Comparison

Casty vs Synapse

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

Head to head
About

Casty

Transform PDF documents into engaging podcasts with live transcripts and a built-in dictionary. Listen offline to educational content in Japanese or English after generation.

Highlights
  • Convert PDFs to podcasts
  • Live transcripts
  • Built-in dictionary
  • Offline listening
  • Japanese and English support
Features
Read full description

Convert PDF files into educational podcasts in Japanese or English Live transcript with built-in dictionary. Offline listening available after generation.

About

Synapse

Features
Read full description

Most apps are built to keep you scrolling. Synapse is built to make you stop, just once a day. It gives you a single fact, carefully written and drawn from the deepest corners of science and history. No feed, no infinite scroll, just one idea worth carrying with you, delivered whenever you choose. These are not trivia. Each fact is a small story: the slow evaporation of black holes, declassified Cold War experiments, animals that bend the laws of physics, words that carry the fingerprints of ancient civilizations. Written to be read in a minute, and remembered far longer. Ten worlds to explore: • Abysses & Cosmos: the physics of deep space and the ocean floor • Dark History: real, documented, and deliberately forgotten • Biohacking: the science of pushing human biology to its limits • Mind & Neuroscience: the strange architecture of perception • Weird Fauna: evolution's most brutal and brilliant solutions • Future Tech: what tomorrow's labs are building today • Etymology Lab: words as archaeological artifacts • Megastructures: impossible engineering, ancient and future • Geopolitics: borders that defy logic • Daily Science: the deep laws hidden in ordinary moments A streak grows with every day you show up, and when life gets in the way a shield protects what you have built, so a single missed day never erases weeks of curiosity. Every fact also carries a rarity, so the more you read, the richer your collection becomes: a private map of everything you have learned. Curiosity is better when it travels. Follow friends, compare streaks on the leaderboard, and share the facts that move you. Synapse asks for one minute a day. What you do with the idea is up to you.

Screenshots

Casty4 screens
Synapse4 screens

Verdict

The call

The clearest difference is iOS requirement: Casty at 15.1 against Synapse's 17. On price, update cadence, 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 2 days. The most recent releases landed on October 18, 2026 and October 13, 2026 respectively.

Scorecard1 real difference · 8 level
Casty versus Synapse: the parameters behind the verdict, then further details
ParameterCastySynapse
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyEvery 2 daysEvery 2 days
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.1 — better17
Further details — not scored
Size23 MB181 MB
Age rating4+12+
DeveloperWai Yip LiMattia Capomagi

In-app purchases

None

Casty

No in-app purchases

None

Synapse

No in-app purchases

Questions

Is Casty free?
Casty is free to download, with no in-app purchases.
Is Synapse free?
Synapse is free to download, with no in-app purchases.
Do Casty or Synapse have ads?
Neither Casty nor Synapse shows ads.
Which is updated more often, Casty or Synapse?
Casty ships an update every 2 days, and Synapse every 2 days. Most recently, Casty was updated on October 18, 2026 and Synapse on October 13, 2026.

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