T vs Cardzilla
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
T
This app enables individuals who are Deaf, Hard of Hearing, DeafBlind, or have a Speech Disability to make and receive relay calls using text over the internet. It connects users with a qualified relay operator and offers features like an integrated contact list and call history.
- Text-based relay calls
- Integrated contact list
- Call history
- Access to live customer care
- Available on wireless networks
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IP Relay, provided by T-Mobile for iOS devices, is a no cost internet-based telecommunications Mobile app available for people who are Deaf, Hard of Hearing, DeafBlind, or who have a Speech Disability who can make and receive relay calls and communicate using text on iOS 9 or higher, including iPad devices. IP Relay app is also available on wireless networks. Connect with a qualified relay operator via IP Relay. Features include integrated contact list, call history, and access to live customer care. Available only in USA and US territories. International calls will either be blocked or terminated. Registration is required to use this app. If no data plan service selected, casual data charges may apply. Learn more at t-mobile.com/IPRelay. Although IP Relay can be used for emergency calling, such emergency calling may not function the same as traditional 911/E911 services. By using the IP Relay app for emergency calling you agree that T-Mobile is not responsible for any damages resulting from errors, defects, malfunctions, interruptions, or failures in accessing or attempting to access emergency services through IP Relay whether caused by the negligence of T-Mobile or otherwise.
Cardzilla
Display your messages in large, clear text for easy reading across distances. This app offers a no-scroll design that automatically resizes text as you type, saving all your cards automatically. It's ideal for silent communication or grabbing attention without sound.
- Large and clear text display
- Automatic text resizing
- No scroll design
- Automatic card saving
- Save favorite messages
- Quick swipe navigation
- Shake to save and erase
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A fast & simple way to display your messages in large text. Communicate across distances. Pass messages silently. Grab attention when sound isn't an option! CARDZILLA Features • Large & clear text, easy to read. • No scroll design, text automatically resizes as you type! • All cards are automatically saved, never lose anything. • Save favorite messages for quick access. • Quick navigation with swipe interface. • Shake to quickly save-and-erase! CARDZILLA is built for speed and ease of use. Just start typing as soon a blank card appears. Text will resize as you type, no scrolling ever!
Screenshots
Verdict
The clearest difference is review sentiment: Cardzilla at 91% against T's 16%. Cardzilla also leads on rating (4.5 vs 3.1) and update cadence (every 4 weeks vs every 3 months). On price, ratings volume, 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Cardzilla holds the better App Store score, 4.5 against 3.1. Both are backed by a comparable volume of ratings — 88 and 87 respectively. Written reviews point the same way: 16% of T's written reviews are positive against 91% of Cardzilla's.
T ships an update every 3 months, Cardzilla every 4 weeks. Both last shipped on October 23, 2026.
| Parameter | T | Cardzilla |
|---|---|---|
| Price | Free | Free |
| Rating | 3.1 (88 ratings) | 4.5 (87 ratings) — better |
| Positive reviews | 16.4% of reviews | 91.1% of reviews — better |
| Number of ratings | 88 — better | 87 |
| Update frequency | Every 3 months | Every 4 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 16.6 | 13.0 — better |
| Further details — not scored | ||
| Size | 15 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | T-Mobile | Tim Kettering |
Customer experience
T
Cardzilla
User reviews
T
From 88 App Store ratingsWhat we love
- 👍 Accessible for DeafBlind
- 👍 Can save conversations
- 👍 Live operator accuracy
- 👍 App updated for easier call shifting
- 👍 Good for Spasmodic Dysphonia
Room to improve
- 🐛 Lots of bugs
- 🐛 Calls get dropped
- 🐛 Fake number calls
- 🐛 App not updated
- 🐛 App broken, cannot make calls
Cardzilla
From 87 App Store ratingsWhat we love
- 👍 Simple and intuitive interface
- 🚀 Fast and efficient communication
- 💡 Invaluable for users with speech/hearing impairments
- 👍 Large, readable text display
- 👍 Automatic saving of history
Room to improve
- 🐛 Speech-to-text can be slow
- 🐛 Microphone turns off too quickly
- 🐛 Lack of language translation
- 🐛 No clear way to contact developer
- 🐛 Shake-to-erase can be accidentally triggered
Bugs and requests
T
Reported bugs
50 issues- App still has LOT of bugs
- Calls get dropped
- Line is busy error
- Hackers fake number calls
- App hasn't been updated
Show 45 moreShow fewer
- Doesn't work at all now
- Cut out during call
- Tried to recall but didn't work
- Phone number in use error
- Call connects then drops
- CAs typing too many 'xxxx'
- Transcribes caller's words to email
- Password is wrong (works elsewhere)
- Cannot verify identity
- New version confusing
- Cannot use microphone on keyboard to dictate
- Cannot register, couldn't verify details
- App does not connect to relay
- Microphone doesn't work for voice to text
- App doesn't work
- Doesn't seem to work when trying to answer call
- Does not list incoming call
- Opening from notification screen, number not listed
- Buggy, doesn't cooperate with system accessibility settings
- Scrolling is buggy
- Incoming text bounces below window
- Incoming call window doesn't expand
- Incoming calls don't always answer
- System often cuts off users
- Performance gets worse
- Takes several minutes for messages to get through
- Never able to complete important calls
- Whenever I get a call, accept call does nothing
- No vibration or sound notification for incoming calls
- App requires upgrade but upgrade doesn't fix error
- Unable to type anything to answer call
- Can't see who called
- Cannot answer calls
- Number flashes briefly
- Cannot forward number
- Forwarding isn't supposed to work
- App crashes when opening
- Keyboard covers text box
- Login doesn't work
- Login not valid
- Username creation fails
- Nobody can hear me
- Login/password doesn't work on app
- Verification review takes too long
- Favorites screen doesn't work
Requested features
10 requests- Ability to report spam callers
- Send words automatically as I type
- Add ability to block numbers
- Option to subscribe to spam call blocking service
- Make browser and app interfaces more similar
Show 5 moreShow fewer
- Sound alerts for incoming calls
- Way to read messages left by caller
- Voicemail for missed calls
- Copy and paste phone numbers into dial screen
- Alphabetized phone book
Cardzilla
Reported bugs
3 issues- Crashes on two-finger swipe up (iPad Air 2, iOS 11.2)
- App no longer has mic icon (reported in 2019)
- Notes lost when switching apps (reported in 2020, contradicted by other reviews)
Requested features
15 requests- On-screen keyboard visibility toggle
- Adaptive text size options (fixed or auto-overflow)
- Language translator
- Setting for microphone to stay on
- Option to disable shake-to-erase
Show 10 moreShow fewer
- Dark mode option
- Ability to set notes to 'scroll'
- Option to contact developer
- Add time/date stamps to saved notes
- More color options for background/text
- Support for Apple Watch
- Offline speech-to-text functionality
- Yellow background option for DeafBlind users
- Option to make text size smaller
- Improve text size scaling for longer inputs
In-app purchases
T
No in-app purchases
Cardzilla
No in-app purchases
