Every IOHID temperature sensor your machine exposes, rendered as a glowing thermal control room. Each fan widget binds to a real on-die sensor — blade speed and color track the measured temperature. Version 3.0 adds desktop widgets, 30 days of thermal history with trend deltas, battery health and live power draw, and thirteen themes that can follow macOS light and dark mode. No telemetry. No network. Just live heat.
Heatsink reads every chip-level thermal signal macOS exposes, renders them with cinematic clarity, and stays out of your way the rest of the time.
Small, Medium, and Large widgets for the desktop and Notification Center. Hottest sensor on an arc dial, average, sensor count, last-hour sparkline with peak, fan glyphs — the same numbers the dashboard shows, refreshed within seconds, with the exact time of the reading stamped on the widget.
The live chart now goes long: 24-hour, 7-day, and 30-day views recorded to disk, scrollable back through 90 days of hourly summaries. Trend badges show how today compares with yesterday and how this week compares with last. Gaps are labelled honestly as "not recording", never drawn as zero.
Charge, full-charge capacity versus design capacity, cycle count, chip-versus-battery temperature chart, and a long-term health decay curve logged once a day. Portable computers only — desktop models simply don't show the tab.
Live system power draw with a power-versus-CPU-load chart. On battery it shows the real discharge rate; on mains it switches to wall-power mode with the adapter's rating.
Ten dark themes plus three new light ones — Polaris, Paper, Carbon. Turn on "Follow system appearance" and Heatsink swaps between your chosen dark and light themes whenever macOS does. Each theme has its own animated background, all GPU-drawn, under 2% CPU.
A dashboard card that shows how many degrees remain before your configured critical threshold — the number that actually tells you whether a long render or compile is about to throttle.
Reads every temperature sensor your machine exposes — typically 15+ on-die readings on Apple Silicon. Refreshes once per second. Calibration references are excluded so "hottest" is always a real die sensor.
Each fan widget binds to a real die sensor — blade speed, glow color, and HOT/WARM/COOL badge driven by the zone's measured temperature. Fanless models get a chip-die view instead.
Every time macOS throttles your chip, Heatsink records the start time, duration, peak temperature, and severity. Persistent across launches so you can look back at when the machine was really under pressure.
Animated fan icon plus the live reading in your menu bar, with a popover showing the last five minutes. Pin any specific sensor (CPU die, GPU die, battery — whatever you care about) and the menu-bar number tracks that one instead of "hottest."
Set independent warning and critical temperature thresholds with their own cooldowns. Local notifications only — no servers, no accounts, no opt-in trackers.
Save the rolling-hour buffer as a colour-coded HTML report (severity legend, plain-English column glossary, opens in any browser) or as machine-readable JSON (stable schema, canonical Celsius, ISO-8601 timestamps) for piping into scripts.
The built-in Help spells out which numbers are measured, which are derived, and which are estimated. Fan speed is labelled EST because Apple Silicon does not expose fan RPM to sandboxed apps — Heatsink never invents a figure.
No analytics. No telemetry. No network calls of any kind. Sensor data never leaves your machine. Sandboxed; privacy manifest bundled.
Three widget sizes on the desktop and in Notification Center, plus battery, power, and long-range history tabs on the dashboard. Every capture below is real — taken on a MacBook Pro running 3.0.
Small · Medium · Large — live on the desktop, same readings as the dashboard, stamped with the time of the reading
HISTORY · 7 DAY — scrollable, with "VS PREV 24H" and "VS PREV WK" trend badges and honest NOT RECORDING gaps
BATTERY — charge, health with real mAh figures, cycles, chip vs battery temperature, long-term decay
POWER — live wattage and efficiency, with a power × CPU-load chart over 5, 15, or 60 minutes
Menu bar — animated fan icon, live reading, and a popover with the last five minutes at a glance
Whether your chassis has 0, 1, 2, or 4 fans, the dashboard reshapes itself to match the hardware. Fanless laptops get a silicon-die view; the Mac Pro tower gets all four.
MacBook Pro 14"/16" (M-Pro/Max) · two fans bound to the hottest on-die zones
MacBook Neo (2026) · A18 Pro · 6-core CPU · iPhone-class silicon, fanless
MacBook Air (M5) · fanless · chip diagram with live core sensors
Mac mini · single-fan layout, base M-series chip
Mac Pro (M2 Ultra) · four fans — three front impellers and the rear blower, each bound to its own thermal zone
Every theme is a complete colour palette and its own bespoke animated background — rising embers, hex control grid, plasma sheets, falling digital rain, cherry petals, aurora ribbons, particle network, CRT scanlines, drifting snow. Three light themes join the ten dark ones in 3.0, and "Follow system appearance" switches between your chosen pair whenever macOS changes mode. All GPU-rendered, under 2% CPU.
Furnace · Deep navy plate with a glowing red fan core. CRT scanlines.
Phosphor · Black chassis with amber phosphor — classic CRT terminal.
Voltage · Pure black + neon cyan accents. Maximum contrast.
Inferno · Molten forge — cast-iron plate, sunshine blade, rising sparks.
Reactor · Control room — gunmetal plate, Cherenkov teal hex grid.
Plasma · OLED cyberpunk — pure black with rolling plasma sheets.
Cascade · Hacker terminal — pure black with falling green glyphs.
Sakura · Cherry blossom — dusk rose plate with drifting petals.
Aurora · Northern lights — midnight blue plate with emerald ribbons.
Quantum · Particle physics — indigo void with linked drifting particles.
Polaris · Arctic glacier — frost-white plate with drifting snow. Light.
Paper · Warm cream — paper chassis, ink black, faint grain. Light.
Carbon · Brushed metal — gunmetal weave with tungsten orange.
Heatsink does exactly one thing: read sensors locally and render them. There is no other thing.
A one-time purchase — no subscription, no account, no tracking. Runs on macOS 13 or later, Apple Silicon and Intel. Widgets need macOS 14 or later.
$6.99 · One-time purchase. Every update is free.
Heatsink