What Are the Top Unified APIs?

The top unified APIs are Nango, Merge, Apideck, Unified.to, and Paragon. Nango fits engineer-heavy teams that want open-source and the most connectors; Merge suits enterprises focused on HR, accounting, and CRM; Apideck works as a broad, easy starting point; Unified.to is built for data privacy and real-time results; and Paragon fits B2B SaaS teams that need a white-labeled, embeddable experience with multi-tenant MCP support for AI agents.

Suppose that your organization uses multiple storage platforms including Google Drive, DropBox, and AWS buckets. You could manage code for all three platforms, or you could use a unified API that works with all three platforms for you. A unified API can connect your applications to hundreds of other SaaS tools. Developers manage code for a single endpoint on the unified platform API, and the unified API handles the rest, including OAuth authentication for your users.

We won’t go too far into the basic details for unified APIs, because we covered the basics of unified APIs already. This article will focus on the top unified APIs on the market and the pros and cons for each vendor to help you decide on what’s best for you.

Overview of the Top Unified APIs

This article will talk about five top unified APIs, including Nango, Merge, Apideck, Unified.to and Paragon. Here is a brief overview of all five for a TLDR of each vendor.

Nango

Nango is the best for engineer-heavy businesses where high customizations and code control are a concern. It’s open-source and supports over 800 APIs across several categories including CRM, ERP, accounting, e-commerce, email, and documents. It offers the most connectors of all the vendors. If you’re a developer and want to work with open-source, Nango is a good option.

Merge

For a more generalized approach, Merge has unification for six categories and 220 integrations. Merge works by first importing data to its platform and then letting you query their platform for data, which improves performance but limits real-time data analysis. Because it’s made for enterprise, Merge has a high rate limit for a large volume of queries. Merge is best for enterprises focused on HR, accounting, and CRM integrations.

Apideck

Apideck has a wider range of connectors compared to Nango and Merge. Developers can use Apideck’s SDKs to integrate the unified API directly into their software without writing code from scratch. Apideck is a good “starter” for unified API integration, but it can often lack features when businesses have edge-case scenarios. Use Apideck if you are new to unified APIs and don’t have many business use cases for them yet.

Unified.to

For businesses concerned with privacy, Unified.to does not store any data. When an API call is made, data passes through Unified.to proxies without being cached. This is great for privacy, but it could harm performance. Because there is no caching, data and queries are presented in real-time. Unified.to is best for businesses concerned with data privacy and a need for real-time data results.

Paragon

Paragon is a B2B SaaS platform (specifically, an iPaaS, or integration Platform as a Service) that solves business problems when their core features depend on multiple APIs. Paragon focuses on enterprise operations where edge cases, customization, and a complete developer experience are necessary including observability, whitelabeling, AI-based analysis, customizations, and a wide range of category integrations. It has a friendly drag-and-drop user interface making it easier for non-developers as well. It also had an on-premise option for businesses concerned about where they are hosting their data (data privacy). Paragon is best for B2B businesses or agencies that need scalability, AI solutions, and want to white label a solution with a user-friendly interface for their customers.

Comparison Table for Unified APIs

If you’re looking for a quick comparison between Merge, Nango, Apideck, Unified.to, and Paragon, the following table is for you. The MCP row is especially useful for businesses that want to make calls to APIs using AI agents.

How Unified APIs Work

The general purpose of a unified API is the same: make it easier for developers and businesses to offer a wide range of third-party productivity software in a single interface without the need for managing multiple APIs and vendors in their code. This is true for any unified API, but the way each vendor does it varies.

The connectors or integrations you’ll see each vendor mention are the third-party APIs they offer. For example, if you need to implement Salesforce, Hubspot, and Zendesk into an application, the unified API vendor you choose must have a connector (or integration) for these three services.

Another example is communication. It’s not uncommon for businesses to have multiple communication platforms like Microsoft Teams, Slack, and Zoom. You need a unified API that supports these three services as well. To save yourself a lot of frustrations, the first step in choosing a vendor is ensuring that they support your business development workflow.

The workflow for connecting to the unified API can be summarized as:

• Authenticate into the unified API

• Use OAuth to connect to the third-party business application (e.g., Salesforce and Hubspot)

• Unified API stores and handles OAuth tokens and refresh tokens

• Developer writes code to make a call to the unified API

• Unified API retrieves the call from your main application and sends a query to the third-party application on behalf of the user using OAuth tokens.

• Unified API retrieves data from the third party and organizes it into a standard schema

• Developer can use the expected schema data to then show information to the user

Where vendors diverge is in the architecture and the way that they handle queries and data management. For example, Merge periodically pulls data from various third-party applications and stores it on their local infrastructure. They call it a “sync and cache” method. This makes Merge fast and offers low latency when users query platforms for data, but it also means the data could be stale. Stale data isn’t optimal for businesses that need real-time (or close to real-time) information, like the finance industry.

Unified.to solves the stale data issue and does not store it in local cache, which means customers get real-time data results. The downside is that performance might suffer since every query requires a new call to the third-party application platforms.

Nango and Apideck focus more on breadth of integrations and levels of abstraction. Nango has less abstraction, which means that your developers have much more control over integrations. Less abstraction exposes flexibility for customizations, but it’s much more complex and requires more research and (likely) testing to flesh out bugs. More abstraction hides complexity, so it’s easier for developers to get up to speed, understand endpoints, and integrate faster. In a nutshell: abstraction hides complexity, so there is a lower barrier to entry.

Apideck is more abstract, so the complexity behind integrations is hidden and offers convenience to developers. Abstraction is a tradeoff, and the trade benefits depend on your use case. More abstraction means that your developers can code more quickly without the learning curve. Less abstractions give more control back to the developer, but add complexity. Nango and Apideck are great for code-first environments, but you need to decide if you want full control (Nango) or more abstraction and convenience (Apideck).

Paragon takes integrations a step further and lets your customers add integrations without requiring overhead from a developer. Users choose from dozens of connectors where they can connect their account to the local application using a graphical-friendly interface. Paragon offers the basic integration and abstraction that the other vendors offer, but they also have a list of connectors that customers can choose from and connect without dealing with complicated configuration pages with traditional applications.

What makes unified APIs beneficial to businesses is that most of the behind-the-scenes architecture and code are completely invisible to the developer and users of your applications. A unified API handles the complexity of OAuth, managing tokens, endpoint queries, and data processing and packages it into a schema that developers can use. Their benefit is in data organization and simplifying your coding workflows.

Model Context Protocol (MCP) Handling for AI

Businesses focused on building AI agents and AI integration should focus on MCP, or model context protocol. With AI agents taking over for many common tasks across industries, these agents need a way to call the various platforms integrated into productivity workflows. Unified APIs handle this process using MCPs.

MCP is a standard introduced by Anthropic. Before MCP, developers and data scientists had to create their own data schemas and standards, and these standards were often proprietary. Every new implementation needed another data standard. Think of MCP as the JSON of the AI integration industry. It’s a standard that allows applications to expect a specific format when communicating with unified API endpoints.

Unified APIs use MCPs to give AI agents the ability to query third-party applications in a conversational way. The way AI-based applications query data is much different than a standard relational database. AI-based answers require vector databases and a confidence score that is then used to provide a response to users. Unified APIs hide this complexity, making AI integrations easier for developers.

For example, suppose that you want to build an agent that pulls data from Salesforce to identify Q1 sales revenue and compare it to Q3 sales revenue. Your agent uses a unified API MCP first. The unified API makes a call to the Salesforce API, generates an answer, and sends it back to the agent.

All vendors have their own way of handling MCP and AI agents. Merge handles MCP with their product called Merge Agent Handler. Your business deploys an MCP server with Merge integrations enabled. Apideck exposes many more integrations from a single MCP server, but the wide range of options consumes more tokens than a business might have a budget for.

As we mentioned, Unified.to doesn’t store data locally, so its MCP server handles agent queries with real-time results. This is Unified.to’s unique value proposition for its standard and AI-based endpoints.

To make it easier for businesses, Paragon uses ActionKit for integrations. Anthropic lists ActionKit on the MCP registry and can support multi-tenant MCP clients. Think of ActionKit as the agent-facing layer that abstracts the more complex nature of AI-based data queries, like an SDK that abstracts standard API calls for a specific software.

Instead of coding, users build their own integrations using a no-code workflow builder in a friendly interface. For enterprise B2B agencies, the builder eliminates the overhead of development. Developers don’t need to handle granular data access permissions, OAuth tokens for each user, and multi-tenant tool connections.

Which Top Unified API Is Right For Your Business?

Every unified API has its own benefits and challenges. The best way to make a decision is to gather your business requirements and look at our comparison table. You should ask yourself what business problem needs to be solved and make a choice from there. Don’t just settle for what problems you have today, but ask yourself what problems you might have in the future. By preparing for your future growth, you can ensure that your unified API can scale with your business growth.

API integrations have shifted from being a “nice to have” to being a core part of enterprise applications. To save on development time and make integrations more user-friendly, Paragon’s graphical workflow design interface gives the power of coding to your users. Instead of writing code, users can drag and drop integrations within your applications. With Paragon, your applications become an added value to your customers, especially if they don’t have a development team to build more complex integrations. Paragon makes it simple for them, and you have a completely white-labeled solution embedded in your customer-facing applications.

See it for yourself and book a demo with us. Find out why fast-growing B2B SaaS companies have chosen Paragon as their unified API integration partner.

FAQs

Can a unified API communicate with my SaaS tools?

Yes, a unified API lets you consume a single API that can then query multiple third-party platforms like Office 365, Google Workspace, Salesforce, Hubspot, Slack, Microsoft Teams, and any other cloud-provider. Ensure that your unified API vendor of choice has a connector for each SaaS platform.

Do unified APIs support AI agents?

Yes, most unified APIs work with Model Context Protocol (MCP), which is a standard for communication between the unified API vendor’s MCP server and your AI agents. Ensure that your vendor of choice offers MCP servers, ideally multi-tenant MCP servers to avoid limitations.

How does a unified API connect my third-party SaaS account to their internal system?

You still use OAuth to connect with your SaaS tools, but the unified API vendor manages tokens and refresh tokens.

How does a unified API connect to third-party SaaS providers?

A unified API has their own process for connecting to SaaS providers, but not every vendor supports the same SaaS applications. Ensure that your vendor of choice supports the SaaS applications that your business integrates into its own applications.

Which unified API has the easiest integration?

Paragon has a graphical user interface where users don’t need coding experience to build automation workflows. Users can drag and drop automation logic into an interface and build their workflows. The visual workflow creator is a unique offer that other B2B unified APIs do not offer.