Slab offers Free Trial, but Zapier does not.
Slab is designed for Medium Business and Small Business.
Zapier is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slab Starts at $35/Month when Billed Yearly whereas for Zapier Starts at $19.99/Month when Billed Yearly.
Some top alternatives to Slab includes Archbee, GitBook, Zoho Wiki, Drupal Wiki, LearnLode Enterprise, Matterial, TWiki, Wiki Valley, GoGoWorx and Kbee.
Some top alternatives to Zapier includes Pabbly Connect, Integrately, eZintegrations, Zoho Flow, ZapUp by 500apps, SaaS Integrator, Built.io Flow, Activepieces and ApiX-Drive.