String vs Vai Phone
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
String
Enhance customer engagement with a business SMS and voice platform. Organize your inbox, automate responses, and manage contacts efficiently. Send personalized messages to individuals or groups, and access your workflow from any device.
- Use existing or new phone numbers
- Organize inbox with sales funnel view
- Automated responses and auto-replies
- Contact management and CRM integrations
- 1-1, group, and mass messaging
- Templates and voicemail transcription
- Browser and mobile app access
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Boost your brand engagement with String’s intuitive business SMS marketing, text and voice. ANY PHONE NUMBER, EVEN LANDLINES Use your existing mobile or landline number with String. Select a new local number or upgrade to a vanity or toll free number of your choice. ORGANIZE YOUR INBOX Transform your inbox into a sales funnel or kanban board with various viewing, filtering and tagging options — Stay on top of your conversations and never miss a message again. POWERFUL MESSAGE MANAGEMENT Mark Unread and Archive — You love it for your emails, you’ll love it for your texts. STAY RESPONSIVE, 24/7 Amplify your interaction with automations and Auto-Replies — Respond to texts and missed calls on time, every time. TAP INTO ENDLESS POSSIBILITIES Contact Management & Integrations — Save important contact notes directly from the message thread. Capture contacts, import from your phone or computer,, automate workflows, integrate with tools you love (like your CRM, etc). REACH THE MASSES, OR JUST ONE Conversational, Groups or Mass Messaging — Respond directly with 1-1 messaging, message with a group,r or send personalized Mass Messages to multiple people at once, individually. BUILD A LOYAL CUSTOMER BASE Send promos, reminders and confirmations and never miss a lead, client or customer with Elite features like triggered Keyword Responses, and Auto-Replies. SAVE TIME Templates — No more copy-pasting the same message over and over. No time to listen to voicemail? View voicemail transcriptions in your inbox with visual voicemail. USE IT ANYWHERE Browser & Mobile Apps — Increase your workflow efficiency with access to String from your computer and mobile device. CALL FORWARDING & VOICE Separate your personal and professional calls with call forwarding and flexible voice settings. GOT QUESTIONS? Email our stellar support at support@joinstring.com. Find helpful articles, join our customer community and create tickets in our Help Center: https://help.joinstring.com/hc/en-us Terms of Service: https://www.joinstring.com/terms Privacy Policy: https://www.joinstring.com/privacy
Vai Phone
This app provides a full-featured Cloud PBX system, enabling users to make calls with a virtual phone system. Features include auto-attendant, music on hold, and call recordings, all for free.
- Cloud PBX system
- Auto Attendant
- Music on Hold
- Call Recordings
- Free to use
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Make calls with Vai Soft Phone and get a full featured Cloud PBX for free, like your Auto Attendant, Music on Hold, Call Recordings and more.
Screenshots
Verdict
The clearest difference is rating: Vai Phone at 5.0 against String's 3.5. Vai Phone also leads on review sentiment (100% vs 69%) and monetization model (free vs free with in-app purchases). String's advantage is ratings volume (62 vs 1). On price, ads, in-app purchases and device support 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.
Vai Phone holds the better App Store score, 5.0 against 3.5. That said, the two scores are not equally well evidenced: String has 62 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 69% of String's written reviews are positive against 100% of Vai Phone's.
String ships an update every 2 months, Vai Phone every 3 weeks. Both last shipped on October 24, 2026.
| Parameter | String | Vai Phone |
|---|---|---|
| Price | Free | Free |
| Rating | 3.5 (62 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 68.6% of reviews | 100.0% of reviews — better |
| Number of ratings | 62 — better | 1 |
| Update frequency | Every 2 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 15.0 | 9.0 — better |
| Further details — not scored | ||
| Size | 68 MB | 25 MB |
| Age rating | 4+ | 4+ |
| Developer | NumberBarn, LLC | Blast Technologies Pty Ltd |
Customer experience
String
Vai Phone
In-app purchases
String
No in-app purchases
Vai Phone
No in-app purchases
