Free Business & Productivity APIs — ranked by value

CRM, docs, enrichment, scheduling

Scores rate free-tier value on a 1–10 scale. How scores work →

Notion API Business & Productivity Token Read and write Notion pages, databases, and blocks to build integrations on top of a team's workspace. 3 req/sec
Airtable API Business & Productivity Token Programmatically read and write records in Airtable bases as a flexible spreadsheet-database hybrid. 5 req/sec
Google Sheets API Business & Productivity OAuth Create, read, and update Google Sheets spreadsheets and cell data programmatically. 300/min
Google Calendar API Business & Productivity OAuth Manage events, calendars, and free/busy availability across Google Calendar accounts. 1M req/day
HubSpot API Business & Productivity Token Manage CRM contacts, companies, deals, and marketing automation through HubSpot's REST API. 100 req
Pipedrive API Business & Productivity API key Sales-focused CRM API for managing deals, pipelines, contacts, and activities. Free trial
Calendly API Business & Productivity OAuth Access scheduled events, invitees, and availability to automate meeting booking workflows. 1k req/min
Cal.com API Business & Productivity API key Open-source scheduling platform API for managing bookings, event types, and availability. Self-hosted
Trello API Business & Productivity API key Manage Kanban boards, lists, and cards to automate project workflows in Trello. 300 req
Todoist API Business & Productivity Token Create and manage tasks, projects, and labels in Todoist for to-do automation. 450 req
Asana API Business & Productivity Token Manage tasks, projects, and workflows for team project management via REST. 150 req/min
Linear API Business & Productivity API key GraphQL API for issue tracking, projects, and engineering workflow automation. 1.5k req/hr
ClickUp API Business & Productivity Token Manage tasks, lists, docs, and time tracking across ClickUp workspaces. 100 req/min
monday.com API Business & Productivity Token GraphQL API for boards, items, and columns in the monday.com Work OS platform. 1M/min
Hunter.io API Business & Productivity API key Find and verify professional email addresses associated with a domain or person. 25 msg/mo
Abstract Company Enrichment API Business & Productivity API key Enrich any domain or email into structured company data like industry, size, and location. 1 req/sec
People Data Labs API Business & Productivity API key Person and company enrichment, search, and identity-resolution data via REST. Free tier
Apollo.io API Business & Productivity API key Sales intelligence API for contact and company search, enrichment, and engagement. Per-endpoint caps
Typeform API Business & Productivity Token Create forms and retrieve form responses for surveys and lead-capture flows. 2 req/sec
DocuSign eSignature API Business & Productivity OAuth Send, sign, and manage legally binding electronic signature envelopes programmatically. Free developer sandbox
Mailchimp Marketing API Business & Productivity API key Manage email lists, campaigns, and audiences for marketing automation. Free tier
Slack Web API Business & Productivity OAuth Post messages, manage channels, and build bots inside Slack workspaces. 3/min
Zoom API Business & Productivity OAuth Create and manage meetings, webinars, recordings, and users on Zoom. Per-endpoint caps
Calendarific API Business & Productivity API key Look up public, bank, and local holidays for 230+ countries and years. 1k req/mo
Nylas API Business & Productivity OAuth Unified API for email, calendar, and contacts across Gmail, Outlook, and IMAP providers. Free tier
Clearbit Logo API Business & Productivity No auth Fetch a company's brand logo image by domain name with a single request. Fair use
Microsoft Graph API Business & Productivity OAuth Unified gateway to Microsoft 365 data including Outlook mail, calendar, OneDrive, and Teams. 10k req
Dropbox API Business & Productivity OAuth Manage file storage, sharing links, and folder syncing in Dropbox. Free Basic account
Zapier NLA / Platform API Business & Productivity API key Trigger and manage automated workflows across thousands of connected business apps. Free tier
Cloudmersive Document API Business & Productivity API key Convert, edit, and process documents and spreadsheets (PDF, DOCX, XLSX) via REST. 800/mo
Intercom API Business & Productivity Token Manage customer conversations, contacts, and support tickets programmatically. 1k req/min