What is a Unified API?

What is a Unified API?

A unified API normalizes data across multiple third-party APIs into a single schema. If you integrate Salesforce and Close, you'll notice Salesforce calls them 'Contacts' while Close calls them 'Persons'. A unified API abstracts this away. You interact with one standard entity, and the API handles the underlying translation.

Modern unified APIs also provide managed OAuth flows and standardized pagination across all supported providers.

Common Data Model

Without a unified API, you map hundreds of distinct entities across every integration. With a unified CRM API, you query a single Contacts endpoint. You don't need to read the Close documentation to find out they call it a Person. You write against the common data model once, and it works across every supported provider.

The Case for Unified APIs

This comment from a frustrated Redditor highlights why building third-party integrations is a massive time sink:

I always dislike doing integration with 3rd party APIs. Other than Stripe, the documentation is almost always terrible. It's not tailored to my language, there's too many links to other things I don't need to know in the beginning, and asks me to make choices on things I don't know anything about yet.

Then, I have to pick from a variety of client libraries, some of questionable quality, because the service couldn't be bothered to maintain an official lib (I'm not using esoteric langs), and then authentication is always a pain.

That's all before I get to the good stuff of just getting to play the data. And that's when I actually care about getting to use the API.

Other times, I just want it over and done with, because it's not the core of the product, and I feel like integration is just this long slog and chore.

Does anyone else feel this way? How do you deal with getting through integration quickly or painlessly?

Posted on Reddit by u/iamwil

• Organizations use an average of 130 SaaS solutions (source). These systems need to communicate.

• Application growth continues with organizations using an average of 1,061 different applications. Just 29% of these applications are integrated. (source)

• Integration hinders digital transformation for 80% of organizations. (source)

How Useful is a Common Data Model Really?

• Without it, engineers write custom data mapping logic for every new integration. This is tedious, error-prone, and scales poorly.

• With a common data model, adding a new integration requires zero new mapping code. You authenticate the user, and the existing unified integration works immediately.

What is Unified API Also Known as?

• Meta API

• Universal API

• Unified schema

• Common data model

How do Unified API Solutions Work?

Unified APIs act as an abstraction layer between your application and dozens of third-party APIs. Under the hood, a modern unified API architecture cleanly separates three concerns: the unified interface (what developers call), the proxy layer (how third-party calls are made), and the mapping layer (how data is transformed).

When you make a request to a unified endpoint, the system:

1. Maps your unified query parameters into the specific format the target integration expects.
2. Calls the lower-level proxy layer, which handles the raw HTTP request, authentication (OAuth tokens, API keys), pagination, and rate limiting.
3. Evaluates a set of JSONata expressions to transform the raw third-party response back into the canonical unified schema.

graph TD
    A[Your App] -->|Unified Request| B(Unified API Router)
    B -->|Map Request| C{Mapping Engine}
    C -->|Proxy Call| D[Proxy Layer]
    D -->|Raw HTTP| E((Third-Party API))
    E -->|Raw Response| D
    D -->|Raw JSON/XML| C
    C -->|JSONata Transform| B
    B -->|Unified Response| A

Because the mapping layer uses a powerful expression language like JSONata, it can handle complex transformations - conditionals, array transforms, and date formatting - ensuring the output shape is identical whether the underlying data came from Salesforce or HubSpot.

What are Some Popular Categories of Unified APIs?

Here are some popular unified APIs:

Unified CRM API

A unified CRM API normalizes data from platforms like Salesforce, HubSpot, Pipedrive, and Close. It abstracts away provider-specific endpoints so your application can manage pipelines, track interactions, and update sales records using a single schema.

The data model typically revolves around a core trinity: Accounts (companies), Contacts (people), and Opportunities (active deals). You also get standardized endpoints for Engagements, Notes, and Tasks to build a historical timeline of a deal.

This normalization is highly effective for AI agents. For example, an agent can capture an inbound lead, enrich the company data, create the Account and Lead, and generate a Task for the right sales rep based on territory rules. Another common pattern is automated meeting logging, where an integration parses meeting transcripts and logs the summarized Notes against the correct Contact and Opportunity.

flowchart LR
  subgraph contacts[Contacts]
    direction LR
    c1[Salesforce: Contacts] & c2[HubSpot: Contacts] & c3[Pipedrive: Persons] & c4[Close: Contact] --> trutoC[Truto: Contacts]
  end

  subgraph users[Users]
    direction LR
    u1[Salesforce: Users] & u2[HubSpot: Owners] & u3[Pipedrive: Users] & u4[Close: User] --> trutoU[Truto: Users]
  end

  subgraph accounts[Accounts]
    direction LR
    a1[Salesforce: Account] & a2[HubSpot: Organisation] & a3[Pipedrive: Organisation] & a4[Close: Lead] --> trutoA[Truto: Accounts]
  end

Unified CRM API with Salesforce, HubSpot, Pipedrive and Close.

Unified Accounting API

A unified accounting API enforces standard double-entry accounting logic across diverse financial platforms like QuickBooks, Xero, Wave, and Zoho. It handles the full financial lifecycle, from core ledger configuration (Accounts, JournalEntries) to Accounts Receivable (Invoices, Payments) and Accounts Payable (Expenses, PurchaseOrders).

Engineers use this to build automated order-to-cash workflows. When an order is placed on an external e-commerce platform, the system automatically creates a Contact, generates an Invoice with the correct line Items, and logs the Payment upon checkout to keep the ledger synced. It also simplifies intelligent expense parsing, where an automated processor extracts receipt data, queries the API to find the matching Account (like "Meals & Entertainment"), creates an Expense, and uploads the receipt image.

flowchart LR
  subgraph invoices[Invoices]
    direction LR
    i1[QuickBooks: Invoice] & i2[Xero: Invoice] & i3[Wave: Invoice] & i4[Zoho: Invoice] --> trutoI[Truto: Invoices]
  end

  subgraph contacts[Contacts]
    direction LR
    c1[QuickBooks: Customer] & c2[Xero: Contact] & c3[Wave: Customer] & c4[Zoho: Contact] --> trutoC[Truto: Contacts]
  end

  subgraph accounts[Accounts]
    direction LR
    a1[QuickBooks: Account] & a2[Xero: Account] & a3[Wave: Business] & a4[Zoho: Organization] --> trutoA[Truto: Accounts]
  end

Unified Accounting API with QuickBooks, Xero, Wave, and Zoho Books.

Unified HRIS API

A unified HRIS API provides a consistent schema to read and write HR and payroll data across systems like Gusto, Rippling, SAP SuccessFactors, and Keka. The Employee entity is the nexus of this graph, linking to Employments (start dates, contract types), JobRoles, Locations, and Groups. It also standardizes complex domains like compensation, benefits, and time-off balances.

The most common engineering use case is automated identity provisioning. By polling the Employees and Employments endpoints, IT systems can automatically provision or de-provision software licenses and access levels when someone joins or leaves the company. It also enables reliable directory synchronization to build unified internal org charts by mapping Employees to their respective Groups and JobRoles.

flowchart LR
  subgraph employees[Employees]
    direction LR
    e1[Gusto: Employee] & e2[Rippling: Person] & e3[SAP SF: User] & e4[Keka: Employee] --> trutoE[Truto: Employees]
  end

  subgraph departments[Departments]
    direction LR
    d1[Gusto: Department] & d2[Rippling: Department] & d3[SAP SF: Cost Center] & d4[Keka: Department] --> trutoD[Truto: Departments]
  end

  subgraph payruns[Pay runs]
    direction LR
    p1[Gusto: Pay run] & p2[Rippling: Pay run] & p3[SAP SF: Payroll] & p4[Keka: Pay run] --> trutoP[Truto: Pay runs]
  end

Unified HRIS API with Gusto, Rippling, SAP Success Factors, and Keka.

Unified ATS API

A unified ATS API allows programmatic systems to manage job postings, candidate pipelines, and hiring outcomes across platforms like Lever, Greenhouse, Workable, and Recruitee. The architecture is pipeline-driven: Jobs define a sequence of JobInterviewStages, and a Candidate submits an Application that traverses these stages.

You can use this to build custom, real-time career pages by fetching Jobs, Departments, and dynamic JobFormFields. For AI-driven sourcing, an agent can parse inbound LinkedIn profiles, automatically create a new Candidate, attach their parsed resume, and generate an Application for the most relevant open role. You can also automate pipeline triage by monitoring submitted Scorecards and automatically moving an Application to the next stage if the feedback is universally positive.

flowchart LR
  subgraph candidates[Candidates]
    direction LR
    c1[Lever: Candidate] & c2[Greenhouse: Candidate] & c3[Workable: Candidate] & c4[Recruitee: Candidate] --> trutoC[Truto: Candidates]
  end

  subgraph jobs[Jobs]
    direction LR
    j1[Lever: Opportunity] & j2[Greenhouse: Job] & j3[Workable: Job] & j4[Recruitee: Job] --> trutoJ[Truto: Jobs]
  end

  subgraph applications[Applications]
    direction LR
    a1[Lever: Application] & a2[Greenhouse: Application] & a3[Workable: Application] & a4[Recruitee: Application] --> trutoA[Truto: Applications]
  end

Unified Ticketing API

A unified ticketing API normalizes information from issue tracking and support systems like Asana, ClickUp, Linear, Jira, and Zendesk. The model centers on Tickets, governed by strict TicketStatus, TicketTypes, and TicketPriorities. Tickets exist within Workspaces and are assigned to internal Users or Teams, while external Contacts and Accounts represent the requesters.

This API is heavily used for cross-platform syncing. When an external customer opens a Zendesk Ticket, an orchestration loop can automatically generate an identical Ticket in Jira for the engineering Workspace, keeping Comments and statuses in sync between the two tools. It also powers automated triage, where an AI agent analyzes inbound emails, assigns the correct tags, and routes the Ticket to the appropriate Team.

flowchart LR
  subgraph tickets[Tickets]
    direction LR
    t1[Zendesk: Ticket] & t2[Jira: Issue] & t3[Linear: Issue] & t4[Front: Conversation] --> trutoT[Truto: Tickets]
  end

  subgraph comments[Comments]
    direction LR
    c1[Zendesk: Comment] & c2[Jira: Comment] & c3[Linear: Comment] & c4[Front: Message] --> trutoC[Truto: Comments]
  end

Unified Ticketing API with Zendesk, Jira, Linear, and Front.

Unified File Storage API

A unified file storage API provides a standardized data model to interact with cloud storage providers like Google Drive, Dropbox, OneDrive, and Box. It abstracts away provider-specific folder structures and permissions, allowing programmatic systems to traverse directories and manipulate files using a single schema.

The core universal entity is the DriveItem, which represents any object within a storage volume - whether it's a file, a folder, or a shortcut. Because a DriveItem can contain other DriveItems as children, you can easily navigate the directory tree. The API also standardizes access control, mapping Permissions to specific Users or Groups for each item.

This normalization is highly effective for AI agents and automated workflows. For example, an agent building a semantic search index can recursively crawl a drive by listing DriveItems, checking if an item is a folder to traverse deeper, or downloading the document binary to feed into a vector database. It also simplifies automated provisioning, where a workflow creates a new project folder structure and applies strict permissions granting access only to the relevant team groups.

flowchart LR
  subgraph driveitems[DriveItems]
    direction LR
    f1[Google Drive: File] & f2[Dropbox: File] & f3[OneDrive: DriveItem] & f4[Box: File] --> trutoF[Truto: DriveItems]
  end

  subgraph permissions[Permissions]
    direction LR
    p1[Google Drive: Permission] & p2[Dropbox: Member] & p3[OneDrive: Permission] & p4[Box: Collaboration] --> trutoP[Truto: Permissions]
  end

Unified User Directory API

A unified user directory API provides a standardized schema to manage identity, access, and organizational structure across identity providers like Google Workspace, Microsoft Entra ID, and Okta. It abstracts provider-specific implementations, allowing developers to manage users, roles, licenses, and groups through a single interface.

The model operates on an identity-centric relational graph. Organizations and Workspaces act as the fundamental containers. The User is the core node, belonging to Groups and receiving specific permissions via RoleAssignments. The API also tracks resource consumption by monitoring how Licenses are distributed among users.

Engineers use this to build automated onboarding and offboarding flows. You can programmatically create users, assign them to departmental groups, and provision software licenses on day one - or instantly revoke access when an employee leaves. It also powers centralized access management, ensuring least-privilege access across connected tools by synchronizing application permissions with the directory's defined roles.

flowchart LR
  subgraph users[Users]
    direction LR
    u1[Google Workspace: User] & u2[Entra ID: User] & u3[Okta: User] --> trutoU[Truto: Users]
  end

  subgraph groups[Groups]
    direction LR
    g1[Google Workspace: Group] & g2[Entra ID: Group] & g3[Okta: Group] --> trutoG[Truto: Groups]
  end

  subgraph activities[Activities]
    direction LR
    a1[Google Workspace: Event] & a2[Entra ID: AuditLog] & a3[Okta: LogEvent] --> trutoA[Truto: Activities]
  end

Other SaaS Categories with Unified APIs

• Analytics

• Application Development

• Business Intelligence

• Cloud Storage

• E-commerce

• Email

• Event Management

• Helpdesk

• IM (Instant Messaging)

• Incident Management

• Knowledge Management

• Marketing

• Payment Gateway

• Receipt

• Remote Support

• Sales Enablement

• Sales Intelligence & Data

• Scheduling

• Single Sign-On (SSO)

• Subscription Platforms

• Survey

• Video

• Voice

• WhatsApp connectors

What are the Advantages of Unified APIs?

Engineering Advantages

• Faster time to market: Ship integrations in days, not months. You write code against one API instead of dozens.

• Reduced maintenance: Let the provider handle API version changes, deprecations, and undocumented edge cases.

• Standardized authentication: Stop building custom OAuth flows for every provider. The unified API handles token refreshes automatically.

• One pagination format: Iterate through records using a single cursor-based format across all supported platforms.

• Automated data pipelines (Sync Jobs): Instead of writing custom cron jobs to poll APIs, advanced unified API platforms offer built-in sync engines. You define a sync job with dependencies, and the platform handles execution, pagination, and incremental syncing.

• Unified Webhooks: Dealing with different provider webhook formats is a massive headache. A unified API normalizes inbound provider events into canonical record:created, record:updated, or record:deleted events, verifies the signatures, and delivers them to your endpoints via a reliable queue.

• Preserved raw data: A good unified API doesn't hide the underlying data. Every mapped response includes a remote_data object containing the original third-party payload, ensuring you always have an escape hatch for custom fields.

Product Advantages

• Faster feature velocity: Spend engineering cycles on your core product, not building plumbing.

• Keep users in your app: Native integrations prevent users from bouncing to third-party automation tools like Zapier.

Business Advantages

• Unblock sales: Say "yes" when enterprise prospects ask if you integrate with their obscure legacy CRM.

• Expand total addressable market (TAM): Support entire software categories out of the box.

• Reduce churn: Deeply integrated products are harder to rip out.

What are the Disadvantages of Unified APIs?

• Platform risk: You are taking a hard dependency on a third-party vendor. Ensure you have an escape hatch. Lalit, CTO at Clearfeed.ai, shares more about designing a fail-safe architecture.

• Abstraction leaks: Sometimes you need a highly specific endpoint that the unified model doesn't cover. (This is where proxy layers save you).

• Latency: Routing requests through an intermediary adds network hops. Ensure the provider's latency overhead is acceptable for your use case.

• Debugging complexity: When an integration fails, you have to determine if the issue is in your code, the unified API layer, or the underlying provider.

We Can Build the Integrations on Our Own?

You can, but you probably shouldn't. Building integrations isn't just writing the initial code - it's maintaining OAuth flows, handling rate limits, and fixing breaking changes.

Here's Subhash Choudhary, CTO at Dukaan, discussing the pros and cons of building software in-house: Build vs. Buy: The True Cost of Building SaaS Integrations In-House

We also wrote about whether you should use a unified API provider here: Should I use a unified API provider

Can't we Use Zapier Instead?

Zapier is great for internal workflows, but it's a poor experience for native product integrations. It forces your users to leave your app, create a Zapier account, and build their own mappings. Read more: Zapier: Read This if You Are Asking Your Customers to Integrate Using Zapier

Common Misconceptions Regarding Unified APIs

Unified API Providers Force-Fit Their Unified Models on Developers

Modern platforms treat the unified schema as a baseline, not a cage. If the default mapping doesn't fit your needs, you can override the JSONata mapping expressions at the environment or individual account level.

Every normalized response in Truto includes a remote_data field containing the raw, untouched payload from the third-party API. If a customer uses a highly specific custom field in Salesforce, you can access it immediately via remote_data without changing any mappings.

For entirely custom operations, you can bypass the mapping layer entirely and use the Proxy API. The Proxy API handles the authentication and rate limiting, letting you make raw HTTP requests directly to the third-party endpoints.

Unified API Providers Don't Allow Custom OAuth

With Truto, you can use your own client ID and secret. You are not forced to use our OAuth apps, meaning your users see your brand during the authentication flow, not ours.

Unified APIs are an Inferior Alternative to Workflow Automation Tools

They serve different purposes. Workflow automation tools are for non-technical users building one-off internal processes. Unified APIs are for engineers building native, scalable product integrations in code.

Unified APIs Demand Broad Scopes of Data Access

Legacy unified APIs often asked for maximum permissions. Truto allows you to customize the exact OAuth scopes you request, adhering to the principle of least privilege.

End-Users May Not be Comfortable Seeing Another App While They Connect Their Accounts

If you use your own OAuth credentials, the end-user never sees Truto. They only see your application requesting access to their data.

We also take data security seriously. Any data stored is encrypted at rest, and Truto is SOC 2 Type 2, ISO:270001, GDPR, and HIPAA compliant.