A unified API gives you one interface for many providers in the same category. Instead of integrating separately with several CRMs, you integrate once with a unified CRM API and get contacts, companies and deals in a common format, whichever CRM a customer uses.
That's genuinely useful for some products and a poor fit for others. This guide explains how unified APIs work, where they help, where they don't, and what building one yourself involves.
A unified API sits between your application and the providers. It has three main parts:
A common data model for the category. For a CRM, that might define a contact with name, email, phone, company and owner.
Adapters for each provider that translate between the provider's API and the common model, in both directions.
Authorization and connection management, so each customer can connect their account and the unified API can call the provider for them.
Your application calls the unified endpoint, such as "list contacts", and the adapter for that customer's provider makes the actual API calls and maps the results.
Adapters translate each provider into a common model. Fields outside the model need separate handling.
Many similar providers. If your customers use a dozen different HR systems and you need employee names and departments from all of them, a common model saves a lot of repetitive work.
Read-heavy use cases. Pulling standard records is where normalized models work best.
Speed to coverage. You can support many providers in a category quickly.
Consistent code. Your application handles one data shape.
A common model only includes what most providers share. Provider-specific features, custom objects and custom fields often don't fit. Many unified APIs offer passthrough requests or custom field mapping for these cases, but then you're working with provider-specific data again.
Creating or updating records means satisfying each provider's validation rules, required fields and workflows. A normalized "create deal" request can fail differently in every CRM.
Providers model the same concept differently. One CRM's "deal" has stages tied to pipelines; another uses a different structure entirely. Mapping can hide meaningful differences.
Some unified APIs sync data into their own store and serve it from there; others call providers in real time. Each has implications for freshness, rate limits and data residency.
Some teams build an internal unified layer for their own product. It can make sense when you need several providers in a category but only a specific slice of data your product actually uses.
Building it involves:
Designing the model around your product's needs, not around every provider's full schema.
Writing adapters that map provider responses into your model and handle pagination, rate limits and errors.
Handling authorization for each provider.
Keeping raw data alongside normalized data, so you can add fields later without re-fetching.
Testing adapters continuously against real provider sandboxes.
Pathfix OAuth is not a unified API. It handles authorization, token storage, refresh and authenticated API passthrough across 350+ providers, and your application calls each provider's own API. That suits teams who want full access to provider features, or who are building their own focused unified layer and need the authorization part handled.
