Comparison

String vs Callcentric SMS

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read full description

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

About

Callcentric SMS

Send and receive SMS messages using your Callcentric phone numbers. This app offers real-time messaging, contact list integration, and dark mode support. It requires an active Callcentric account and an SMS Access Plan.

Highlights
  • Real-time SMS messaging
  • Dark Mode support
  • Contact list integration
  • Multiple number support
  • Manage SMS functionality per number
  • Multi-account support
  • Customizable default SMS number
Features
Read full description

The completely new Callcentric SMS app has been re-designed to provide the best SMS experience with your Callcentric account. SMS is supported on ALL of our US and Canada Numbers! Getting started is easy, all you need to do is activate one of our SMS Access Plans on your Callcentric account and install this app on your iOS device. That's it! REQUIRED TO USE THIS APP • An active Callcentric VoIP service account • Callcentric SMS Access Plan & US/Canada phone number NOT CURRENTLY SUPPORTED • MMS Messaging (group messages, attachments, etc) • SMS Messaging with International numbers (outside of US/Canada) FEATURES & HIGHLIGHTS • SMS Messaging in real-time • Dark Mode support for easier viewing • Option to use the Contact List in your device • Support for messaging with multiple numbers via a single interface • Enable/Disable SMS functionality on any of your US, Canada, or toll-free numbers • Store the username and settings for multiple accounts for fast switching between logins • Show your SMS number (the number you are sending from) in the conversation list - useful when you use multiple SMS numbers. Enable in settings • Set a default SMS number to use for sending messages or manually choose the SMS number you want to use on a per message basis. Enable in settings Access to Contacts (optional): Used to let you select a contact to send an SMS to, and properly show name information on messages received with an entry in your iPhone/iPad contacts. Your Contact list will NEVER to be uploaded to Callcentric. Data is used locally within the app. We do not have access to your Contacts outside of the app. Notifications (optional): We use push notifications to notify you of incoming SMS messages in real-time when the app is in the background. WARNING: if you do not enable notifications you will not receive notice of new incoming SMS messages until the next time you open the app.

Screenshots

String4 screens
Callcentric SMS4 screens

Verdict

The call

The clearest difference is rating: Callcentric SMS at 4.7 against String's 3.5. Callcentric SMS also leads on monetization model (free vs free with in-app purchases) and update cadence (every 3 weeks vs every 2 months). On price, review sentiment, ads and in-app purchases 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Callcentric SMS holds the better App Store score, 4.7 against 3.5. Both are backed by a comparable volume of ratings — 62 and 209 respectively. Written reviews point the same way: 69% of String's written reviews are positive against 73% of Callcentric SMS's.

UpkeepUpdate frequency

String ships an update every 2 months, Callcentric SMS every 3 weeks. The most recent releases landed on November 2, 2026 and November 11, 2026 respectively.

Scorecard4 real differences · 6 level
String versus Callcentric SMS: the parameters behind the verdict, then further details
ParameterStringCallcentric SMS
PriceFreeFree
Rating3.5 (62 ratings)4.7 (209 ratings) — better
Positive reviews68.6% of reviews72.7% of reviews — better
Number of ratings62209 — better
Update frequencyEvery 2 monthsEvery 3 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better16.6
Further details — not scored
Size68 MB49 MB
Age rating4+17+
DeveloperNumberBarn, LLCCallcentric, Inc.

Customer experience

String

All ratings62 ratings
Positive64.5%
Neutral1.6%
Negative33.9%
Written reviews35 reviews
Positive68.6%
Neutral2.9%
Negative28.6%

Callcentric SMS

All ratings202 ratings
Positive92.6%
Neutral4.5%
Negative3.0%
Written reviews11 reviews
Positive72.7%
Neutral18.2%
Negative9.1%

Bugs and requests

String

Reported bugs

22 issues
  • Calls drop within seconds
  • Line cuts out completely
  • Website loads to a white screen
  • App loads message threads out of order
  • Tapping into a thread does not load any part of the conversation
Show 17 more
  • Sending a message in the thread works, but the thread doesn’t load
  • Tapping a thread loads an entirely different number/contact at the top
  • Push notification badges don’t clear
  • Text threads are slow to update and sometimes show off screen
  • No where to sign up on the app
  • Lost account after uninstall/reinstall
  • No one to talk to for support
  • iTunes account debited without loading sign-in page
  • Stuck on unpaid account, cannot log out
  • Missed calls do not show up on the main log panel
  • Voicemails will not play in app
  • No iPad App
  • Web app directs back to mobile app
  • No attention to detail in integrations
  • Phone number picker is super limited
  • No filtering by numbers
  • Requires payment to see the app

Requested features

18 requests
  • Improve mobile app stability
  • Fix website loading issues
  • Ensure message threads load correctly
  • Improve contact loading accuracy
  • Fix push notification badge issues
Show 13 more
  • Improve text thread update speed
  • Enhance call stability
  • Improve customer support responsiveness
  • Provide in-app sign-up
  • Allow account recovery
  • Offer refunds
  • Implement missed call notifications
  • Ensure missed calls appear in logs
  • Enable voicemail playback in app
  • Develop an iPad app
  • Improve sign-up process
  • Add more phone number filtering options
  • Integrate with CRM software like HubSpot

Callcentric SMS

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

String

No in-app purchases

None

Callcentric SMS

No in-app purchases

Questions

Is String free?
String is free to download, with no in-app purchases.
Is Callcentric SMS free?
Callcentric SMS is free to download, with no in-app purchases.
Which has better reviews, String or Callcentric SMS?
Callcentric SMS is rated higher. String averages 3.5 out of 5 from 62 ratings, while Callcentric SMS averages 4.7 from 209 ratings.
Do String or Callcentric SMS have ads?
Neither String nor Callcentric SMS shows ads.
Which is updated more often, String or Callcentric SMS?
String ships an update every 2 months, and Callcentric SMS every 3 weeks. Most recently, String was updated on November 2, 2026 and Callcentric SMS on November 11, 2026.

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