Start with the job, not the logo wall.
HollyHR has a documented API, outbound webhooks, hosted MCP, Google sign-in and calendar feeds. It does not call an API recipe a native integration.
Slack
API and webhook recipes for leave notifications; no native Slack app yet.
Read it →Current statusGoogle Workspace
Google sign-in plus an iCal subscription for who's-away; no directory sync yet.
Read it →Current statusMicrosoft 365
Microsoft work-account sign-in plus an Outlook calendar subscription; no directory sync yet.
Read it →Current statusXero
Export or API hand-off to Xero; no native payroll sync yet.
Read it →Current statusSage
Export or API hand-off to Sage; no native payroll sync yet.
Read it →Current statusZapier
Build from HollyHR's API and webhooks; no listed Zapier app yet.
Read it →Current statusStripe
Stripe powers HollyHR billing; it does not sync your company's payments into HR.
Read it →Building something specific?
Read the developer documentation first. It describes the real authentication, scopes, resources and webhook surface rather than a marketing approximation.