OnSIP vs ESI eMobile
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
OnSIP
This app extends your business phone system to your mobile device, enabling HD voice and video calls, contact monitoring, and voicemail management. Stay connected with clients and colleagues from anywhere, without needing extra hardware.
- HD voice and video calls
- Voicemail management
- Contact availability monitoring
- Call history
- Remote work connectivity
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OnSIP brings your business phone to you, whether you're at the office, at a client's site, or working remotely. Connect with customers, partners, vendors, and coworkers from your OnSIP account on your iPhone. With OnSIP, you can take advantage of standard business phone features without the additional hardware. Make and receive HD voice and video calls, monitor contact availability, check recent call history, and manage your voicemail in one simple interface.
ESI eMobile
This business phone system app extends your office phone capabilities to your mobile device. Access voicemails, contacts, call recording, and manage extension preferences on the go. Communicate with colleagues and the outside world as if you were at your desk.
- Voicemail access
- Coworker directory
- Personal contacts
- Call recording
- Extension preference management
- Conference calls
- Coworker availability
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ESI’s eMobile™ application for iOS brings your eSIP Evolution Series™ business phone system extension with you, wherever you may be! Access voicemails, coworkers directory and personal contacts, and call recording features from anywhere. Manage your extension preferences and even conference calls from the palm of your hand. See your coworkers’ availability and easily communicate with them, as well as the rest of the world, as if you were sitting in front of your ESI desk phone. *Must be used with ESI’s eSIP Evolution Series™ phone system - e-series or x-series. *Contact your Certified ESI Partner for more information.
Screenshots
Verdict
The clearest difference is rating: ESI eMobile at 3.0 against OnSIP's 2.4. ESI eMobile also leads on review sentiment (33% vs 9%) and iOS requirement (11.0 vs 17.4). OnSIP's advantage is update cadence (every 2 months vs every 7 months) and ratings volume (67 vs 12). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
ESI eMobile holds the better App Store score, 3.0 against 2.4. That said, the two scores are not equally well evidenced: OnSIP has 67 ratings behind it against 12, so its average is the more settled of the two. Written reviews point the same way: 9% of OnSIP's written reviews are positive against 33% of ESI eMobile's.
OnSIP ships an update every 2 months, ESI eMobile every 7 months. The most recent releases landed on September 15, 2026 and June 1, 2026 respectively.
| Parameter | OnSIP | ESI eMobile |
|---|---|---|
| Price | Free | Free |
| Rating | 2.4 (67 ratings) | 3.0 (12 ratings) — better |
| Positive reviews | 8.7% of reviews | 33.3% of reviews — better |
| Number of ratings | 67 — better | 12 |
| Update frequency | Every 2 months — better | Every 7 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad | iPhone, iPod |
| Requires iOS | 17.4 | 11.0 — better |
| Further details — not scored | ||
| Size | 26 MB | 70 MB |
| Age rating | 4+ | 4+ |
| Developer | OnSIP | Estech Systems, Inc |
Customer experience
OnSIP
ESI eMobile
In-app purchases
OnSIP
No in-app purchases
ESI eMobile
No in-app purchases
