In 2025, the "build vs. buy" debate for SaaS integrations is effectively settled. With the average enterprise now managing over 350+ SaaS applications, engineering teams no longer have the bandwidth to build and maintain dozens of 1:1 connectors.
When evaluating your SaaS integration strategy, the decision to move to a unified model is driven by the State of SaaS Integration trends we see this year: a shift toward real-time data, AI-native infrastructure, and stricter "zero-storage" security requirements.
In this guide, we break down the best unified API platforms in 2025, categorized by their architectural strengths and ideal use cases.
What is a Unified API? (And Why You Need One Now)
A Unified API is an abstraction layer that aggregates multiple APIs from a single category into one standardized interface. Instead of writing custom code for Salesforce, HubSpot, and Pipedrive, your developers write code for one "Unified CRM API."
While we previously covered the 14 Best SaaS Integration Platforms, 2025 has seen a massive surge specifically toward Unified APIs for CRM, HRIS, and Accounting because they offer a higher ROI by reducing maintenance by up to 80%.
Top Unified API Platforms for 2025
1. Knit (Best for Security-First & AI Agents)
Knit has emerged as the go-to for teams that refuse to compromise on security and speed. While "First Gen" unified APIs often store a copy of your customer’s data, Knit’s zero-storage architecture ensures data only flows through - it is never stored at rest.
- Key Strength: 100% events-driven webhook architecture. You get data in real-time without building resource-heavy API polling and throttling logic.
- Highlight: Knit is the primary choice for developers building Integrations for AI Agents, offering a specialized SDK for function calling across apps like Workday or ADP.
- Ideal for: Security-conscious enterprises and AI-native startups.
2. Merge
Merge remains a heavyweight, known for its massive library of integrations across HRIS, CRM, ATS, and more. If your goal is to "check the box" on 50+ integrations as fast as possible, Merge is a good choice
- Key Strength: Excellent observability and a dashboard that allows non-technical support teams to troubleshoot API authentication issues.
- The Trade-off: Merge relies on a storage-first, polling-based architecture. For teams requiring a more secure alternative to Merge, Knit’s pass-through model is often preferred.
- Ideal for: Companies needing to go "wide" across many categories quickly.
3. Nango
Nango caters to the "code-first" crowd. Unlike pre built unified APIs, Nango gives developers tools to build those and offers control through a code-based environment.
- Key Strength: Custom Unified APIs. If a standard model doesn’t fit, Nango lets you modify the schema in code.
- Ideal for: Engineering teams that need the flexibility of custom-built code
4. Kombo
If your target market is the EU, Kombo offers great coverage. They offer deep, localized support for fragmented European platforms
- Key Strength: Best in class coverage for local European providers.
- Ideal for: B2B SaaS companies purely focus on Europe as the core market
5. Apideck
Apideck is unique because it helps you "show" your integrations as much as "build" them. It’s designed for companies that want a public-facing plug play marketplace.
- Key Strength: "Marketplace-as-a-Service." You can launch a white-labeled integration marketplace on your site in minutes.
- Ideal for: Product and Marketing teams using integrations marketplace as a lead-generation engine.
Comparative Analysis: 2025 Unified API Rankings
Deep-Dive Technical Resources
If you are evaluating a specific provider within these unified categories, explore our deep-dive directories:
- HRIS: Workday Guide | BambooHR Directory | HiBob Directory
- CRM: Salesforce API Guide | HubSpot Directory
- ATS: Greenhouse Integration | Lever API Directory
- Accounting: QuickBooks Online Tutorial | NetSuite Guide
The Verdict: Choosing Your Infrastructure
In 2025, your choice of Unified API is a strategic infrastructure decision.
- Choose Knit if you are building for the Enterprise or AI space where API security and real-time speed are non-negotiable.
- Choose Merge if you have a massive list of low-complexity integrations and need to ship them all yesterday.
- Choose Nango if your developers want to treat integrations as part of their core codebase and maintain it themselves
Ready to simplify your integration roadmap?
Sign up for Knit for free or Book a demo to see how we’re powering the next generation of real-time, secure SaaS integrations.
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