Business APIs

Business data and services

15 APIs in this category · last checked 2 October 2026
15
APIs listed
1
need no API key (7%)
2
CORS enabled (13%)
15
HTTPS (100%)

This directory lists 15 business APIs. Use the filters below to narrow by authentication, HTTPS support and CORS. Every entry shows whether it needs authentication, serves over HTTPS and allows cross-origin requests, so you can pick one that fits your stack before you read a single doc page.

Showing 15 of 15 APIs

Apache Superset

Manage dashboards, charts, datasets and database connections in Apache Superset through a REST API with Swagger docs. The software itself is free, open source and self hosted.

Auth: apiKey HTTPS CORS: Unknown

Freelancer

Post projects, place bids and manage freelance jobs on the Freelancer.com marketplace. Access needs a registered OAuth2 application and an approved API key from Freelancer.

Auth: OAuth HTTPS CORS: Unknown

Mailchimp

Send marketing campaigns, manage audiences and pull engagement data from Mailchimp. The Marketing API uses a simple API key and works on Mailchimp's free plan for small contact lists.

Auth: apiKey HTTPS CORS: Unknown

Mailjet

Send transactional and marketing emails built with MJML or plain HTML templates. Authentication is a public and private API key pair, with a free tier of 6000 emails per month.

Auth: apiKey HTTPS CORS: Unknown

Instatus

Create and update incidents, maintenance windows and components on a hosted status page. Requests use a bearer API key taken from the account's developer settings page.

Auth: apiKey HTTPS CORS: Unknown

Charity Search

Look up US nonprofits by EIN, name, category or location across a database of over 2.5 million charities. Now at charityapi.com, keys are issued through a 3scale developer portal.

Auth: apiKey HTTPS CORS: Unknown

Domainsdb.info

Search registered domain names and basic registration records such as creation and expiration dates. No signup or key is needed, making it an easy free lookup for domain research.

Auth: No HTTPS CORS: No

Markerapi

Search the USPTO trademark database by serial number, wordmark, owner or expiration date, paginated at 100 results per page. The free plan allows 1000 searches a month.

Auth: apiKey HTTPS CORS: Unknown

Tomba Email Finder

Find, verify and enrich business email addresses by domain or name across 14 endpoints. New accounts get 75 free credits and 25 free monthly searches with no card required.

Auth: apiKey HTTPS CORS: Yes

Trello

Manage boards, lists, cards and custom fields to organize projects and tasks. Trello's REST API now lives under Atlassian's developer site and uses an API key plus an OAuth token.

Auth: OAuth HTTPS CORS: Unknown

Smartsheet

Read and write sheets, rows, attachments, reports and automation rules in Smartsheet. Access needs an API token or OAuth2 app and is limited to Business and Enterprise plans.

Auth: apiKey HTTPS CORS: Unknown

Google Analytics

Pull reporting and near real time analytics data for websites and apps you own, including the GA4 Data API. Access requires an OAuth2 consent flow through a Google Cloud project.

Auth: OAuth HTTPS CORS: Unknown

Gmail

Read, send, label and organize Gmail messages and threads through a RESTful API. It needs OAuth2 consent and a verified Google Cloud project, and is free within Google's usage quotas.

Auth: OAuth HTTPS CORS: Unknown

Redash

Pull query results, cached data and dashboard contents from a Redash instance. Redash is open source and self hosted, and API keys can be scoped to a user or to a single query.

Auth: apiKey HTTPS CORS: Yes

Square

Take payments, issue refunds, manage orders and run a hosted checkout page for in person or online sales. A free developer sandbox lets you test before switching to a live account.

Auth: OAuth HTTPS CORS: Unknown

Best Business APIs for Developers

A business API allows developers to access company profiles, corporate registry data, VAT validation, and business entity information programmatically. These APIs power KYB verification, CRM enrichment, and B2B data pipelines.

Trello and Smartsheet cover project and work management, though Smartsheet access is locked to paid Business and Enterprise plans, so check your plan before building anything. Mailchimp and Mailjet handle email marketing with workable free sending tiers, while Square is the pick for payments, with a free sandbox for testing before going live. Gmail and Google Analytics need an OAuth2 consent flow and a Google Cloud project, more setup than a plain key. Tomba suits lean outreach tools, with free monthly searches and no card required. The pitfall in this category is churn: several listed APIs have since been folded into bigger platforms or shut down, so confirm the docs still resolve before you build on them.

What to check before you pick one

  • Data freshness: Corporate registry data changes frequently; prefer APIs that synchronize with official sources regularly.
  • Global coverage: For international B2B apps, choose APIs that cover multiple jurisdictions and countries.
  • VAT validation: EU VAT number validation is critical for e-commerce businesses serving European customers.

Frequently Asked Questions

What are business APIs?

Business APIs provide programmatic access to company information, corporate registries, VAT numbers, business entity lookups, and commercial data for due diligence and B2B applications.

Can I look up a company by registration number through an API?

Yes. APIs like Companies House (UK) and OpenCorporates allow you to query companies by registration number and retrieve details like directors, filing history, and registered address.

What can I build with a business data API?

You can build KYB (Know Your Business) verification tools, CRM enrichment pipelines, competitor research dashboards, and supplier due diligence platforms using the APIs in this directory.

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