Dev Log

We loved Captio so much, we wanted to recreate that experience.
This dev log documents the technical decisions behind building Simple Memo - for Obsidian.

What comes next is laid out in what we build next — including the survey that decides the order.

February 13, 2026

[Day 1] Loved Captio So Much, I Had to Recreate That Experience

Send with one tap and keep unsent notes for retry. Dissecting the Captio experience and documenting every technical decision: UIKit, Outbox architecture, Relay API, and privacy-first design.

UIKit Outbox Cloudflare Workers Privacy Swift

Technical Deep Dives

UIKit vs SwiftUI: Choosing for Launch Speed

Why UIKit in 2026. Architecture designed around a Time-to-Text target under 500ms.

Outbox Architecture: Designing Against Message Loss

Instant UI clear on send, with unsent messages kept and retried. The full AES-GCM encrypted Outbox pattern.

Relay API: Email Infrastructure on Cloudflare Workers

Sending without mailbox OAuth: a relay API on the edge (Cloudflare Workers) that sends through Resend.

Privacy-First Design: Obsessive Attention to Detail

On-device encryption, session storage, logs, and analytics, including the current limits of app-switcher privacy.