OnSIP
OnSIP is a business phone system with mobile and desktop apps, web access, and multiple business numbers.
What OnSIP is
OnSIP is a business phone system with mobile and desktop apps, web access, and multiple business numbers. It includes an auto attendant, custom call routing, and voicemail transcription. The free plan supports up to 100 users and unlimited extensions, and includes Zendesk, HubSpot, and Odoo integrations. Free SIP accounts cannot dial regular phone numbers; paid plans provide a SIP-to-PSTN gateway service. Month-to-month contracts are available, with billing based on the users and features needed. Apps are available for Android, iOS, Windows, and Mac, and the browser softphone works in Chrome, Firefox, and Opera. A SIP address can have active registrations on up to 10 devices. Softphone apps provide end-to-end encryption, while desk-phone encryption is also available. OnSIP also lists an Admin Portal for setup, feature changes, payment and contact management, and invoices. Web and desktop video conferences support up to five people, and audio conference suites support up to 15 simultaneous callers.
Good
- Free plan supports up to 100 users and unlimited extensions.
- Includes auto attendant, custom call routing, and voicemail transcription.
- Free plan includes Zendesk, HubSpot, and Odoo integrations.
- Apps support Android, iOS, Windows, Mac, and web.
- Softphone apps provide end-to-end encryption.
Watch out
- Free SIP accounts cannot dial regular phone numbers.
- Video conferences support up to five people.
- Audio conference suites support up to 15 callers.
Who it suits
OnSIP suits businesses looking for a phone system with custom call routing, multiple business numbers, and apps across desktop and mobile. Its free plan may suit teams that do not need to call regular phone numbers from free SIP accounts.
Verdict
OnSIP combines business calling tools with a free tier and paid SIP-to-PSTN calling. Check the free plan's phone-number dialing limit and the conference participant caps against your needs.
Plans and prices
From OnSIP's own pricing page, checked 28 Sep 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free Plan | Free | Up to 100 users with unlimited extensions; phone-number dialing unavailable · 100 users |
| Unlimited | $18.95 a month | Minimum 5 users · 5 users minimum · 250 SMS/MMS per account · Minimum 5 users |
| Basic | $49.95 a month | Calling minutes and messaging not included · 3 auto attendants · 3 ring groups · 5 voicemail boxes · 1 call recording user · Calling minutes and messaging not included |
| Pay-as-you-go | $49.95 a month | Calling minutes not included · $49.95 per month, per account |
The facts
Each one read from OnSIP's own pages, with the date it was checked.
What it does
- Admin tools
- The Admin Portal supports setup, real-time feature edits, payment and contact management, and invoices.checked 28 Sep 2026
- Audio conference limit
- Audio conference suites support up to 15 simultaneous callers.checked 28 Sep 2026
- Auto attendant
- Yeschecked 22 Sep 2026
- Business customers
- OnSIP says it is trusted by more than 150,000 businesses.checked 28 Sep 2026
- Business numbers
- multiplechecked 22 Sep 2026
- Call encryption
- Softphone apps provide end-to-end encryption, with encryption also available for desk phones.checked 28 Sep 2026
- Call routing
- customchecked 22 Sep 2026
- CRM integrations
- Available integrations include HubSpot, Odoo, Zendesk, and an Open API.checked 28 Sep 2026
- HIPAA support
- The platform can be used by businesses to comply with HIPAA obligations.checked 28 Sep 2026
- Included users
- 5checked 22 Sep 2026
- Knowledge base
- The knowledge base contains setup articles, instructions, and video walkthroughs built over 20 years.checked 28 Sep 2026
- Media encryption
- OnSIP professional call-link media is encrypted using DTLS SRTP when both parties use the OnSIP app.checked 28 Sep 2026
- Paid from
- 18.95checked 22 Sep 2026
Money
- Billing model
- Month-to-month contracts are available, with payment based on needed users and features.checked 28 Sep 2026
- Free calling limit
- Free SIP accounts cannot dial regular phone numbers; paid plans offer SIP-to-PSTN gateway service.checked 28 Sep 2026
- Free integrations
- The free plan includes Zendesk, HubSpot, and Odoo integrations.checked 28 Sep 2026
- Free plan
- Yeschecked 22 Sep 2026
- Free plan limits
- The free plan supports up to 100 users and unlimited extensions.checked 28 Sep 2026
- SMS plan availability
- SMS and MMS are available on both Basic and Unlimited plans.checked 28 Sep 2026
Where it runs
- Browser support
- The browser softphone is available in Chrome, Firefox, and Opera.checked 28 Sep 2026
- Desktop and mobile apps
- Yeschecked 22 Sep 2026
- Device registrations
- A SIP address can have active registrations on up to 10 devices.checked 28 Sep 2026
The company
- Founded
- 2004checked 28 Sep 2026
- Headquarters
- Sunnyvale, California, United Stateschecked 28 Sep 2026
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