# Build Your Own Calendly Alternative - Tool: Build Your Own SaaS Alternative - Last updated: May 2026 ## TL;DR Calendly is the leading scheduling platform with 20M+ users, charging $1,920/yr for 10 seats on Teams — just to book meetings. Cal.com (41,900 GitHub stars, AGPL-3.0) provides near feature-parity for free and is the ideal fork base. A custom build takes 4–8 weeks at $20K–$50K and breaks even in 4–9 months against a 25-seat Teams deployment costing $4,800/yr. ## Frequently asked questions ### How much does it cost to build a Calendly alternative? Building a Calendly alternative costs $20K–$50K if you fork Cal.com as your base, or $60K–$120K if building from scratch. The Cal.com fork path is strongly recommended — it saves 3–5 months of calendar integration work. The main cost drivers are calendar OAuth integration, timezone handling, and reminder pipeline infrastructure. ### How long does it take to build a Calendly clone? 4–8 weeks for an MVP built on Cal.com with customizations. 3–5 months if building from scratch with a multi-calendar sync engine, booking flow, reminder pipeline, and team scheduling features. Cal.com is the fastest path to production — the core scheduling engine is already battle-tested at scale. ### Are there open-source Calendly alternatives? Yes — Cal.com (41,900 GitHub stars, AGPL-3.0) is the strongest option with near feature-parity to Calendly Teams. It's actively maintained with frequent releases. Rallly (~5.1K stars, AGPL-3.0) is a simpler group polling scheduler for finding meeting times. Easy!Appointments (~3.5K stars, GPLv3) works for traditional appointment businesses but uses a PHP stack. ### Can RapidDev build a custom Calendly alternative? Yes — RapidDev has built 600+ applications including scheduling tools and multi-tenant SaaS platforms. We typically recommend the Cal.com fork approach for a 4–8 week delivery timeline. Visit rapidevelopers.com/contact for a free consultation. ### Does Cal.com require a commercial license? Cal.com is AGPL-3.0 licensed. Self-hosting for internal use (your own team) is free. If you're building a SaaS product that you sell to others using Cal.com's code, AGPL-3.0 requires you to open-source your modifications or obtain a commercial license from Cal.com Inc. Commercial license pricing is available at cal.com/enterprise. ### What is the hardest part of building a scheduling tool? Multi-provider calendar OAuth and timezone handling are the trickiest engineering challenges. Google Calendar's API has rate limits (1,000,000 requests/day per project) that require smart caching. Microsoft Graph OAuth token refresh has edge cases that cause availability sync failures. Timezone-aware slot generation must handle DST transitions, half-hour offsets (India, Iran), and user-versus-event timezone mismatches. ### Can I import my existing Calendly data? Calendly does not offer a data export API for historical booking data. You can export future bookings via the Calendly API (events endpoint) and migrate event types by recreating them manually or scripting the configuration. Cal.com does not have a native Calendly importer — plan for manual recreation of event type configurations during migration. ### At what team size does building make financial sense? At 25 seats on Calendly Teams ($4,800/yr), a $20K–$50K custom build breaks even in 4–10 months — the strongest ROI case in the productivity category. Below 10 seats ($1,920/yr), the SaaS cost is low enough that self-hosting is rarely worth it unless you need white-labeling or custom routing logic that Calendly doesn't support. --- Source: https://www.rapidevelopers.com/clone/calendly © RapidDev — https://www.rapidevelopers.com/clone/calendly