Sossego briefly listens to your room when you start, just to balance the sound for the space. The microphone stays off during the session. Nothing is recorded. Why?
Calm
Sound to settle the mind.
For best results, start 10–15 min before a stressful situation
Alternates sound between ears (EMDR-derived)
α relaxed focus · θ deep calm
No headphones detected — binaural beats need separate left/right channels.
Sleep
Ambient sound for falling asleep and overnight rest.
Gradually fades to silence near the end
Plug your phone in. Sleep mode keeps the screen on so audio continues through the night.
Reset
Breath to reset the nervous system.
For trains, offices, or sleeping partners — hum mentally
Keep sossego free
Sossego is free, ad-free, and account-free. If it helped you find a moment of stillness, a small contribution keeps it that way for everyone.
Support sossego →About Calm
sossego — Portuguese for deep, settled calm.
Binaural beats. Listening to two slightly different frequencies through headphones causes the brain to follow the difference between them — a phenomenon called frequency-following response. Meta-analyses report medium-to-large reductions in anxiety (Hedges' g ≈ 0.69 for theta-range protocols; standardised mean difference ≈ −1.38 in perioperative settings). The effect is strongest for situational anxiety; more modest for chronic conditions.
Isochronic tones. A single tone that pulses on and off at the target frequency, producing similar entrainment without requiring headphones — useful on speakers or single earbuds, though the aesthetic is more abrupt than binaural beats.
Music with embedded beats. A 2025 randomized controlled trial from Stanford's Center for Computer Research in Music and Acoustics (Venkatesan et al., n = 308) found that monaural beats embedded in harmonically-matched ambient music significantly reduced anxiety (d = −0.58), while beats alone or pure tones did not. Monaural beats work on any audio output, including phone speakers.
Bilateral motion. An optional layer that oscillates the audio slowly between ears, drawing on a technique from EMDR therapy. fMRI studies show bilateral alternating auditory stimulation modulates amygdala activity and facilitates fear extinction in healthy participants.
Sossego is a wellness tool, not a medical device. It is not a substitute for professional care.
References: Garcia-Argibay et al. 2019; Yan et al. 2025; Boukezzi et al. 2017.
Sossego subtly adapts the sound to your context — time of day, room brightness, and ambient noise level. The adaptation is silent and automatic; you don't choose it. Like a thoughtful instrument, the app responds to where and when you're using it. Learn more or disable.
About Reset
sossego — Portuguese for deep, settled calm.
Bhramari humming breath. Humming on a long exhale stimulates the vagus nerve directly through laryngeal vibration, while the extended exhale itself activates the parasympathetic nervous system. Studies of OM chanting and Bhramari pranayama show increases in heart rate variability — a marker of vagal tone and stress resilience. The pitch range used here (130–220 Hz) matches the range shown most effective for vagal activation.
Sossego is a wellness tool, not a medical device. It is not a substitute for professional care. Bhramari humming is not recommended during pregnancy, acute asthma, or active ear/sinus infection — consult a clinician first. Avoid practicing immediately after eating.
References: Inbaraj et al. 2022; Kumar et al. 2020.
Sossego subtly adapts the sound to your context — time of day, room brightness, and ambient noise level. The adaptation is silent and automatic; you don't choose it. Like a thoughtful instrument, the app responds to where and when you're using it. Learn more or disable.
About Sleep
sossego — Portuguese for deep, settled calm.
Ambient music for sleep. The strongest evidence in the sleep-audio category is for slow, low-tempo music. Bernardi et al. (2009) showed that musical tempo directly modulates heart rate and respiration, with slower tempos producing measurable cardiovascular slowdown. Meta-analyses of music-based interventions for sleep find modest but consistent improvements in subjective sleep quality and sleep onset latency in adult populations. The Ambient profile here uses sparse generative music in a low key, with no perceptible rhythmic pulse — designed around this evidence.
Pink noise. Pink noise — broadband sound with equal energy per octave, like distant rainfall — is widely used as a sleep aid. Its strongest documented benefit is masking: covering intermittent ambient sounds (traffic, snoring, household noise) that would otherwise interrupt sleep continuity. Evidence that pink noise itself improves sleep is more limited: a 2022 systematic review of 34 studies (Capezuti et al.) found some positive results but rated the overall evidence quality as low. The Pink noise profile here is offered for masking, not as a clinical sleep intervention.
Textures. This profile synthesizes soft tapping, brushing, and breath-like sounds in real time — the same procedural approach used everywhere else in Sossego, with no audio recordings. These sound types are associated with the ASMR (Autonomous Sensory Meridian Response) experience, which research (Poerio et al. 2018) has shown can lower heart rate and increase calm in people who experience it — roughly 20% of listeners by most estimates, with no effect or mild discomfort in others. Because this is synthesized rather than recorded, it's offered as a soft ambient texture, not a guaranteed ASMR trigger.
What this app does not do. The most rigorous research on acoustic sleep enhancement involves phase-locked pulses of pink noise timed precisely to the up-state of slow brain oscillations (Papalambros et al. 2017; Ngo et al. 2013). This requires real-time EEG monitoring via a headband — something a phone cannot do. Sossego's Sleep mode is ambient and supportive, not a treatment for insomnia or a substitute for clinical care.
Sossego is a wellness tool, not a medical device. It is not a substitute for professional care. If you experience persistent insomnia or sleep disturbances, consult a clinician.
Bernardi et al. 2009 (musical tempo and cardiovascular response); Capezuti et al. 2022 (systematic review of auditory stimulation for sleep); Papalambros et al. 2017 (phase-locked acoustic stimulation during slow-wave sleep); Poerio et al. 2018 (ASMR videos and physiological relaxation response).
Sossego subtly adapts the sound to your context — time of day, room brightness, and ambient noise level. The adaptation is silent and automatic; you don't choose it. Like a thoughtful instrument, the app responds to where and when you're using it. Learn more or disable.
Adaptive sound
Sossego shapes the audio character based on time of day, room brightness (via your phone's light sensor), and ambient noise level (measured briefly at session start). Morning sessions feel brighter; evening sessions feel warmer. Loud rooms get more pink-noise masking; quiet rooms let the music breathe.
Nothing is recorded. The microphone is opened only for an 8-second measurement when a session begins, then closed. No audio data is stored or transmitted. The light sensor reading is similarly transient — used once and forgotten.
For a fuller account of what runs locally on your device, see Technical details.
Technical details
Everything Sossego does, in plain terms.
Where the app runs
Sossego runs entirely in your browser. There are no user accounts, no servers storing your data, no analytics or tracking. The page loads from sossego.app, and from that point everything happens locally on your device.
Your session history
When you complete a session, Sossego stores a small record locally — the time, the mode, the duration, and (for Calm and Reset) the anxiety scores you give. This lives in your browser's localStorage. It never leaves your device. If you clear your browser data, the history is gone. You can also delete individual sessions from the History view.
The microphone
For users with adaptive sound enabled (the default), Sossego briefly opens the microphone at the start of each session — for about eight seconds — to measure the loudness of your room. This lets the app shape the audio to compete (or not) with the surrounding noise.
The microphone is then closed for the rest of the session. No audio is recorded, transmitted, or stored — only a single number (an average loudness in decibels) is computed and used locally. The browser shows its standard microphone indicator while this is happening.
You can disable this entirely using the microphone icon in the top bar, or by turning off adaptive sound in the About modal.
The light sensor
On phones that support it (most modern Android devices in Chrome), Sossego reads the ambient light sensor to shape the audio character — brighter in well-lit rooms, warmer in dim ones. This is a single brightness reading, used locally, never stored or transmitted. Devices without a light sensor (iPhones, most laptops) fall back gracefully to time-of-day estimates instead.
The screen wake lock
During active sessions, Sossego asks the browser to keep your screen on — otherwise audio playback would stop when the phone auto-locks. This uses the standard Screen Wake Lock API. When the session ends, the lock is released and the screen behaves normally again.
Audio
All sound in Sossego — binaural tones, isochronic pulses, the harmonium drone, generative ambient music, pink noise — is generated live by your browser using the Web Audio API. No audio files are downloaded. Nothing is streamed from a server. The math that produces the sound runs on your device.
Donations
If you choose to support Sossego, the donation goes through Stripe — a payment processor used by hundreds of thousands of businesses. Stripe handles your payment details directly; Sossego never sees them and doesn't store anything beyond the fact that a donation page was opened. There is no account linking, no email capture, no follow-up.
The code
Sossego is the work of one person and runs on a small budget. There's no team, no marketing, no investor pressure. It exists because anxiety is widespread and a thoughtful free tool feels worth making. If anything here matters to you, that probably matters too.
Safety information
Not recommended for individuals with epilepsy, photosensitive seizure disorders, or implanted medical devices (pacemakers, cochlear implants).
This is a wellness tool, not a medical device, and should not replace professional care. If you have concerns about anxiety or a mental health condition, please consult a qualified healthcare professional.
How anxious right now?
Session History
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Welcome to Bhramari
Bhramari is an ancient humming breath. The vibration in your throat and skull stimulates the vagus nerve directly — a way to calm the nervous system that listening alone cannot do.
Exhale & Hummmmm... at a pitch that feels comfortable — low to mid-range. Don't strain. Let the exhale be long.
Don't worry about getting it 'right.' Anything in the humming range works.