Blog

Engineering deep-dives, product stories, and lessons from building AI-powered apps.

cortisuse casesoffline AI

10 Things You Can Do With AI Without Internet

No Wi-Fi? No problem. Here are 10 practical things you can do with an on-device AI assistant when you're offline — on a plane, in the subway, or camping in the middle of nowhere.

Apr 20, 20264 min read
cortistutorialShortcuts

5 AI Shortcuts That Work Without Internet on iPhone

Step-by-step guide to building 5 powerful Apple Shortcuts that use on-device AI. Summarize webpages, translate text, draft emails, and more — all offline.

Apr 20, 20265 min read
roundupAI apps

Best Free AI Apps for iPhone in 2026 — No Subscription Required

A curated list of the best free AI apps for iPhone in 2026. We cover on-device chat, search, writing assistants, and built-in Apple features — with honest pros and cons for each.

Apr 20, 20265 min read
persona-aitutorialAI

From Character to Episode: AI Content Creation Workflow

A step-by-step walkthrough of creating an AI-generated episode from scratch — character design, consistent shots, AI voice, and assembly. What used to take months now takes hours.

Apr 20, 20266 min read
wedding-aitrendsAI

How Couples Are Using AI for Wedding Planning in 2026

AI is reshaping how couples plan weddings — from venue visualization to dress try-on to budget optimization. Here's what's actually working and where Wedding AI fits in.

Apr 20, 20265 min read
subtrackerpersonal financedata

How Much Do You Really Spend on Subscriptions? The Numbers Will Surprise You

The average American spends $219/month on subscriptions and underestimates the number by 2-3x. Here's how subscription fatigue happens, what the data says, and how to take back control.

Apr 20, 20265 min read
food-symptom-detectivehealthIBS

Managing IBS with a Food Diary: What Actually Works

IBS affects 10-15% of the global population, but most people track triggers wrong. Here's why a structured food diary beats guesswork — and how Food Symptom Detective helps you do it right.

Apr 20, 20265 min read
cortisprivacycomparison

What Data Do AI Apps Actually Collect? A Factual Comparison

A straightforward look at what ChatGPT, Claude, Gemini, and on-device AI apps collect, store, and use. No fear-mongering — just facts with sources.

Apr 20, 20265 min read
pixiwellnessgaming

Why Pixel Art Coloring Is the Perfect Stress Relief

Research shows coloring reduces anxiety. Pixel art adds structure and flow state. Here's why pixel coloring apps like Pixi are becoming a go-to for stress relief — and what the science says.

Apr 20, 20265 min read
cortiscomparisonon-device AI

Cortis vs Google AI Edge Gallery: Two Approaches to On-Device AI

An honest comparison of Cortis and Google AI Edge Gallery — two on-device AI apps with very different goals. One is a tech demo, the other is built for daily use with Siri, Shortcuts, and system integration.

Apr 19, 20265 min read
persona-aiproductAI

Create AI Characters That Actually Look Consistent

The biggest problem with AI-generated characters is they look different every time. Persona AI uses LoRA training to keep your characters recognizable across generations — then lets you build full episodes with them.

Apr 19, 20265 min read
wedding-aiproductAI

Dream Wedding Photos Before the Wedding Day

Preview what your wedding photos would look like at dream venues around the world — Santorini, Paris, Bali — using AI. A planning tool for couples who want to visualize before they commit.

Apr 19, 20265 min read
food-symptom-detectiveproducthealth

Finding Food Triggers: Science, Not Guesswork

Most food sensitivity tracking is just guessing. Food Symptom Detective uses a correlation engine with lag analysis and confounding variable control to find your real triggers — all with 100% local data that never leaves your phone.

Apr 19, 20265 min read
cortisengineeringon-device AI

How We Built an AI That Works Inside Siri

How Cortis runs a real language model on your iPhone and feeds answers back through Siri — no app opens, no internet needed. A technical look at headless on-device inference.

Apr 19, 20265 min read
subtrackerproductpersonal finance

The Hidden Cost of Subscriptions — And How to Take Control

The average person spends over $200/month on subscriptions and forgets half of them. Here's how SubTracker helps you see the full picture, set budgets, and stop paying for things you don't use.

Apr 19, 20264 min read
ai-habit-coachproductAI coaching

Why Most Habit Apps Fail — And How AI Coaching Changes That

Streak counters don't build habits. When the streak breaks, motivation dies. AI Habit Coach analyzes your patterns and gives personalized coaching — not generic advice, but specific guidance based on your data.

Apr 19, 20265 min read
pixiproductgaming

Why We Added RPG Progression to a Coloring Game

Coloring apps are relaxing but get boring fast. We added ranks, combos, achievements, and streaks to make pixel art coloring genuinely engaging long-term. Here's why — and how it works.

Apr 19, 20264 min read