Co vs BDI
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Co
This app provides advanced word prediction and spelling support for students. It offers grammar-smart suggestions and access to millions of topic-specific dictionaries to aid in writing. Built-in text-to-speech functionality helps users review their work.
- Grammar-smart word prediction
- Millions of topic-specific dictionaries
- Flexspell™ technology for spelling errors
- Built-in text-to-speech
- Personalized vocabulary and settings
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Co:Writer® Universal app and third-party keyboard gives students easy access to word prediction on iPad, iPad Pro, iPhone, and iPod Touch. Students simply sign in to their Co:Writer Universal accounts to write with their personal settings and vocabulary. ABOUT CO:WRITER UNIVERSAL This version is for schools with a Co:Writer Universal license only. Users without a Co:Writer Universal license must purchase the Co:Writer app. HOW DOES CO:WRITER WORK? As letters are typed, Co:Writer predicts the intended word with a selection of word suggestions using powerful grammar-smart word prediction. These suggestions can be read aloud with a swipe. Selecting the intended word places it into the writing document. For feedback while writing (and after writing) built-in text to speech can be used to read letters, words, sentences, and the entire document. 4+ MILLION TOPIC-SPECIFIC DICTIONARIES Co:Writer has access to a main prediction dictionary (that includes core words) and Topic Dictionaries (that includes topic specific words). Co:Writer can access over 4 million topic-specific dictionaries which are activated based on the writing task. A small sampling of the variety of topic dictionaries: - America's Cup - Apple II - Compare and Contrast - Dinosaurs - Grumpy Cat - History of the Peloponnesian War - Mahatma Gandhi - My Dog - Pig Latin - Rolls-Royce Silver Ghost - SpongeBob SquarePants - Tommy (album) - Wonders of the World SPELLING SUPPORT Co:Writer handles the widest range of spelling mistakes through its Flexspell™technology including phonetic spelling and inventive spelling errors (letter omissions, word ending omissions, letter reversals, etc). Examples of how Co:Writer aides with phonetic and/or inventive spelling: Before Co:Writer The blk jargon flu over the bra lfnt. R u hpy to ce me? I no hw to nor the fone. After Co:Writer The black dragon flew over the gray elephant. Are you happy to see me? I know how to answer the phone. GRAMMAR SUPPORT Co:Writer bases its prediction off of proper grammar, and uses its understanding of grammar to accurately predict words within the framework of valid sentence structures. Examples of how Co:Writer aides with grammar: Dogs are furry. (noun, verb, adj.) - When you typed d-o, you get plural noun choices Three very mangy dogs ran down the street. (adj., adv., adj., noun, verb… etc.) - After typing three, very, mangy, you get plural noun choices, then you get plural verb tenses. OTHER FEATURES - Built-in Text to Speech - Export
BDI
This application assists in administering clinical assessments for child development. It offers guided digital support for scoring, timers, and reporting, functioning both online and offline. Users can manage student data and sync assessments for web-based access.
- Online and offline assessment administration
- Guided digital scoring assistance
- Basal and ceiling indicators
- Built-in timers
- Modular reporting options
- Student data management
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BDI-3 Mobile Data Solution (MDS) is an online and offline application to assist with the administration of the Battelle® Developmental Inventory 3rd Edition™ suite of products. The Battelle Developmental Complete, BDI-3 Screening Test, and the Battelle Early Academic Survey are clinical assessments that may be assessed through the BDI-3 MDS. The application provides guided digital assistance with the administration of each of the three products. The guided digital assistance includes basal and ceiling indicators, tallied scoring, built in timers, scoring rubrics, and modular reporting options. Within the application the user will be able to add students, administer all three types of BDI-3 assessments, and run reports both online and offline. It also allows the user to sync mobile record forms that they can then access on the riversidescore.com website.
Screenshots
Verdict
The clearest difference is rating: Co at 2.6 against BDI's 2.3. Co also leads on device support (3 vs 1) and iOS requirement (10.0 vs 13.0). BDI's advantage is update cadence (every 2 months vs every 4 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.
Co holds the better App Store score, 2.6 against 2.3. Both are backed by a comparable volume of ratings — 17 and 6 respectively.
Co ships an update every 4 months, BDI every 2 months. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.
| Parameter | Co | BDI |
|---|---|---|
| Price | Free | Free |
| Rating | 2.6 (17 ratings) — better | 2.3 (6 ratings) |
| Positive reviews | 8.3% of reviews | — |
| Number of ratings | 17 — better | 6 |
| Update frequency | Every 4 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPad |
| Requires iOS | 10.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 45 MB | 208 MB |
| Age rating | 4+ | 4+ |
| Developer | Don Johnston Incorporated | RiversideInsights |
Customer experience
Co
BDI
In-app purchases
Co
No in-app purchases
BDI
No in-app purchases









