Top 100 API Integrations

TL;DR: A REST API is a standardized interface that lets software systems communicate over HTTP using stateless, predictable requests. This guide covers 100 REST API integrations organized by business function, including CRM, sales, billing, marketing, geolocation, and data pipelines. APIs were selected based on adoption, documentation quality, authentication support, and relevance to business data workflows. For teams building automated pipelines, Integrate.io connects 150+ of these APIs without custom code.

Key Takeaways

• REST APIs are the dominant integration standard for modern business applications, covering everything from CRM and billing to analytics and geolocation.
• The best APIs for business share four traits: clear documentation, reliable uptime, standard authentication (OAuth, API key), and predictable rate limits.
• Data pipeline teams get the most value from APIs that connect high-volume transactional systems (Salesforce, Shopify, Stripe) directly to a data warehouse.
• Maintaining custom API integrations is expensive. Rate limit changes, auth updates, and schema drift all require ongoing engineering time.
• Integrate.io's API management platform and ETL platform connect to 150+ APIs through pre-built connectors, so your team builds pipelines in hours, not weeks.

Integration is a critical part of modern business operations, but connecting different systems can be difficult without a technical background. This article lists 100 REST API integrations organized by business function, with use case context and integration complexity ratings to help you choose the right ones for your stack.

What Is a REST API?

A REST API (Representational State Transfer Application Programming Interface) is a standardized interface that allows software systems to communicate over HTTP using stateless, predictable requests. REST APIs are the dominant integration standard for modern business applications. When your CRM automatically syncs a new contact to your email platform, that's a REST API call in action. Unlike proprietary integrations, REST APIs follow consistent conventions that make them faster to connect and easier to maintain at scale.

REST is not the only API architecture. SOAP APIs use XML and are common in legacy enterprise systems. GraphQL lets clients request exactly the data they need, which reduces over-fetching. But REST remains the default choice for most SaaS platforms because it's lightweight, well-documented, and broadly supported.

What makes a REST API "good" for business use? Four things matter most:

• Documentation quality: clear endpoint references, code samples, and error codes
• Rate limits: how many requests per minute or hour the API allows before throttling
• Authentication support: OAuth 2.0, API key, or SAML for secure, governed access
• Uptime SLA: a published reliability commitment you can hold the provider to

For a deeper look at how APIs feed into automated workflows, see the complete guide to API ingestion and the Integrate.io glossary entry on application integration.

How We Selected These 100 API Integrations

Not every API belongs on a business integration list. The 100 APIs below were selected based on the following criteria:

• Adoption and ecosystem maturity: widely used by business teams, not just developers
• Documentation quality: official docs are complete, current, and include authentication guidance
• Authentication support: OAuth 2.0, API key, or SAML available
• Rate limits and reliability: track record of consistent uptime and predictable throttling behavior
• Relevance to data pipeline use cases: APIs that move meaningful business data (transactions, contacts, events, financials)
• Active maintenance: the product is live, independently available, and not deprecated or acquired into a closed platform

Entries that failed these criteria (deprecated products, acquired platforms no longer available as standalone APIs) were removed from the original list and replaced with current alternatives.

Top 100 REST API Integrations

Here are the top 100 REST API integrations as of August 2026, organized by business function. Each entry includes a primary use case, authentication type, and integration complexity rating (Low / Medium / High).

CRM

CRM APIs let your sales and support tools share customer data automatically, eliminating manual data entry and reducing errors across your stack.

Sales

Sales APIs connect your revenue tools to the rest of your stack, so deal data, lead scores, and pipeline stages stay in sync without manual exports.

Billing

Billing and payment APIs connect your revenue systems to your data warehouse, enabling real-time financial reporting without manual exports.

Outreach and Lead Generation

Marketing

Geolocation Services

Analytics and Business Intelligence

Project Management and Collaboration

E-Commerce and Operations

Communications and Notifications

Data and Infrastructure

Top API Integrations for Data Pipelines

The most valuable API integrations for data teams are those that connect high-volume transactional systems, like Salesforce, Shopify, and Stripe, directly to your data warehouse. The ten APIs below are the most commonly used by data engineers and analytics managers building production pipelines.

Salesforce REST API

Salesforce exposes contacts, opportunities, accounts, and custom objects through a well-documented REST API. For data teams, it's the primary source of CRM truth. Integrate.io connects Salesforce bidirectionally, so you can both pull CRM data into your warehouse and push enriched data back to sales reps.

Auth: OAuth 2.0 | Complexity: Medium

Snowflake API

The Snowflake SQL API lets you submit SQL statements and retrieve results programmatically, without a JDBC or ODBC driver. It's the standard interface for orchestrating warehouse queries from external tools. Integrate.io's data pipeline platform uses Snowflake as a primary destination for ETL and ELT workflows.

Auth: OAuth 2.0 / Key Pair | Complexity: Medium

Google BigQuery API

BigQuery's REST API enables programmatic table creation, data ingestion, and query execution at scale. It's the destination of choice for teams running analytics on Google Cloud. Integrate.io supports BigQuery as both a source and destination across ETL and CDC pipelines.

Auth: OAuth 2.0 | Complexity: Medium

Shopify API

Shopify's REST and GraphQL APIs expose orders, products, customers, inventory, and fulfillment data. For e-commerce data teams, it's typically the highest-volume transactional source. Integrate.io syncs Shopify data to your warehouse on a schedule as frequent as 60 seconds.

Auth: OAuth 2.0 | Complexity: Low

Stripe API

Stripe's API covers charges, subscriptions, invoices, refunds, and payout data. It's the financial source of record for most SaaS and e-commerce businesses. Connecting Stripe to your warehouse via Integrate.io gives finance and analytics teams real-time revenue visibility without manual exports.

Auth: API Key | Complexity: Low

HubSpot API

HubSpot's API covers contacts, companies, deals, marketing emails, and form submissions. For teams running inbound marketing, it's the primary engagement data source. Integrate.io connects HubSpot to downstream analytics tools and data warehouses through pre-built connectors.

Auth: OAuth 2.0 | Complexity: Low

AWS S3 API

Amazon S3's REST API is the backbone of most data lake architectures. It handles object storage, retrieval, and lifecycle management at any scale. Integrate.io uses S3 as both a staging layer and a direct destination for file-based pipeline workflows.

Auth: AWS Signature v4 | Complexity: Low

Twilio API

Twilio's API covers SMS, voice, email (via SendGrid), and messaging data. For data teams, it's a source of communication event data that feeds customer journey analytics. Integrate.io connects Twilio data to your warehouse for cross-channel reporting.

Auth: API Key | Complexity: Low

Zendesk API

Zendesk's API exposes tickets, agents, users, satisfaction ratings, and SLA metrics. Support data combined with CRM and product data gives a complete picture of customer health. Integrate.io syncs Zendesk to Snowflake, BigQuery, and Redshift for unified customer analytics.

Auth: OAuth 2.0 / API Key | Complexity: Low

Slack API

Slack's API enables reading and writing messages, accessing channel history, and triggering notifications from external systems. For data teams, it's the standard destination for pipeline alerts and monitoring notifications. Integrate.io supports Slack as an alert channel for pipeline health events.

Auth: OAuth 2.0 | Complexity: Low

How to Connect APIs Without Writing Custom Code

Building and maintaining custom API integrations is expensive. Every time a provider changes a rate limit, rotates an auth token format, or updates a schema, someone on your engineering team has to fix it. For organizations running dozens of integrations, that maintenance burden compounds fast.

A low-code integration platform handles that complexity for you.

Integrate.io connects to 150+ APIs and data sources through pre-built connectors, letting data teams build and automate pipelines without writing custom integration code. The platform is SOC 2 certified and HIPAA, GDPR, and CCPA compliant, so API data flows through a secure, audited layer rather than custom scripts that are difficult to govern.

Key capabilities for API-driven workflows:

• API management: generate secure REST APIs from any database source in under five minutes, with full Swagger/OpenAPI documentation auto-generated
• ETL and ELT pipelines: pull data from any API source, transform it with 220+ built-in transformations, and load it to your warehouse
• Change Data Capture: replicate database changes to your warehouse with sub-60-second latency, no polling required
• MCP Server: use your AI assistant (Claude, Cursor, or any MCP-compatible client) to inspect, build, edit, and execute pipelines using natural language

For teams already using AI assistants in their development workflow, the MCP Server extends Integrate.io into those environments directly. You can describe the pipeline you need in plain language and have it built, validated, and running without leaving your AI workspace.

Ready to connect your APIs without the maintenance overhead? Talk to an Expert or schedule a call to ask about the 14-day pilot program.

Frequently Asked Questions

What is the difference between an API and an API integration?

An API is the interface a software system exposes so other programs can communicate with it. An API integration is the connection you build between two systems using that interface. The API is the door; the integration is the pipeline you build through it to move data automatically between applications.

What are the most commonly used REST APIs for business?

The most widely used REST APIs in business data workflows are Salesforce (CRM), Stripe (payments), Shopify (e-commerce), HubSpot (marketing), Zendesk (support), Google Analytics (web data), and Slack (communications). These APIs appear in the majority of modern data stack architectures because they cover the highest-value transactional data sources.

How do I connect multiple APIs to a single data pipeline?

Use a low-code integration platform that supports multiple source connectors. Integrate.io lets you pull data from multiple API sources into a single pipeline, apply transformations, and load the unified output to your data warehouse. This eliminates the need to write and maintain separate custom scripts for each API.

What is API rate limiting and how does it affect integrations?

Rate limiting is a restriction set by the API provider on how many requests you can make within a given time window (for example, 1,000 requests per hour). If your integration exceeds the limit, requests are throttled or rejected. Well-designed integration platforms handle rate limit management automatically, queuing requests and retrying on failure rather than dropping data.

Do I need to code to use REST API integrations?

Not with a low-code platform. Integrate.io's visual interface lets technical and non-technical users build API-connected pipelines using pre-built connectors and a drag-and-drop interface, no custom code required. For teams that prefer code-first workflows, the platform also exposes a fully documented REST API and supports Cron-based scheduling and SQL execution.

How does Integrate.io handle API authentication and security?

Integrate.io supports all major authentication methods including OAuth 2.0, API key, SAML, LDAP, and Active Directory. The platform is SOC 2 certified and HIPAA, GDPR, and CCPA compliant. All data is encrypted in transit and at rest. Integrate.io acts as a pass-through layer and does not store your data, so credentials and records stay within your governed environment.

How do I know if an API is still actively maintained?

Check the provider's changelog or developer blog for recent updates, look for a published uptime SLA or status page, and verify the authentication method is current (OAuth 2.0 is the modern standard; APIs still using only HTTP Basic Auth may be unmaintained). Avoid building pipelines on APIs whose parent products have been acquired or sunset.

Integrate.io: Delivering Speed to Data

Reduce time from source to ready data with automated pipelines, fixed-fee pricing, and white-glove support. Integrate.io connects to 150+ APIs and data sources through pre-built connectors, with SOC 2, HIPAA, GDPR, and CCPA compliance built in.

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