Editorial update (August 2026): This article was originally published on August 17, 2018. It is preserved as a historical snapshot, with corrections for retired or renamed APIs.
Application programming interfaces (APIs) let developers use capabilities and data exposed by other software instead of rebuilding every component from scratch.
APIs are the foundation of many things we know as it pertains to digital technology. This includes the cloud, mobile, and the Internet of Things (IoT). An API is basically a user interface for software. Software applications use an API in the same way humans use interfaces for apps. This standard makes it easy for software and the actual interface to communicate.
When this article was first published in 2018, the APIs below illustrated how reusable software interfaces could support new products and partnerships. Several names and access models have changed since then.
The list is preserved as a historical snapshot. Current replacements or product-status notes are included where the original description would otherwise be misleading.
Google Contacts API (retired; use People API)
Google turned down the legacy Contacts API on January 19, 2022. Developers should use the Google People API to read and manage an authenticated user's contacts, subject to the required OAuth scopes and the People API data model.
Slack API
Slack provides APIs for building apps and automations around conversations, messages, files, and workspace events. Developers should consult Slack's current platform documentation because available methods, scopes, and app requirements evolve over time.
A RESTful API is one that uses HTTP requests to retrieve, post, and delete data. It is based on "representational state transfer (REST) technology," which is used in many web services.
Typical integrations can post or retrieve permitted content, react to workspace events, and connect Slack workflows with external business systems.
Twitter Stream API (historical; now X API v2)
The streaming interface described in the original article is no longer the current product. The X API v2 Filtered Stream provides near-real-time posts that match developer-defined rules. Access requires a developer project and app, and the available limits depend on the current access tier.
Houndify
Houndify remains a SoundHound developer platform for adding voice and text interactions to applications through its APIs, SDKs, and cloud service.
IBM Watson APIs (historical product family)
IBM Watson represented a broad family of AI services when this list was published. IBM has since changed its AI portfolio and product naming, so developers should verify the current IBM offering and API documentation before choosing an implementation path.
Lusha API
Lusha offers API access to business contact and company data. Any implementation should be reviewed against Lusha's current product terms, permitted-use rules, and applicable privacy and data-protection requirements.
NASA API
NASA maintains an Open APIs portal that makes selected agency data and imagery available to developers. The catalog and rate limits vary by service, so production applications should use the documentation for the specific NASA API.
Amazon Product Advertising API
Amazon's Product Advertising API gives eligible Amazon Associates program participants programmatic access to supported product information. Eligibility, data fields, usage policies, and rate limits should be checked in Amazon's current documentation.
Shopping Cart API
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Conclusion
Application programming interfaces let developers reuse existing capabilities, but an API is dependable only when its owner maintains clear documentation, versioning, access terms, security controls, and a deprecation path.
The broader lesson still holds: a well-documented API can help developers build on an existing platform. Before selecting one, verify its present status, access model, data terms, and deprecation policy.
This article was written by Michael Isberto. Michael Isberto is the Blog Director and a Content Writer for Colocation America. He received his B.A. in Communication Studies with an emphasis in Public Relations at CSUSB. Isberto is a Communication professional with additional experience in Public Relations, Marketing, and Social Media.
