Pendulum vs DJOLT
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Pendulum
This app helps you manage your pen pal relationships by tracking correspondence. Record when you send and receive letters, note writing materials, and set reminders to stay in touch. Sync your data across devices for seamless management.
- Track sent and received letters
- Record pen, ink, and paper used
- Set reminders to write and post
- Monitor letter delivery times
- iCloud sync across devices
Read full descriptionHide full description
Pendulum - keep track of your pen pals! • Add your friends, record when you send them letters or they send something to you. See how long it takes for your letters to arrive! • Record what pen, ink, and paper you used to write to each person, to keep the variety going each time you write. • Reminders to write back, or to post letters you've written but have sat by the front door for ages; you won't forget to stay in touch again. • Sync via iCloud, so you can keep up to date regardless of what device you have to hand.
DJOLT
Read full descriptionHide full description
DJOLT is built for the maritime, cruise, and yachting industries but adapts seamlessly to a variety of onshore settings. Designed to deliver high-priority alerts directly to your device within a local network, DJOLT eliminates the need for uninterrupted internet access, ensuring reliability in environments where connectivity may be limited. DJOLT operates with a locally installed DJOLT Server, using Local Push Connectivity, to ensure alert delivery even if the app is closed or running in the background. Supported Features: - View active and historical alerts, with timestamps for received and acknowledged alerts. - Acknowledge alerts within the app or by long-pressing a banner notification. - On/Off Duty setting to manage availability. - Critical Alerts that bypass Silent Mode, preventing missed notifications for high-priority situations. - Acknowledge and silence an alert for all recipients when acknowledged by a single user. - Adjustable alert volume. - Test notifications for setup verification. While optimized for maritime use, DJOLT’s on-premises functionality makes it equally effective for industrial facilities, manufacturing plants, and security systems, supporting reliable oversight and timely response to critical situations.
Screenshots
Verdict
The clearest difference is in-app purchases: DJOLT at none against Pendulum's 5. On price, update cadence, ads 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. Pendulum sells 5 one-off in-app purchases. DJOLT asks for nothing beyond the download.
Pendulum ships an update every 9 days, DJOLT fortnightly. The most recent releases landed on September 10, 2026 and September 9, 2026 respectively.
| Parameter | Pendulum | DJOLT |
|---|---|---|
| Price | Free | Free |
| Rating | 4.2 (16 ratings) — better | — |
| Positive reviews | 66.7% of reviews | — |
| Number of ratings | 16 — better | — |
| Update frequency | Every 9 days — better | Fortnightly |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 — better | 17.5 |
| Further details — not scored | ||
| Size | 5 MB | 69 MB |
| Age rating | 4+ | 4+ |
| Developer | Benjamin Cardy | Matthew Johl |
In-app purchases
Pendulum
- Extra Fine Tip$0.99
- Fine Tip$1.99
- Medium Tip$3.99
Show 2 moreShow fewer
- Broad Tip$5.99
- Stub Tip$9.99
DJOLT
No in-app purchases









