Pitch Trainer is a free ear-training tool for practising two things: naming a note you hear and humming a note you are asked for. It runs in your phone's browser, needs no account, and can be added to your home screen.
A note plays at a random octave. Tap its name. Each note rotates through your chosen octave range, so the octave alone should not give the answer away. Notes you miss come up more often.
You are shown a note name. Hum or sing it in whatever octave suits your voice, without playing a reference first. The app listens through your microphone and counts it as correct when you hold the right note, within about a third of a semitone, for about three quarters of a second.
You start with three notes (F, C, G). Notes unlock around the circle of fifths, white keys first (F, C, G, D, A, E, B), then the black keys. A new note unlocks when your recent accuracy is high enough: 90% over 20 answers when naming, 80% over 10 when humming.
If you added an older shortcut, remove it first so you get the new icon.
Whether adults can truly acquire absolute (perfect) pitch is still debated, and no app can promise it. What regular practice reliably builds is better note recognition, a stronger sense of key, and better control when singing. Treat this as a practice tool, not a guarantee.