A unified API gives a SaaS company one integration that reaches dozens or hundreds of third-party apps in a category, such as every major CRM, HRIS or accounting system, through a single schema and a single auth flow. The best unified API platforms in 2026 are Merge, Unified.to, Apideck, Nango, Paragon, Truto, Prismatic, Cyclr, Kombo and Rutter, and each one makes a different trade-off between breadth, depth and control.
The category matters more this year because customers expect native integrations on day one, and AI features raise the bar further. An AI assistant inside your product is only as useful as the customer data and actions it can reach. Most vendors on this list now expose their connectors as tools for agents, often through a hosted MCP server, alongside the classic REST endpoints.
We cover both pure unified APIs (normalized data models per category) and embedded integration platforms (embedded iPaaS and code-first integration infrastructure), because SaaS teams evaluate them side by side. If your main goal is giving an AI agent tools rather than syncing customer data, also see our guide to the top Composio alternatives.
Unified API Platforms At A Glance
Platform
Best For
Approach
Pricing Model
Merge
B2B SaaS needing HR, ATS, CRM, accounting and ticketing data
Normalized models with stored syncs
Per linked account; Launch tier from $650/mo
Unified.to
Teams wanting many categories without stored customer data
Normalized models, real-time pass-through
API calls; from $750/mo, unlimited connections
Apideck
Accounting, HRIS and file storage integrations with predictable cost
Normalized models plus proxy
Per active consumer; from $599/mo
Nango
Engineering teams that want code-level control
Code-first functions on managed auth
Free tier, then usage-based from $50/mo
Paragon
Embedded workflows and agent actions in one product
Embedded iPaaS plus ActionKit API
Per connected user, quote-based
Truto
Wide category coverage with customizable mappings
Declarative config, no data stored
Per connector per year, from $999
Prismatic
Integration marketplaces with low-code and code options
Embedded iPaaS with TypeScript SDK
Per instance, quote-based
Cyclr
Visual, low-code embedded integrations
Embedded iPaaS with marketplace
Flat tiers plus per active connector
Kombo
HR tech and recruiting software
Normalized HRIS, ATS, LMS models
Platform fee plus per connected customer
Rutter
Fintechs needing commerce, accounting and payments data
Normalized financial data models
Custom quote, free starter for testing
Best Unified API Platforms In 2026
1. Merge — Normalized Unified API Across Six B2B Data Categories
Merge is one of the most widely used unified API providers. Its Merge Unified product covers accounting, ATS, CRM, file storage, HRIS and payroll, and ticketing, with a common data model in each category so one integration reaches hundreds of underlying apps. Merge syncs and stores normalized data, which makes it easy to query large volumes and keeps you insulated from third-party rate limits.
The company has broadened into AI over the past year. Agent Handler connects agents to pre-built tools and MCP connectors with credential management, DLP-style scanning of tool inputs and outputs, and full audit logs. That lets one vendor serve both your customer-data syncs and your agent tool layer.
Pricing is per production linked account. The Launch plan includes the first three linked accounts free, then costs $650 per month for up to 10 and $65 for each additional account, with daily syncs. Professional and Enterprise plans add custom fields, field-level scopes, faster syncs and SLAs on contract pricing.
Common models across six categories
Custom fields and field-level scopes on higher tiers
Agent Handler for MCP tools with audit logging
2. Unified.to — Real-Time Pass-Through Across 36+ Categories
Unified.to takes a different path from Merge. It normalizes data into one model per category, but calls the source API at request time instead of storing a synced copy of customer records. For security reviews and data residency questions, that zero-storage design is often the deciding factor. If you do want a local copy, an optional sync can write records into your own database.
Breadth is its standout. The pricing page lists 36+ unified APIs and roughly 1,446 integrations across categories such as CRM, HR and payroll, ATS, accounting, commerce and calendar. A passthrough option reaches vendor-specific endpoints outside the common model. Unified.to also runs a hosted MCP server with US, EU and AU regions and per-connection tool filtering.
Pricing is based on API calls rather than connections, and every plan includes unlimited customer connections. Grow starts at $750 per month for 750,000 calls, Pro at $1,500 and Scale at $3,000, with a 30-day free trial on Grow and Pro. That model favors products with many customers and moderate call volume.
3. Apideck — Per-Consumer Pricing With Proxy Access Built In
Apideck offers a unified API across about a dozen categories, including accounting, CRM, HRIS, ATS, file storage and ERP. Each category comes with a normalized model, and a proxy API lets you call any underlying endpoint the model does not cover. Vault, its hosted auth component, handles customer connections and credential storage.
Its pricing is easy to forecast. Apideck charges per active consumer, meaning a customer whose connection made at least one call or webhook event that month, rather than per API call. Launch starts at $599 per month for 25 consumers with one category. Scale starts at $1,299 per month for 100 consumers with three categories plus custom field mapping and data scopes. Enterprise unlocks unlimited categories, SSO and a white-label Vault.
Apideck also hosts an MCP server that exposes the categories in your plan to AI agents, with Vault managing the auth. It suits SaaS products whose integration roadmap is anchored in finance and back-office systems.
4. Nango — Code-First Integrations On Open Managed Auth
Nango is built for engineering teams that want to own integration logic rather than accept a fixed schema. It handles auth for more than 1,000 APIs and MCP servers, then lets you write your own syncs, actions and tools as code on top, starting from roughly 7,000 pre-built templates. The source is on GitHub under the Elastic License, and self-hosting is available on Enterprise.
That makes Nango a common pick among paragon alternatives for developers who found embedded iPaaS too opinionated. You get managed OAuth, token refresh, retries and observability, but the data model is whatever your product needs. The same functions can be exposed to agents through Nango’s MCP and tools product.
Pricing is usage-based. The free plan includes 10 connections and capped compute. Pay-as-you-go costs $50 per month in credits, billed at $0.29 per connection, $0.72 per compute hour and $0.50 per GB transferred, and Enterprise adds commitment discounts, self-hosting and SLAs.
Auth for 1,000+ APIs
Custom syncs, actions and tools written in code
Source available, self-hostable on Enterprise
5. Paragon — Embedded Workflows Plus ActionKit For AI Agents
Paragon is an embedded integration platform that bundles several products. Workflows handles event-driven integration logic with retries and rate-limit handling. Managed Sync pulls customer files and permissions into retrieval pipelines. ActionKit gives agents one API and MCP server for over 1,000 integration actions across CRMs, ticketing, email and chat. The Connect Portal provides the customer-facing auth flow.
The site lists more than 130 pre-built connectors, plus the option to build custom ones for any third-party API. Paragon is a strong fit if you want one vendor for user-facing integration setup, background syncs and agent tool calling, without building auth handling yourself.
Pricing is not published. Usage scales with connected users (tenants using integrations), on Pro and Enterprise plans that both offer unlimited integrations. Enterprise adds self-hosting, dynamic field mapping and SAML SSO. ActionKit is included in every plan.
6. Truto — Declarative Unified API With Per-Connector Pricing
Truto treats connectors as configuration rather than code. Every mapping between a third-party API and the unified model is declarative and can be customized with JSONata, so you can adjust a field mapping for one customer without waiting on the vendor. Like Unified.to, Truto calls the underlying API in real time and does not store customer data between requests.
Coverage is wide. The site claims more than 850 integrations across 50+ SaaS categories, ranging from accounting, CRM and HRIS to security and payment gateways. Any integration can be turned into a scoped MCP server with one API call, restricted by method, tag and time-to-live.
Pricing is per connector per year with unlimited connections and API calls. Expansion starts at $999 per connector per year with a 10-connector minimum. Enterprise starts at $1,999 per connector with single-tenant deployment and SSO. A 30-day sandbox is available with no credit card.
7. Prismatic — Embedded iPaaS With Low-Code And TypeScript Paths
Prismatic is an embedded integration platform for B2B software companies that ship many customer-specific integrations. Teams can build in a low-code designer or write integrations in TypeScript with the code-native SDK, version them in Git and deploy through CI/CD. Customers activate and configure integrations through an embedded marketplace inside your app.
Multi-tenant operations are its core strength: per-customer auth, configuration and monitoring are handled without per-customer engineering. Higher tiers add an embedded workflow builder for end users, on-prem connectivity and private or GovCloud hosting. An MCP flow server exposes your integrations and workflows as tools that agents can call on behalf of each customer.
Prismatic prices per instance (a deployed integration for a customer) and states it never bills on API calls or executions. All plans are quote-based, and Scale already includes unlimited integrations, customers and team members.
8. Cyclr — Visual Embedded Integrations With Published Pricing
Cyclr is a UK-based embedded iPaaS with more than 600 pre-built connectors and a visual, low-code workflow builder. SaaS vendors use it to build integration templates once and let customers deploy them from an embedded marketplace, with each customer account kept separate. A Connector Creation Toolkit covers niche or proprietary systems, and private deployment is available.
Cyclr has also added an MCP PaaS that turns APIs and integration logic into governed MCP servers, sold as its own product from $999 per month on shared hosting.
Unlike most vendors here, Cyclr publishes starting prices. The native embedded product starts at 100 per active connector per month and 100,000 API calls), $2,595 on Growth and $7,195 on Scale. You pay for connectors used in the last 30 days rather than per customer, which helps when many customers share the same few connectors.
9. Kombo — HR, Recruiting And Learning Data For HR Tech
Kombo focuses on one vertical and goes deep. It offers unified APIs for HRIS and payroll, ATS, assessment and background checks, and LMS, with hundreds of off-the-shelf integrations. It has offices in Berlin and New York, which makes it a natural shortlist pick for HR tech companies selling on both sides of the Atlantic.
Read and write access is included from the entry tier, so recruiting tools can push candidates and applications back into an ATS, not only read jobs. Enterprise plans add sandboxes for systems such as SAP and Workday, SFTP, SAML SSO and custom integrations with SLAs. Kombo has also launched AI Apply, a browser agent product for applying to jobs in systems without open APIs.
Pricing combines a fixed annual platform fee with a per-customer connection fee that decreases with volume. Kombo does not bill on API calls, and you stop paying for a connection once the customer deactivates it.
10. Rutter — Financial Data Unified API For Fintechs And Banks
Rutter is a unified API for commerce, accounting and ERP, payments and ads data, plus a separate bank feeds API. It is designed for B2B fintechs and financial institutions: lenders underwriting small businesses, bill pay and expense tools, FP&A products and sales tax software. Accounting coverage includes QuickBooks Online and Desktop, Xero, NetSuite and Sage Intacct.
The depth here is in financial objects such as invoices, bills, payouts and transactions, the data lenders and finance tools actually need. Rutter has also launched Embedded ERP and agentic commerce products, reflecting how AI agents are starting to transact on behalf of businesses.
Pricing is custom and depends on connection volume, capabilities used and target platforms. A free starter plan includes 30 days of building with sandbox data on QuickBooks, Xero, FreshBooks and Zoho Books, with no credit card required.
How To Choose A Unified API Platform
Do You Need Breadth Or Depth?
Count the categories on your 18-month roadmap. If you need CRM, HRIS, accounting and ticketing, a broad provider like Merge, Unified.to or Truto saves you from stitching vendors together. If your product lives in one domain (HR tech, lending, recruiting), a vertical specialist such as Kombo or Rutter usually covers more systems in that domain and models them in more detail.
Will A Normalized Model Cover Your Customers’ Custom Fields?
Normalized models are fast to ship, but enterprise customers rely on custom objects and fields. Check whether custom field mapping is included on the tier you can afford (Merge and Apideck reserve it for higher plans), whether mappings can be changed per customer (Truto), or whether a code-first platform like Nango is a better fit because you define the model yourself.
Do You Need Stored Syncs Or Real-Time Calls?
Stored syncs make bulk queries and analytics simple but put customer data on another vendor’s servers and introduce sync delay. Real-time pass-through, used by Unified.to and Truto, keeps no copy and returns current data, but each request depends on the source API’s speed and rate limits. Many teams choose based on what their security reviewers will approve.
How Is Authentication Handled For Your Customers?
Look at the hosted auth component your customers will see: whether it can be white-labeled, whether you can use your own OAuth apps, and whether you can bring your own secrets manager. Token refresh and reconnect prompts should be automatic, since broken connections are the most common source of integration support tickets.
Which Pricing Unit Fits Your Growth?
Per-connection pricing (Merge, Kombo, Apideck’s active consumers) scales with customer count. API-call pricing (Unified.to) scales with usage. Per-connector pricing (Truto, Cyclr) scales with how many apps you support. Model your expected customers, connectors and call volume over two years before you sign, because the cheapest option at 20 customers is rarely the cheapest at 2,000.
Frequently Asked Questions
What Is A Unified API?
A unified API is a single API that sits in front of many third-party apps in the same category and translates them into one common data model. Your engineers build against it once, and the provider maintains the individual connectors.
What Is The Difference Between A Unified API And An Embedded Integration Platform?
A unified API normalizes data so every CRM looks the same to your code. An embedded integration platform (embedded iPaaS) gives you tools to build integration workflows, often with a visual builder and a marketplace your customers use, without forcing a common schema.
What Are Good Paragon Alternatives?
Prismatic and Cyclr are the closest embedded iPaaS alternatives to Paragon. Nango suits teams that want code-level control, while Merge and Unified.to fit teams that prefer normalized data models over workflow building.
Can Unified APIs Be Used By AI Agents?
Yes. Merge, Unified.to, Apideck, Nango, Paragon, Truto, Prismatic and Cyclr all offer ways to expose integrations as agent tools, most often through MCP. For more on that layer, see our roundup of the top MCP gateways.
Conclusion
There is no single best unified API, only the best fit for your categories, data policy and pricing curve. Broad providers like Merge, Unified.to and Truto cover the most ground, vertical specialists like Kombo and Rutter go deepest in their domains, and Nango, Paragon, Prismatic and Cyclr give you more control over the integration logic itself.
If you want to feature your company on this list, email us or submit a form in the Top Choices section. After a thorough assessment, we’ll decide whether it’s a valuable addition.
