For almost all teams, buying is significantly faster and cheaper than building - especially when you factor in ongoing maintenance, cross-platform compatibility, and the ancillary features you would also need to build.

What "building it yourself" actually involves

Calendar subscription infrastructure requires:

• Generating valid iCal (.ics) feeds with correct RFC 5545 syntax
• Hosting the feed at a stable, publicly accessible URL
• Handling timezone conversions, DST transitions, and recurring event rules
• Supporting platform-specific quirks for Google Calendar, Apple Calendar, Outlook, and Yahoo
• Building a subscriber management system (subscribe, unsubscribe, block)
• Ongoing maintenance as calendar platform standards and URL formats change

RSVP infrastructure requires:

• A form builder with custom field types
• Email sending infrastructure with SPF/DKIM setup for deliverability
• A confirmation and reminder email sequencing system
• Attendee data storage, export, and management
• Capacity management and seat limits

Combined estimated development cost: $15,000-$40,000 initial build, plus $3,000-$8,000/year in ongoing maintenance and developer time.

What buying (AddEvent) costs

AddEvent Small Business: $29/month ($348/year) - includes subscription calendars, RSVP forms, Add to Calendar buttons, embeddable widgets, email notifications, analytics, and Zapier integration.

When building might make sense

• You need deep custom behavior that no SaaS tool supports (e.g., calendar feeds derived from highly complex proprietary business logic)
• Your engineering team already has the infrastructure and the marginal cost is near zero
• You have strict data residency requirements that preclude using external SaaS for attendee data

The build-vs-buy checklist

Before building, ask: Does a paid solution cover your requirements at a cost lower than development? For calendar and RSVP tooling, the answer is almost always yes.