Oura Just Filed Confidentially for an IPO at $11 Billion. 5.5 Million Rings Are Already Tracking Your Next Customer's Sleep. Here's the Developer Opportunity Before the Marketing Machine Turns On.
On May 21, Oura confidentially filed its IPO prospectus with the SEC. The company is valued at $11 billion following a $900 million Series E in October 2025. They've sold 5.5 million rings as of Q3 2025 and are forecasting $2 billion in annual revenue for 2026, 4x growth from $500 million two years ago. Goldman Sachs, Morgan Stanley, and JPMorgan are on the deal. The listing is expected later this year.
Oura has had a developer API since roughly 2019. It's open. And the indie developer community building on top of it is still small enough that the competition for attention isn't fierce yet.
That changes when Oura goes public.
What the ring actually captures
This matters because most health apps are working with shallow data. The Oura ring captures continuous heart rate, heart rate variability (HRV), skin temperature deviation from baseline, blood oxygen saturation (SpO2), sleep staging (light, deep, REM, awake), and activity metrics. Not step counts: longitudinal physiological data collected every night, building a baseline over months.
HRV in particular is the metric that the quantified-self community has been chasing for years, and Oura's ring-based measurement during sleep is meaningfully more accurate than wrist-based optical sensors. The device has been used in research studies (including COVID-19 early detection research at UCSF) specifically because the data quality is different from what Apple Watch provides.
At 5.5 million users, that's 5.5 million people generating continuous health data, most of them in the $75,000+ household income bracket who paid $300 for the ring. The customer profile is specific: health-motivated, high-income, already comfortable with data sharing and wearable technology.
Why going public changes the developer calculus
Before an IPO, developer platforms are volatile. The company can pivot, deprecate the API, change pricing, or shut down the program without being accountable to public market expectations. Post-IPO, that changes, not because public companies are always great developer partners, but because an $11B company with Goldman and Morgan Stanley underwriting has made implicit commitments about the stability and growth of the platform.
Fitbit had an open developer API, then Google acquired it and started restricting access. Garmin has a developer program that's been stable for years. Apple HealthKit has been consistent. Oura post-IPO is more likely to look like Garmin (a platform that takes developer partners seriously because they contribute to the ecosystem story) than the pre-acquisition Fitbit model.
The window I'm describing is the 3-6 months between now and the IPO roadshow. Right now, Oura's developer documentation is solid but not heavily promoted. The developer community is small. App reviews on the Oura app store are light. If you ship something in this window, you get early discovery before the post-IPO marketing push brings in a wave of new builders.
What you can actually build
The Oura API gives you access (with user OAuth consent) to: daily and weekly readiness scores, sleep data including stages and duration, HRV, heart rate throughout the day, activity data including step equivalents and active calories, and body temperature deviations.
The use cases that map well to the Oura dataset:
Personalized recovery optimization for athletes. Oura's own readiness score is generic. A tool that correlates HRV patterns with training load data from Strava or Garmin and gives sport-specific recovery guidance is more valuable than Oura's default. Small niche, but the users who care about this will pay for it.
Sleep quality B2B integrations for corporate wellness programs. A growing number of enterprise wellness platforms want continuous health monitoring data. Oura + corporate wellness = a productized integration play. The compliance overhead is real (health data + employer = tricky), but companies like Whoop have done this successfully.
Stress and burnout early warning for knowledge workers. HRV is the best non-invasive proxy for nervous system load. A tool that monitors HRV trends over weeks and surfaces "you've been in a stress pattern for 12 days, here's what happened last time this occurred" is genuinely useful and doesn't require medical device certification because it's wellness, not treatment.
AI health coaching on top of longitudinal data. This is where the AI angle is strongest: LLMs are mediocre at generic health advice and excellent at pattern synthesis across long data histories. "Based on your Oura data from the last 90 days, the three nights before your worst HRV readings all had alcohol within 4 hours of sleep and late screen exposure" is a real insight that a system with access to the data and an LLM for synthesis can produce.
The actual limits
5.5 million users globally is meaningful but not massive. Building a product on Oura's API means building for the population that paid $300 for a ring: affluent health enthusiasts in the US, Europe, and increasingly Japan. That's a specific addressable market, not a general consumer market.
Apple Watch is the 800-pound gorilla in the room. Apple has been expanding its health sensor suite every year. If Apple ships a ring form factor or a sleep-focused mode that captures ring-quality HRV data, the competitive moat around Oura's device narrows. The data quality advantage is real today; it may be less real in two years.
The other real constraint is user motivation. Oura's best customers are already using the ring and already somewhat engaged with the data. Building a product that requires a new behavior (open this app, interpret this chart, adjust this habit) on top of an existing habit (wearing the ring) has classic behavior change friction. Products that integrate passively (that just work in the background and surface an insight when it matters) tend to work better on this platform than ones requiring active engagement.
The window is real
Oura going public is a forcing function, not just for Oura but for developers on the platform. Post-IPO, the developer competition intensifies, the "early partner" advantage disappears, and the free discovery that comes from being one of a small number of apps in the Oura ecosystem gets more crowded.
If you build health or wellness products and haven't looked at the Oura API, look now. Not because every solo operator should pivot to health tech (most shouldn't) but because $11B of public market validation and 5.5 million high-income engaged users is a real foundation that will be more competitive in 12 months than it is today.
The pre-IPO developer ecosystem window is a recurring pattern. It happened with Stripe before the 2012 launch, with Shopify's developer platform before 2016, with Twilio before its 2016 IPO. The pattern is consistent: the developers who shipped real products in the window before the platform became crowded got outsized distribution. You don't have to believe Oura is those companies. You just have to think the calculus is worth a week.
Author
Lukas
@lukcombinator