I tried to start tracking my mood properly this year. The advice everyone gives is the same: log it daily, look at the patterns, adjust. Fine. So I went looking for the app.
Daylio is the one everyone points to, and it's genuinely good. Clean, fast, the design is years ahead of most of the category. I used it for a couple of weeks. Then I went to look at the actual stats, the part that's the whole point, and hit a wall.
The interesting graphs are premium. Mood-by-weekday, the activity correlations, the longer trends. That's the data that tells you something. And it sits behind a subscription.
What Daylio actually costs
I want to be fair here, so I checked the current numbers rather than going off memory. Daylio has a real free tier, and it works. But Daylio Premium runs $4.99 a month or $35.99 a year, with a 7-day trial. (They run discounts on the annual plan fairly often.)
The free version is not crippled, but the things it locks are the things I cared about. When you're on free, you lose:
- Advanced stats
- Moods and goals past a free limit
- Reminders past a free limit
- Automatic backups
- PDF export
- Premium themes
So the deal is: the tracking is free, the understanding is paid. For a tool whose entire value is helping you see your own patterns, paywalling the patterns felt backwards to me. I wrote more about that specific objection in why mental-health tracking behind a subscription is backwards.
To Daylio's credit on privacy: they don't send your entries to their servers, and backups go to your own Google Drive or iCloud over encrypted channels. That part is good and I'm not going to pretend otherwise.
So I built SoulSync
I'm a developer, and I had a stubborn opinion, which is a dangerous combination. I built SoulSync, a mood tracker and journal with two rules: nothing behind a paywall, and nothing leaves your device.
It's React Native and Expo, TypeScript in strict mode, 333 passing tests, and it's GPL-3.0. Open source from the start. The code that holds your most private data is public, so you can read it instead of trusting a sentence on a marketing page.
Every entry is stored in a SQLite database on your phone. Photos too. There is no account to create, no server to connect to, no cloud bucket sitting somewhere with your feelings in it. I go deeper on the architecture in a mood tracker shouldn't need an account or the cloud.
An honest comparison
Here's the side by side. I've kept it to things I can actually back up.
| SoulSync | Daylio | |
|---|---|---|
| Price | Free (open source) | Free tier; Premium $4.99/mo or $35.99/yr |
| Advanced stats | Included | Premium |
| Activity correlation | Included | Premium |
| Data export | JSON, included | PDF export is Premium |
| Themes | 5, all free | Some themes are Premium |
| Entries stored on device | Yes (SQLite) | Yes (cloud backup is optional) |
| Open source | Yes, GPL-3.0 | No |
| Platforms | Android (free APK) | Android and iOS |
Daylio wins on polish and platform reach. It's been worked on for years by a team, and it shows. If you're on iPhone, it's your option and SoulSync isn't, yet.
SoulSync wins on the two things I built it for: you pay nothing for the full feature set, and the code is open so the privacy claim is checkable.
What open source plus local-first actually buys you
Two phrases get thrown around a lot. Here's what they mean in practice, not in pitch.
Local-first means the app works with no network, the data is a file you own, and there's no account that can be locked or breached. If my server vanished tomorrow, your SoulSync history wouldn't even notice. There is no server.
Open source means the privacy story isn't a promise, it's source code. You can read exactly where your data goes, which is nowhere, and so can anyone else. It also means the app can't quietly add tracking in a future update without it being visible in the commits.
And it means free without a catch. There's no premium tier waiting to be unlocked because there's no business model that depends on one. The whole app is the free version because there is no other version.
If you want to try it
SoulSync is Android-only for now. Download the APK from the latest GitHub release and log your first entry. It stays on your phone.
If you find a bug or want a feature, the repo is right there: github.com/Antimatter543/mood-tracker.