically include:

1. API Design & Architecture

  • Designing API endpoints, data models, and request/response structures following RESTful principles.
  • Defining authentication and authorization mechanisms (e.g., OAuth, JWT).
  • Creating API documentation and specifications (often using OpenAPI/Swagger).
  • Ensuring scalability, security, and maintainability in the API architecture.

2. API Development

  • Implementing API endpoints using popular frameworks and programming languages (such as Node.js, Python, Java, Ruby, or PHP).
  • Integrating APIs with databases, third-party services, or other internal systems.
  • Handling versioning, error handling, and response formatting.

3. API Integration

  • Connecting client applications (web, mobile, IoT) to APIs.
  • Facilitating integration with external APIs, SaaS products, or legacy systems.
  • Providing SDKs or client libraries for easier API consumption.

4. Testing & Quality Assurance

  • Writing unit, integration, and end-to-end tests for API endpoints.
  • Performing load testing and performance optimization.
  • Ensuring compliance with security best practices (e.g., input validation, rate limiting).

5. API Documentation & Developer Experience

  • Creating clear, interactive documentation for developers (using Swagger, Postman, Redoc, etc.).
  • Providing API usage guides, code samples, and onboarding support.

6. Deployment & DevOps

  • Setting up API hosting environments (cloud platforms, on-premises, serverless).
  • Managing CI/CD pipelines for API deployment and updates.
  • Configuring monitoring, logging, and alerting for production APIs.

7. API Maintenance & Support

  • Ongoing monitoring and debugging of API issues.
  • Applying security patches, performance improvements, and new features.
  • Managing API deprecation and migration strategies.

8. Consulting & Advisory

  • Reviewing existing APIs for best practices, performance, and security.
  • Advising on API strategy, monetization, and digital transformation initiatives.
  • Training internal teams on API design, usage, and management.

In summary, RESTful API developers or agencies act as end-to-end partners for organizations looking to expose, consume, or manage APIs, ensuring robust, secure, and scalable digital integrations.

Should I hire a REST API specialist developer or an agency? Choose individual developers for lean/short-term builds or smaller projects; agencies are ideal for complex, enterprise-grade API ecosystems with broader technical needs.

When deciding between hiring a REST API specialist developer or an agency, consider the scale, complexity, and long-term needs of your project:

Choose an individual developer if:

  • Your project is lean, short-term, or focused on a single, well-defined API.
  • You have a limited budget and want a cost-effective solution.
  • Your technical requirements are straightforward, and you can manage project oversight directly.
  • You need rapid prototyping or a quick MVP (Minimum Viable Product).

Choose an agency if:

  • Your project is complex, large-scale, or enterprise-grade, requiring robust architecture and scalability.
  • You need a team with diverse skills (e.g., design, development, QA, DevOps, security).
  • You expect ongoing support, maintenance, or integration with other systems.
  • You want comprehensive services, from strategy and consulting to deployment and documentation.
  • Project management, risk mitigation, and adherence to best practices are priorities.

Summary:
Go with an individual developer for smaller, focused, or short-term builds. Opt for an agency when your REST API needs are part of a broader, more complex technical ecosystem requiring multidisciplinary expertise and long-term support.

3.What technologies do top REST API developers use?

Common stacks include Node.js/Express, Python (Django/Flask), Java/Spring Boot, Go, and REST API tools like Postman and OpenAPI/Swagger for specs.

Top REST API developers utilize a range of technologies, tools, and best practices to design, build, test, and maintain high-quality APIs. Here’s an overview of the core technologies and approaches commonly used:

1. Programming Languages & Frameworks

  • JavaScript (Node.js/Express.js): Widely used for its asynchronous capabilities and vast ecosystem.
  • Python (Django REST Framework, Flask): Popular for rapid development and robust community support.
  • Java (Spring Boot): Enterprise-grade APIs with powerful tooling and scalability.
  • Go (Gin, Echo): Chosen for high performance and simplicity in concurrency.
  • Ruby (Rails – with built-in API support): Quick prototyping and developer productivity.
  • .NET (ASP.NET Core): Strong in enterprise and Windows-centric environments.

2. API Specification & Documentation

  • OpenAPI (Swagger): Standard for describing RESTful APIs, enabling auto-generation of docs, clients, and server stubs.
  • Postman Collections: For interactive API documentation and sharing.
  • Redoc: For visually appealing and interactive documentation based on OpenAPI.

3. Data Formats

  • JSON: Default choice for API payloads due to simplicity and ubiquity.
  • XML: Still used in legacy or enterprise contexts.
  • YAML: Sometimes used for configuration, rarely for payloads.

4. Authentication & Security

  • OAuth 2.0 / OpenID Connect: Standard for delegated authorization.
  • JWT (JSON Web Tokens): For stateless authentication.
  • API Keys: Simple, but less secure; often used for internal or less sensitive APIs.
  • HTTPS (TLS): Mandatory for encrypting API traffic.

5. Testing & Debugging Tools

  • Postman: Popular for manual API testing and automation.
  • Insomnia: Another user-friendly API client.
  • curl/HTTPie: Command-line tools for quick API calls.
  • Automated Testing Frameworks: Jest (JS), Pytest (Python), JUnit (Java), etc.

6. Monitoring & Logging

  • API Gateways: Kong, AWS API Gateway, Apigee – for rate limiting, analytics, and security.
  • Logging Tools: ELK Stack (Elasticsearch, Logstash, Kibana), Splunk.
  • APM (Application Performance Monitoring): New Relic, Datadog.

7. DevOps & Deployment

  • Containerization: Docker for consistent deployment environments.
  • Orchestration: Kubernetes for scaling and managing microservices.
  • CI/CD Pipelines: Jenkins, GitHub Actions, GitLab CI for automated testing and deployment.

8. Versioning & Best Practices

  • URI Versioning: e.g., /api/v1/resource
  • Semantic Versioning: For backward compatibility.
  • Rate Limiting: To prevent abuse.
  • CORS Management: For cross-origin requests.

Summary

Top REST API developers combine robust programming frameworks, open standards for documentation, secure authentication methods, and modern DevOps practices. They leverage both manual and automated tools for testing, maintain clear versioning, and prioritize security and performance monitoring throughout the API lifecycle. This ecosystem allows for scalable, maintainable, and secure REST APIs.

4.How much does hiring a REST API developer or agency cost?

The cost of hiring a REST API developer or agency depends on several factors, including the developer’s location, experience, project complexity, and whether you work with a freelancer or a professional agency. Here’s a more detailed breakdown:

1. Freelance REST API Developers

  • Entry-level: $20–$40/hr (often overseas or early-career developers)
  • Mid-level: $40–$75/hr (developers with several years’ experience, good portfolio)
  • Senior/Expert: $75–$150/hr+ (specialized skills, high-demand locations, or niche expertise)

Freelancers can also work on a fixed-price basis, with simple APIs starting at a few hundred dollars and complex, production-grade APIs costing several thousand dollars.

2. REST API Development Agencies

  • Small/Regional Agencies: $75–$150/hr
  • Established or Specialized Agencies: $150–$250/hr+
  • Top-tier/Enterprise Agencies: $250/hr and up

Agencies typically estimate costs based on project requirements, and may provide a fixed project quote. For reference:

  • Simple API (single resource, basic CRUD): $2,000–$10,000
  • Medium API (multiple resources, authentication, documentation): $10,000–$30,000
  • Complex API (integrations, scalability, security, analytics): $30,000–$100,000+

3. Additional Factors Affecting Cost

  • Project Scope: More endpoints, integrations, and features increase cost.
  • Security and Compliance: APIs requiring advanced security, compliance (GDPR, HIPAA, etc.) are more expensive.
  • Maintenance & Support: Ongoing costs for updates, bug fixes, and enhancements.
  • Location: Developers in North America and Western Europe bill higher than those in Asia, Eastern Europe, or Latin America.

Summary

  • Freelancers: ~$25/hr to $150/hr+, or $2,000–$10,000+ for a project.
  • Agencies: $75/hr to $250/hr+, or $10,000–$100,000+ for complex APIs.

For the best results, define your project scope and requirements clearly before seeking quotes, and always review portfolios, references, and technical proficiency.

Costs vary widely: freelance developers often start ~$25/hr+, while experienced agency teams generally bill higher based on project scope and expertise. 

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