OnSIP review
A flexible SIP-friendly phone system with a free plan and paid PSTN calling.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
OnSIP is a cloud-based business phone system for organizations that need hosted PBX capabilities without on-premises telephone infrastructure. It combines business calling, auto attendants, business-hour routing, ring groups, queues, voicemail-to-email, SMS/MMS, video calling, conferencing, call recording, and call-detail records. Teams can access it through web, Windows, macOS, iOS, Android, a Chrome extension, open APIs, compatible SIP devices, and browser-based administration. Its free plan is especially suited to teams that primarily need SIP-to-SIP communication and web call links.
Pricing is structured around a free plan and two paid monthly options. The Free Plan includes SIP-to-SIP voice and video calling, web call links and HTML buttons, up to 100 users, and integrations with Zendesk, HubSpot, and Odoo. Unlimited costs $18.95 per user per month and adds unlimited standard calling minutes, unlimited auto attendants, unlimited ring groups, voicemail and voicemail-to-email, included VoIP phones, and 250 SMS/MMS messages per account. Basic costs $49.95 per account per month and provides pay-as-you-go calling, one announcement, three auto attendants, one call-recording user, three ring groups, and five voicemail boxes with voicemail-to-email. A 30-day free trial is also available.
OnSIP fits teams that want SIP hosting, multiple business numbers, custom call routing, and access across desktop and mobile apps. Its open API supports additional integration work, while the listed direct integrations cover HubSpot, Zendesk, and Odoo. The free plan is not suitable for ordinary telephone-number calling, so teams needing PSTN access should choose a paid plan. Organizations seeking native voicemail transcription or a broader listed integration ecosystem may prefer an alternative. For SIP-friendly teams that value hosted PBX controls and a low-cost entry point, OnSIP offers a focused combination of calling, messaging, routing, and conferencing features.
OnSIP pros and cons
- Where it wins
- Free SIP-to-SIP voice and video calling for up to 100 users
- Routing, queues, ring groups, conferencing, and call recording
- Web, desktop, mobile, Chrome, API, and SIP device access
- Where it doesn't
- Free plan cannot dial ordinary telephone numbers
- Listed integrations are limited to HubSpot, Zendesk, and Odoo
- Voicemail transcription relies on PhoneTag or Phonewire integrations
OnSIP fact sheet, pricing and score →
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