Accounting API

Unified Accounting API

Connect your SaaS, fintech, or marketplace product to QuickBooks, Xero, NetSuite and other accounting systems through one normalized API layer. Start with production-tested connector architecture for authentication, data normalization, platform routing, sync, error handling, and accounting data exchange instead of building every integration foundation independently.

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What Is the Unified Accounting API Accelerator?

Satva’s Unified Accounting API Accelerator is a pre-built integration foundation for SaaS products, fintech applications, marketplaces, and software platforms that need to connect with multiple accounting and ERP systems.

Instead of building separate integration architecture for QuickBooks, Xero, NetSuite, FreshBooks, Zoho Books and other platforms, your product communicates through a common REST API and normalized accounting data model.

The accelerator handles common integration infrastructure such as platform authentication, field normalization, connector routing, API errors, retries, rate limits, webhooks, and scheduled synchronization.

Your engineering team can then adapt the foundation to your product-specific workflows, mappings, business rules, and customer experience.

Built for

SaaS • Fintech • Marketplaces • Product Teams

Core capabilities

REST API • OAuth • Normalization • Webhooks • Background Sync • Error Handling

Accounting data

Accounts • Invoices • Payments • Transactions • Contacts • Tax Rates • Financial Reports

Step 1

1. Why SaaS Teams Need a Unified Accounting API

Your SaaS customers rarely use the same accounting system.

One customer may use QuickBooks Online, another Xero, while a larger account may depend on NetSuite or another ERP.

Supporting each platform directly means dealing with different authentication flows, field structures, API endpoints, rate limits, error responses, and synchronization requirements.

The accounting concepts may be similar, but the APIs are not.

An invoice, customer, account, payment, or journal entry can be represented differently across every platform. As additional accounting integrations are added, engineering teams end up maintaining multiple versions of the same integration logic.

A unified accounting API introduces a common layer between your product and those accounting systems.

Your application works with normalized accounting models and consistent endpoints, while platform-specific connectors handle authentication, field mapping, requests, responses, and exceptions behind the API layer.

Here’s a straightforward comparison of what integration life looks like with and without a unified layer:

✕ Without a Unified Accounting API

  • ✕ Separate connector logic for each accounting platform

  • ✕ Platform-specific field names and data structures

  • ✕ Different OAuth and authentication workflows

  • ✕ Individual rate-limit and retry handling

  • ✕ Separate error-handling logic

  • ✕ Growing maintenance requirements as platforms are added

✓ With the Unified Accounting API Accelerator

  • ✓ Common REST endpoints across supported accounting systems

  • ✓ Normalized accounting objects and field structures

  • ✓ Centralized connector routing

  • ✓ Consistent error responses

  • ✓ Shared authentication and sync architecture

  • ✓ A reusable foundation for adding accounting platforms

Step 2

2. Accounting & ERP Platforms Supported by the Unified API

he accelerator provides a common integration architecture across accounting and ERP platforms while each connector handles the requirements of its underlying system.

Core connector coverage currently includes QuickBooks, Xero, NetSuite, FreshBooks, Zoho Books, and Clear Books.

Need MS Dynamics Business Central, Sage Intacct, or SAP? Those are available too, just on one of our extended plans.

PlatformConnector IDBest FitMarket
XeroxeroSMB / Cloud accountingAU, UK, NZ, US
QuickBooksquickbooksSMB to EnterpriseUS, Global
FreshbooksfreshbooksFreelancers and small businessUS, Global
Zoho BookszohoSMB to mid-marketGlobal
Clear BooksclearbooksUK-focused SMBUK
NetSuitenetsuiteEnterprise ERPGlobal Enterprise

Need another accounting or ERP connector?

Additional integration requirements can include platforms such as Microsoft Dynamics 365 Business Central, Sage Intacct, SAP, and other accounting systems based on the implementation scope. Discuss your required platform mix during the accelerator demo.

Step 3

3. Unified Accounting API Architecture: Normalization, Routing & Sync

The Unified Accounting API sits between your SaaS application and each connected accounting platform.

Your application sends a standard REST request using a common accounting model.

The API validates and normalizes the request, identifies the customer’s connected accounting system, routes the request through the relevant platform connector, and transforms the resulting response back into the unified schema.

Here’s what happens when you make a request:

  1. Your Application - Frontend or backend makes a standard REST call to the Unified API

↓ Request received at Unified API layer

  1. Field Normalizer Validates and maps your request fields to platform-specific format

  2. Platform Router Identifies the connected platform and dispatches to the right connector

  3. Platform Connector Authenticates with the platform, makes the API call, handles errors

↓ Response normalized back to unified schema

  1. Your Application Receives one consistent JSON response - always the same structure

The part that makes this powerful is that each accounting platform has its own dedicated connection.

All the complicated, platform-specific stuff lives there completely out of sight. When we add support for a new platform, nothing on your end needs to change.

Synchronous and Background Accounting Sync

Different accounting workflows require different processing patterns.

  • Synchronous requests can support operations where the application needs an immediate response, such as retrieving an account, invoice, customer, or other individual record.

  • Background processing can be used for larger synchronization jobs involving substantial transaction volumes or multiple accounting objects. These jobs can be processed asynchronously and monitored through callbacks, webhooks, or job-status workflows depending on the implementation.

Step 4

4. Built for Production-Scale Accounting Integrations

Accounting integrations become more complex as the number of connected customers, transactions, and supported platforms grows.

The accelerator is designed to provide reusable infrastructure for common production requirements rather than leaving each SaaS team to solve them independently.

Background Jobs

Large imports and synchronization tasks can be processed outside the request-response cycle so high-volume jobs do not depend on a single long-running API request.

Rate-Limit Management

Platform connectors can account for API-specific limits and apply connector-level handling rather than forcing your product to implement separate rate-limit logic for every accounting system.

Retry and Error Handling

Normalized error structures make it possible to build common application behavior around authentication failures, invalid data, unavailable platforms, rate limits, and missing records.

Incremental Data Sync

Supported endpoints can use modification timestamps and pagination to retrieve data incrementally rather than repeatedly requesting an entire accounting dataset.

Webhooks and Scheduled Sync

Depending on the underlying platform and workflow, accounting data can be synchronized through event-driven webhooks, scheduled jobs, or a combination of both.

Multi-Customer SaaS Architecture

SaaS platforms and marketplaces can use the integration layer as the common accounting foundation while maintaining customer-specific accounting connections and workflows.

Step 5

5. Normalized Chart of Accounts API Model

Chart of accounts is a useful example of why accounting data normalization matters.

QuickBooks, Xero, FreshBooks, Zoho Books, Clear Books, and NetSuite can represent similar accounting concepts using different field names, structures, and supported attributes.

The Unified Accounting API maps platform-specific account data into a common model so your application can work with predictable fields regardless of the connected accounting system.

The mapping reference below shows how the common account model relates to fields exposed by individual platforms.

Field Mapping Reference

The table below shows exactly how each platform names these fields behind the scenes.

You’ll always see our unified field names in your responses this is just so you understand what’s happening under the hood.

A couple of things to keep in mind before you dive in:

  • Fields marked * are required they will always be there in every response, no exceptions.

  • Fields showing simply mean that particular platform doesn’t support that field. It’s not an error, it’s just not something they track.

Unified FieldXeroQuickBooksFreshbooksZoho BooksClear BooksNetSuite
accountId *AccountIDIduuidaccount_idid-
accountCode *CodeAcctNumnumberaccount_code--
accountName *NameNamenameaccount_nameaccount_name-
classificationClassClassification----
descriptionDescriptionDescriptiondescriptiondescription--
currencyCurrencyCodeCurrencyRef.value-currency_code--
bankAccountNumberBankAccountNumber-----
accountTypeTypeAccountTypetypeaccount_typegroup_name-
accountSubType-AccountSubTypesub_type---
isBankAccountBankAccountType: BANK-----
isActiveStatus (Active only)Activestateis_activehidden-
modifiedDateUpdatedDateUTCMetaData.LastUpdatedTimeupdated_atlast_modified_time--
isSubAccount-SubAccountsub_accountsis_child_present--
currentBalance-currentBalance-current_balance--
parentRef → id-ParentRef.value-parent_account_id--

Note on Xero’s isActive field: Xero’s Status field has three possible values: Active, Archive, and Deleted.

The unified isActive field maps to true only when Status equals ‘Active’. Archive and Deleted accounts are returned as isActive: false.

What Each Platform Actually Supports

Not every accounting platform tracks the same information and that’s okay.

The table below gives you a clear picture of which fields are available on each platform, so you can make smart decisions about what to show your users and what to filter on.

If a field is ticked for a platform, you can count on it being there.

If it’s not, it’s worth having a fallback in mind or simply not surfacing that field for users on that platform.

Unified FieldXeroQuickBooksFreshbooksZohoClear BooksNetSuite
accountId-
accountCode--
accountName-
classification----
description--
currency---
bankAccountNumber-----
accountType-
accountSubType----
isBankAccount-----
isActive-
modifiedDate--
isSubAccount---
currentBalance----
parentRef → id----

Step 6

6. API Response: The Account Object

A normalized API response allows your application to consume one predictable structure even when the source accounting platform changes.

The following example shows a unified account response.

GET /api/v1/accounts/{accountId} → 200 OK
{
 "accountId": "acc_7f3a2b14-9c8d-4e1f",
 "accountCode": "1200",
 "accountName": "Trade Debtors / Accounts Receivable",
 "accountType": "CURRENT_ASSET",
 "accountSubType": "AccountsReceivable",
 "classification": "ASSET",
 "description": "Money owed to the business by customers",
 "currency": "USD",
 "isActive": true,
 "isBankAccount": false,
 "isSubAccount": false,
 "currentBalance": 48230.00,
 "parentRef": null,
 "modifiedDate": "2025-04-12T08:33:17Z",
 "_meta": {
 "platform": "xero",
 "rawId": "bd9f2c1a-4518-4c3e-8b72-f190e4a6c3d1",
 "syncedAt": "2025-04-12T08:40:02Z"
 }
}

Fields such as accountId, accountName, accountType, currency, and modifiedDate use the unified model rather than exposing a different response structure for every accounting platform.

The _meta object preserves useful source information, including the connected platform, the platform’s original record identifier, and synchronization metadata.

This gives your product a normalized application model while still retaining enough source context for troubleshooting, record linking, and platform-specific workflows.

Step 7

7. Accounting API Endpoints for Accounts, Invoices, Payments & Reports

The accelerator exposes common REST endpoints for frequently used accounting objects and financial data.

Depending on the connected accounting platform and implementation scope, SaaS products can use the unified layer to retrieve or exchange chart-of-accounts data, invoices, payments, transactions, contacts, tax information, reports, and journal entries.

MethodEndpointDescription
GET/accountsList all accounts in the chart of accounts. Supports pagination and modified_after filtering.
GET/accounts/{id}Fetch a single account record by its unified ID.
GET/balance-sheetRetrieve the balance sheet report. Accepts date, currency, and company query parameters.
GET/profit-lossRetrieve the profit & loss statement for a given date range.
GET/transactionsList all transactions. Use modified_after for incremental syncs.
POST/journal-entriesCreate a journal entry. Body accepts the unified JournalEntry model.
GET/tax-ratesList all tax rates available in the connected accounting platform.
GET/contactsList customers and suppliers using the unified Contact model.
GET/invoicesList all invoices. Supports filtering by status, date range, and contact.
GET/paymentsList payment records, including linked invoice references.
Query Parameters

These query parameters work across all list endpoints:

ParameterType / DefaultDescription
modified_afterISO 8601 timestampReturn only records modified after this time. Use for incremental syncs.
pageinteger (default: 1)Page number for paginated results.
page_sizeinteger (default: 100)Number of records per page. Maximum is 500.
expandmodel name stringReturn full nested objects instead of just IDs. E.g. expand=contacts.

Accounting Data Supported by the API

Chart of Accounts

Retrieve normalized account records and account classifications.

Invoices

Retrieve invoices using common filters and response models.

Payments

Access payment records and their related invoice references.

Transactions

Retrieve transaction data and perform incremental synchronization.

Customers & Suppliers

Work with contacts through a common contact model.

Journal Entries

Create journal entries using a normalized request model where supported.

Tax Rates

Retrieve available tax codes and rates from the connected platform.

Financial Reports

Access financial data such as balance sheets and profit-and-loss reports.

Step 8

8. Accounting API Error Handling, Rate Limits & Retries

Every accounting platform exposes errors differently. A unified error model gives your application one consistent structure for handling common integration failures.

Connector-specific failures can be translated into normalized API responses covering validation errors, expired authentication, permission issues, missing records, platform rate limits, and service availability.

HTTP CodeStatusError CodeMeaning
400Bad RequestINVALID_FIELDA required field is missing or has an invalid value.
401UnauthorizedINVALID_TOKENThe API key or account token is missing or expired.
403ForbiddenINSUFFICIENT_SCOPEThe linked account does not have permission for this data.
404Not FoundRECORD_NOT_FOUNDThe requested record does not exist in the platform.
429Too Many RequestsRATE_LIMITEDRate limit exceeded. Check the Retry-After header.
503UnavailablePLATFORM_DOWNThe connected accounting platform is temporarily unavailable.

How Rate-Limit Handling Works

Individual accounting platforms impose their own API limits. The connector layer can isolate those platform-specific rules from your product so common retry, queueing, and error-handling workflows can be managed centrally.

A 429 RATE_LIMITED response should expose the relevant retry behavior to the application while the connector continues to handle platform-specific implementation details.

Step 9

9. Who Is the Unified Accounting API Accelerator Built For?

Vertical SaaS Platforms

Add accounting connectivity to vertical software without building separate foundational integration architecture for every accounting system your customers use.

B2B SaaS Products

Sync operational data such as invoices, customers, payments, transactions, and financial records into customer accounting systems.

Fintech Applications

Connect financial workflows with the customer’s accounting system of record while working through consistent data models and endpoints.

Marketplaces

Support sellers or merchants using different accounting systems through a common integration architecture designed for multiple customer connections.

Billing and Subscription Platforms

Send billing, invoice, payment, and customer data into accounting systems while keeping application logic consistent across connectors.

Procurement and Expense Platforms

Exchange suppliers, accounts, purchase-related transactions, bills, payments, and related accounting information with supported ERP and accounting systems.

Step 10

10. Build Direct Accounting Connectors or Start with an Accelerator?

Building Direct IntegrationsUnified Accounting API Accelerator
Separate API implementation per platformCommon API layer
Separate authentication logicReusable authentication architecture
Platform-specific data modelsNormalized accounting models
Separate error structuresCommon error model
Individual retry/rate-limit logicCentral connector architecture
Repeated connector foundationsStart with pre-built integration components
Engineering owns every connector layerEngineering focuses more on product-specific workflows

Direct integrations can still make sense when your product supports only one accounting platform or requires highly platform-specific capabilities.

A unified accounting API becomes more valuable when your roadmap requires multiple accounting systems and much of the integration logic can be standardized across them.

The accelerator does not eliminate implementation work. It provides a tested foundation that can be adapted to your product’s accounting workflow, customer requirements, mapping rules, and production environment.

Frequently Asked Questions

What is a unified accounting API?
A unified accounting API gives a software product one common integration layer for connecting with multiple accounting and ERP systems. Instead of exposing completely different application logic for QuickBooks, Xero, NetSuite, and other platforms, the API normalizes common accounting objects, routes requests to the appropriate connector, and returns consistent response structures.
How does a unified accounting API help SaaS companies?
It reduces the amount of repeated connector infrastructure SaaS engineering teams need to build and maintain. Common functions such as authentication, accounting data normalization, routing, errors, retries, synchronization, and rate-limit handling can be managed through one integration architecture.
Can one API connect QuickBooks, Xero, and NetSuite?
Yes. A unified accounting API can provide a common application layer across QuickBooks, Xero, NetSuite, and other supported accounting systems while each platform-specific connector handles the requirements of its underlying API.
Is the Unified Accounting API a zero-code integration?
No. The accelerator reduces the connector foundation that needs to be built from scratch, but product integration, accounting mapping, business rules, validation, configuration, and production testing are still required.
Can the API handle large accounting data sync jobs?
The accelerator architecture supports background processing, pagination, incremental synchronization, retry handling, rate-limit management, webhooks, and scheduled synchronization patterns for workflows that do not fit a simple real-time request.
Who should use a unified accounting API accelerator?
It is most relevant to SaaS platforms, fintech products, marketplaces, billing software, procurement applications, and other products whose customers use different accounting or ERP platforms and therefore require multiple accounting integrations.

Ideal for

SaaS platforms adding accounting connectivity to close enterprise deals.
Fintech apps syncing invoices, payments, and customers to a client's books of record.
Product teams that lost a quarter to "Do you integrate with QuickBooks?"

Under the hood

Unified REST API with normalized objects across platforms.
OAuth 2.0 connection flows for QuickBooks Online, Xero, and NetSuite.
Webhooks and scheduled sync for invoices, bills, payments, customers, and chart-of-accounts data.
Production-tested error handling, rate-limit management, and retry logic.

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