Comparison

Prefix Dialer Pro vs Duoboard

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

Head to head
About

Prefix Dialer Pro

Automatically add dial codes or modify phone numbers before making calls. Ideal for office PBX systems, international dialing, or any situation requiring number reformatting. Sync rules across devices via iCloud.

Highlights
  • Automatic prefix and replacer rules
  • Contact integration
  • Clipboard detection
  • Manual number entry
  • Dial history
  • iCloud sync
  • Shake to open contacts
Features
Read full description

Prefix Dialer Pro lets you automatically prepend dial codes and transform phone numbers before placing a call — perfect for office PBX systems, international dialling, or any setup where numbers need a prefix. HOW IT WORKS Set up one or more prefix rules (e.g. "00" or "9") and replacer rules (e.g. strip the leading "+"). When you dial a number from your contacts, clipboard, or manually, every enabled rule is applied automatically. FEATURES • Contacts — pick any phone number directly from your contacts • Clipboard — detected automatically each time you open the app • Manual entry — type a number without opening your contacts • Dial history — quickly redial recent numbers • Shake to open contacts picker • iCloud sync — rules stay in sync across your devices • Up to 1 prefix and 1 replacer free; Go Pro for unlimited GO PRO A single one-time purchase unlocks unlimited prefixes and replacers and removes all ads. GREAT FOR • Staff who dial through a PBX (prepend 9 or 0 to get an outside line) • Frequent international callers (replace + with 00 or a country code) • Anyone whose phone system requires number reformatting before dialling

About

Duoboard

Features
Read full description

Duoboard puts your keyboard on one half of the open iPhone Duo and a productivity sidekick on the other. Or split the keys across both. LIVE EDIT No more cursor dance. Everything you've typed shows up right beside the keys, word by word, big enough to hit. Tap any word to swap it, fix it or retype it, without wrestling with the text in your app. Pinch two words to join them, or spread one to split it. In Half and in Split. HALF The keys on the screen you're holding, and your sidekick on the other: Live Edit, emoji with search, a number pad and symbols, your snippets and your clipboard. SPLIT One keyboard, a half under each thumb, like on iPad. Spread two fingers on the keys to split them, pinch to bring them back together, and drag the halves wider or narrower to fit your hands. Choose which keys show on which side. DUAL A whole keyboard under each thumb, split across the fold. FULL Or keep it classic, one keyboard across the whole screen. ONE-HANDED, WITHOUT THE FUSS • Sweep two fingers or flick the space bar toward a thumb, and the keyboard drops into Half under it. Sweep again to tuck the keys in for one hand. No holding the globe key, no menu. • On the closed Duo, flick the space bar toward your thumb for one-handed keys, and back for full width. • Drag the keyboard to any height and set its width, remembered for closed, open upright and open sideways. TYPES THE WAY YOU DO • Swipe typing, with suggestions as you swipe • Autocorrect that learns your words and your contacts' names, and reads the words before it • Next-word suggestions after a space • Missed spaces come apart: "itsjust" becomes "it's just" • Hold the space bar for a trackpad: the higher your thumb, the faster the cursor • Hold 123 for snake_case, kebab-case, camelCase or file paths • An optional number row, and a touch and hold on a letter for its accents • Emoji search that forgives typos • What you just copied waits in the suggestion bar, one tap to paste • Undo and redo in the suggestion bar • Set how fast the delete key repeats SNIPPETS AND CLIPBOARD Save the things you type all the time, your address, your email, a go-to reply, and send them with a tap. Duoboard can also keep what you copy, so it's there when you need it again. ON IPAD TOO Duoboard works on iPad too, Split and Live Edit included. PRIVATE Nothing you type leaves your device. No account, no ads, no tracking. DUOBOARD PRO The Full keyboard is free, with autocorrect, emoji, snippets and your clipboard. Duoboard Pro unlocks Half, Split, Dual, Live Edit and swipe typing: try it free for 7 days, then keep it with a one-time purchase. No subscription.

Screenshots

Prefix Dialer Pro4 screens
Duoboard4 screens

Verdict

The call

The clearest difference is update cadence: Duoboard at daily against Prefix Dialer Pro's every 8 months. Prefix Dialer Pro's advantage is iOS requirement (17.0 vs 26.0). On price, rating, ratings volume and ads 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. Prefix Dialer Pro sells 2 one-off in-app purchases and Duoboard sells 2 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for Prefix Dialer Pro against 5.0 for Duoboard. Both are backed by a comparable volume of ratings — 1 and 2 respectively.

UpkeepUpdate frequency

Prefix Dialer Pro ships an update every 8 months, Duoboard daily. Both last shipped on November 13, 2026.

Scorecard2 real differences · 7 level
Prefix Dialer Pro versus Duoboard: the parameters behind the verdict, then further details
ParameterPrefix Dialer ProDuoboard
PriceFreeFree
Rating5.0 (1 ratings)5.0 (2 ratings)
Number of ratings12 — better
Update frequencyEvery 8 monthsDaily — better
AdsNoNo
In-app purchasesYesYes
MonetizationFreemium—
DevicesiPhoneiPhone, iPad — better
Requires iOS17.0 — better26.0
Further details — not scored
Size4 MB27 MB
Age rating4+4+
DeveloperSOHO S & NPatrick Gatewood

Customer experience

Prefix Dialer Pro

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Duoboard

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

2 purchases

Prefix Dialer Pro

One-time2
  • Additional Set of 5 Prefixes and 5 Replacers$0.99
  • Set of 5 prefixes and 5 replacers$0.99
2 purchases

Duoboard

One-time2
  • 7-Day TrialFree
  • Duoboard Pro$1.99

Questions

Is Prefix Dialer Pro free?
Prefix Dialer Pro is free to download, with in-app purchases available.
Is Duoboard free?
Duoboard is free to download, with in-app purchases available.
Which has better reviews, Prefix Dialer Pro or Duoboard?
Prefix Dialer Pro and Duoboard are both rated 5.0 out of 5 on the App Store, from 1 and 2 ratings respectively.
Do Prefix Dialer Pro or Duoboard have ads?
Neither Prefix Dialer Pro nor Duoboard shows ads.
Which is updated more often, Prefix Dialer Pro or Duoboard?
Prefix Dialer Pro ships an update every 8 months, and Duoboard daily. Most recently, Prefix Dialer Pro was updated on November 13, 2026 and Duoboard on November 13, 2026.

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