Does Diffuse sync my Mac history to my iPhone?

No. Each device is a closed history. If you need a copy off the device, you export it yourself — Files, AirDrop, or the diffuse-dev CLI — with a redaction policy.

Where are snapshots stored?

On the device that captured them, as readable JSON. Apple uses Application Support / Diffuse. Android uses the app-private files directory and excludes it from backup. There is no Diffuse account and no Diffuse cloud.

Yes. Diffuse is open source under the MIT License. GitHub hosts the source and unsigned CI artifacts. You sign local shipping builds yourself.

How often does Diffuse capture?

Default cadence is every four hours with a 15-minute floor, including wake. Automatic captures can skip persist when nothing changed. Manual capture always saves.

Do tests require Node or Docker?

No. Collectors use process-runner doubles. CI never requires a particular Wi-Fi network, Node, or a Docker daemon. Android JVM tests read the shared Fixtures/ directory.

Diffuse — See what changed on this device

Q: What does Diffuse never collect?

Passwords, tokens, Keychain, SSH or GPG keys, environment variable values, file contents, messages, mail, photos, browsing history, location coordinates, and anything sent off the device.

Q: Is Android a wrapper around the Apple apps?

No. Diffuse for Android is native Kotlin and Jetpack Compose with its own domain engine. The two families interoperate through schema-v1 JSON snapshots and golden fixtures, not a shared UI runtime.

Q: Does the Android app need Internet?

No. It observes ACCESS_NETWORK_STATE so connectivity can be recorded. There is no INTERNET permission, no account, and snapshots are excluded from Android backup.

The question

Two points in time. One honest diff.

Diffuse is not a dashboard of everything. It is a record of what moved — Node upgraded, a volume vanished, Wi-Fi flipped from Home to Office, a watched repo changed branch.

Diffuse for Mac: overview showing 12 changes, a Studio Display removed, network Home to Office, and a Git branch switch. — macOS · Overview

Diffuse on iPhone: four changes since the previous snapshot, Wi-Fi to Cellular. — iPhone

Diffuse on iPhone compare screen with before and after values. — Compare

Diffuse on Apple Watch showing Δ 4 changes at a glance.

Δ on your wrist

Standalone watch app and complications. No paired iPhone required. The widget never decodes a snapshot — just a count and a peak severity.

Five apps

Written for the device, not scaled down.

Same question everywhere. Adaptive Compose on Android. Split view on Mac. Tabs on iPhone. Three columns on iPad, including portrait. A glance on Watch.

macOS

The full workspace

Navigation split view, menu bar extra, scheduled capture on a timer and on wake, repository watch list, developer-tool collectors. Not sandboxed — because spawning node --version should not hide behind a temporary exception.

Mac compare workspace with a timeline of snapshots and a detailed diff.

iPadOS

Three columns, always

Snapshots, changes, and clusters side by side. Regular width never collapses to a phone layout.

iPad three-column workspace: snapshots, changes, and clusters.

iOS

Phone, not a shrunk Mac

Overview, timeline, compare, settings. Capture on open, on demand, and via background refresh.

Android

Kotlin, all the way down

Native Compose UI, adaptive navigation, local JSON history, privacy-led export, and WorkManager scheduling. No Swift bridge and no Internet permission.

Diffuse for Android overview showing changes since the previous snapshot.

What it observes

Honest per platform. Not a pretend Mac on a Watch.

A capability is a stable id, a travelling schema, and a collector. Register it only where the hardware can actually see it. Adding Bun is a tool adapter. Adding Bluetooth peripherals would be a new capability.

Mac capabilities list: system, hardware, displays, network, storage, developer tools, and git watch list. — macOS · Capabilities

Diffuse for Android settings: capture cadence, skip-unchanged, and capability toggles. No Internet permission. — Android · Settings

Mac

System OS, model
Hardware chip, memory
Displays resolution, refresh
Power battery, adapter
Network path, interfaces, SSID
Storage all volumes
Apps bundle id
Tools node, git, docker…
Git watched repos
Processes opt-in

iPhone & iPad

Device model, name
System version
Battery charge, state
Screen size, scale
Network path, interfaces
Storage app container
No process list
No git spawn
No developer-tool probes

Watch

Device model, size
Battery charge
System version
Storage container
Network path
Standalone — no iPhone required
Glance + Δ complications

Android

Device model, API, architecture
System kernel, locale, memory
Battery level, health, temperature
Display resolution, density, refresh
Storage app data volume
Network connectivity, VPN, interfaces
No accounts or hardware IDs
No installed-app or process inventory
No Internet permission

nodepythonswiftrustcgo rubyjavadenobunnpm pnpmyarnbrewdockerterraform gitxcodebuildcargouv

How it works

Capabilities travel with their own schema.

Adding something new to observe is a typed model, a collector, a registry line, and a test. Not a new screen. Not a new diff algorithm.

01 · Capture

Snapshot

Collectors run concurrently with a deadline. One failure never fails the snapshot. Manual captures always persist. Automatic ones can skip if nothing moved.

02 · Compare

Schema-driven diff

Identity matching, semantic versions, relative free-space noise, severity, clustering. diff(A, A) is empty. Change ids are content-derived — no random UUIDs.

03 · Keep

Files you can read

Application Support. One JSON file per snapshot plus a rebuildable index. Retention never deletes the newest. Export redacts by classification.

Schedule

Every four hours

Default cadence, with a 15-minute floor so a laptop that sleeps repeatedly does not flood the timeline.

Wake

System events

Mac captures on unlock. iPhone and iPad use background refresh. Watch uses its own refresh task. Android uses WorkManager. Same decide function.

Quiet

Skip if unchanged

Automatic captures may skip persist when the latest snapshot diffs empty. Pressing capture always saves.

Keep

90 days · 1 GiB

Retention never deletes the newest snapshot. Pinned and labelled ones are protected. Preview before prune.

A workday

The story the fixtures tell.

Same Mac, morning to evening. Diffuse does not infer why — it reports what moved, with severity, and groups changes a few minutes apart.

09:04 Scheduled snapshot. Quiet morning: volumes, Wi-Fi Home, tools as yesterday.
11:42 Node upgraded. Homebrew prefix unchanged. Significant, not a new capability.
17:18 Network Home → Office, VPN off → on. SSID is sensitive on export.
18:03 Watched repo switched branch. Git stores host + dirty + ahead/behind — not the diff.
19:11 Studio Display gone. Identity is the display, not the name on the bezel.

Scope

Deliberate non-goals.

These are product decisions, recorded as ADRs — not missing features.

Diffuse does

Capture and diff on the device that observed it
Redact by classification when you export
Ship five native apps and a UI-free CLI
Keep snapshots as readable JSON you can copy

Diffuse will not

Sync Mac history to iPhone — or Android to anything else
Open an account or a cloud
Put a signing identity in this repository
Infer “why” with a model in the diff path

Privacy

Useful on device. Quiet on export.

An SSID is how you see Home → Office. It is also how a gist becomes a map of your life. Collection stores the real value. Sharing applies a policy.

Restricted fields never leave — even on “full detail.” Process listing is off until you turn it on. Git records branch, dirty, ahead/behind, and a remote host. Not file names. Not diffs.

Public OS version, model identifier Always included
Local Device name Standard export
Sensitive SSID, repository path Redacted unless full detail
Restricted Never designed to leave Always stripped

Never collected Passwords · tokens · Keychain · SSH/GPG keys · .env values · file contents · messages, mail, photos, browsing · location coordinates · anything sent off-device.

diffuse-dev

The same engine. No UI framework.

Capture, inspect, diff, validate, and print the generated privacy ledger from a terminal. Proof that the product is a domain, not a SwiftUI screen.

diffuse-dev

# What can this Mac observe right now?
swift run diffuse-dev capabilities

# Capture, then compare
swift run diffuse-dev snapshot /tmp/before.json --repos "$HOME/code/Diffuse"
swift run diffuse-dev snapshot /tmp/after.json --label "after lunch"
swift run diffuse-dev diff /tmp/before.json /tmp/after.json --markdown

# Fail a job if the build environment drifted
swift run diffuse-dev diff "$BEFORE" "$AFTER" --fail-on-change

capabilities

What this machine can observe right now, and why a collector is unavailable.

inspect · validate

Summarise a file. Fail if the snapshot does not match the current schema.

privacy

Print the generated ledger — the same contract the in-app Privacy screen uses.

--fail-on-change

Exit 2 when significant changes exist. A CI gate for environment drift.

Inside the apps

From the running product. Not mockups.

macOS · Snapshots Mac snapshots inspector with the latest capture selected.

macOS · Privacy Mac privacy ledger generated from live capability metadata.

Android · Compare Android compare screen with battery and system changes and a share-redacted-report action.

Android · Privacy Android privacy ledger: on-device storage, never-collected list, and classification.

iPhone · Privacy iPhone privacy screen: everything stays on this device, never collected.

iPad · Privacy iPad privacy sheet over the three-column workspace.

Start

Clone. Capture. Compare.

macOS, Xcode 16+ / Swift 6, XcodeGen, SwiftFormat for Apple. JDK 17+ and Android SDK 36 for the Kotlin app. A healthy Apple checkout prints Diffuse is healthy.

01

Bootstrap

Generates the Xcode project from project.yml. The .xcodeproj is gitignored on purpose.

./Scripts/bootstrap.sh

02

Verify

Format lint, tests, iOS/watchOS cross-check, unsigned Apple builds, plus a separate Android test, lint, coverage, and build pipeline.

./Scripts/verify.sh

03

Snapshot

Same engine as the Apple apps. Writes a file you name — it does not open Application Support.

swift run diffuse-dev snapshot

04

Android

Independent Kotlin engine. Fixture tests decode the same golden snapshots the Swift suite pins.

cd Android && ./gradlew testDebugUnitTest

FAQ

Straight answers

Does Diffuse sync my Mac to my iPhone?

No. Each device is a closed history. Export if you need a copy — Files, AirDrop, or diffuse-dev — with a redaction policy.

Where do snapshots live?

Application Support / Diffuse/ on that device. Pretty-printed JSON plus a rebuildable index. You can open one in a text editor.

Why isn’t the Mac app sandboxed?

Developer-tool collectors spawn git and node --version. The App Sandbox forbids that without a temporary exception per binary. Documented, not papered over.

Is there telemetry?

No account, no cloud, no crash reporter that uploads snapshots. GitHub is for source and CI artifacts only.

How much does it cost?

Nothing. MIT licensed. Unsigned CI builds; you sign whatever you ship.

How often does it capture?

Default cadence is every four hours, with a 15-minute floor on every trigger including wake. Skip-if-unchanged applies to automatic captures only.

Why are widgets empty in a CI build?

Unsigned builds have no app-group container. The extension still compiles and shows empty rather than crashing.

Do tests need Node or Docker installed?

No. Collectors take a fake process runner. Live capture tests stay on cheap, stable Mac collectors. Android JVM tests read Fixtures/ directly.

Is Android a wrapper around the Apple apps?

No. It is native Kotlin and Jetpack Compose with its own domain engine. Compatibility is schema-v1 JSON and golden fixtures — not a shared runtime, JNI bridge, or Flutter shell.

Does the Android app need Internet?

No. It reads ACCESS_NETWORK_STATE so connectivity can be observed. There is no INTERNET permission, no account, and no backup of snapshots.

Where do Android snapshots live?

The app-private files directory as pretty-printed JSON. They are excluded from Android backup and device transfer. Export is a user-picked share with the same classification rules as Apple.

See what changed.

Two points in time. One honest diff.

Δ on your wrist

Written for the device, not scaled down.

The full workspace

Three columns, always

Phone, not a shrunk Mac

Kotlin, all the way down

Honest per platform. Not a pretend Mac on a Watch.

Mac

iPhone & iPad

Watch

Android

Capabilities travel with their own schema.

Snapshot

Schema-driven diff

Files you can read

Every four hours

System events

Skip if unchanged

90 days · 1 GiB

The story the fixtures tell.

Deliberate non-goals.

Diffuse does

Diffuse will not

Useful on device. Quiet on export.

The same engine. No UI framework.

From the running product. Not mockups.

Clone. Capture. Compare.

Bootstrap

Verify

Snapshot

Android

Straight answers

Your machine, observed by you.