Sahha vs Junction

Both read wearables. Sahha also scores the phone in every pocket.

Junction, formerly Vital, runs the strongest lab-ordering network in digital health and reads wearables alongside it. Its scores need one worn overnight, against a 21-day baseline, so a phone-only user or anyone in their first three weeks produces no scored profile. Sahha scores that user from the phone alone, from day one. Both products are actively maintained, and they answer different questions.

Choose Sahha if

  • Your users include people who own no wearable
  • You need a mental wellbeing measure, not only physiology
  • You want behavioural segmentation without building it
  • You need a published price and a signed BAA

Choose Junction if

  • You need to order blood tests in the United States
  • You need BLE glucometers or blood pressure cuffs
  • EU data residency is a hard requirement
  • You want a SQL-like query layer over the raw data
Start free See the evidence
Coverage

The gate is not owning a wearable. It is wearing one to bed.

Both read Apple HealthKit and Health Connect through a mobile SDK, so both collect from a phone. What differs is the condition each one attaches before it will return a score.

Sahha

82–97%

Smartphone ownership across surveyed markets. Sleep, activity and mental wellbeing compute from phone signal alone, from the first day, with no baseline period to wait out.

Junction

13–46%

Wearable ownership across surveyed markets, which is the ceiling rather than the reach. Their documentation requires a daily long sleep session with overnight HRV and resting heart rate, against a 21-day rolling baseline, so users who charge the band overnight and everyone in their first three weeks fall below it.

Junction is explicit about this in their own docs, which is to their credit and makes it easy to check. The number that matters is not how many of your users own a wearable but how many wear one to sleep, nightly, and have done so for three weeks.

Junction readiness scores
Output

Both started at the same layer. They built in opposite directions.

Junction and Sahha were both wearable aggregators. Junction built upward into the clinic, adding a lab-ordering network and BLE medical devices that Sahha has no equivalent for, set out further down this page. Sahha built into behaviour. No archetype, tag or insight library appears in Junction documentation as of August 2026.

Junction docs
Junction
Normalized metrics 300+ wearables, plus BLE medical devices
Junction Sense Five scores, all needing overnight wear
Archetypes Not documented
Tags Not documented
Insights Not documented
Sahha
Granular data Raw sensor logs, included
Biomarkers 100+ across six categories
Scores Five, all working phone-only
Archetypes 14 archetypes, 100+ values
Tags Writable, 75+ symptom and reproductive terms
Insights Trends and comparisons
Price

One of these prices is on a website.

junction.com publishes no pricing and /pricing returns 404. The figures below come from the Vital-branded page their current documentation still links to for plan eligibility, so treat them as indicative rather than quoted.

What you can find out before a sales call Junction Sahha
Entry price $0.50/user, $300 minimum $399 flat
At 1,000 users $500 $399
Scoring Included Included
Gated above entry BYO OAuth, ETL, white-label, SLAs, Analytics API Nothing
Published on their own site No Yes
At 1,000 users $500, if that page holds $399

Monthly list on both sides; Sahha is $299 billed annually. The per-user model works in Junction’s favour below roughly 800 users, where their $300 minimum undercuts a flat $399, and against it above that. Their real number may differ from either, which is the point: you cannot budget without a sales call.

Vital-branded pricing page
Validation

Ask for the document.

Junction documents its method clearly: scores are personalised against a 21-day rolling baseline, and the stress score is derived from sleep duration with overnight heart rate and HRV. What the documentation does not carry is a study behind it, with a sample, a method or an ethics approval, so the scores can be understood but not independently checked.

The same is true one layer down. SOC 2 Type 2, ISO 27001, GDPR and HIPAA appear as badges on their homepage, and no security or trust page sits behind them; those URLs return 404. That is a gap in what is published rather than evidence of anything, and the fix is simply to ask them for the report before signing.

Sahha publishes the study underneath its models with sample size, ethics approval and limitations stated, and runs the same models on every deployment, so a score means the same thing in your product as in anyone else.

2,068
participants
26,888
PHQ-9 responses
21/074
Otago ethics approval
Read the research Junction readiness scores
Limitations

What Sahha does not do.

No lab ordering
Junction runs a nationwide US lab network with four collection modalities, requisitions, phlebotomy dispatch and critical-result handling, through CLIA and CAP certified partner labs. Nothing else in this category has it, and no amount of wearable data substitutes for a blood panel. If your product orders tests, that is the whole decision.
No BLE medical devices
Sahha collects through the OS health stores and direct cloud connections. Junction pairs directly with blood pressure monitors, glucometers and CGMs including Omron, Accu-Chek and FreeStyle Libre. For a remote monitoring product built on cuffs and meters, that is their category.
No EU data residency
Junction pins a team to the United States under HIPAA or Belgium under GDPR, with separate sandbox and production environments per region. Sahha is US-incorporated and offers no customer-selectable region. Where residency is a hard procurement requirement, this decides it outright.
No query language over the data
Sahha delivers over webhooks and REST, and you model on top of what arrives. Junction Sense adds a SQL-like DSL with a Python SDK, DataFrame integration and continuous queries that fire a webhook on change. For a data science team that wants to ask questions in place, that is a better interface than ours.
Switching

Moving from Junction to Sahha

Most of a move in this category is mechanical. One part is not, and it is worth knowing which before you commit either way.

  1. Junction live
    Sahha live
    new signups → Sahha
    No cutover date

    Run both at once on the free trial

    Build against Sahha’s sandbox on the 30-day free trial with your Junction integration untouched. If you need lab ordering, running both permanently is a legitimate end state rather than a failure to choose.

  2. Sleep · last 30 days backfilled
    30d ago today
    Do this first

    Export while their backfill window is open

    Junction’s backfill is one of the better ones in the category, up to 365 days configurable on some providers. That is history you can recover today and cannot recover once an account closes. Pull it before you decide anything.

    Junction backfill docs
  3. A

    Allow “your app”

    Sleep
    Activity
    Connect
    Once at most

    Re-consent depends on who owns the connection

    When a user connects a wearable, that permission belongs to whoever registered the connection. Sahha uses accounts you create and own, so connections you already hold move across and your users do nothing. Where your current vendor owns them, users approve once more, into an account that is then yours. Phone data is unaffected either way: Apple Health and Health Connect grant it to your app, not to the code inside it.

  4. # one webhook consumer POST /sahha/webhook { "profileId": …, "scores": […] }
    Plan for it

    Scores will not match, and should not be expected to

    Junction Sense personalises against a 21-day rolling baseline, so its values are relative to each user’s own recent history rather than to a fixed scale. Expect a visible discontinuity in any trend chart, or re-baseline at the switch.

    Junction readiness scores
If diagnostics is why you chose Junction, none of this applies and you should stay. The two products overlap on wearable ingestion and almost nowhere else.
Evidence

Line by line.

The checks that rarely decide a comparison but always come up before signing.

Criterion Sahha Junction
Is the wearables product still being developed? Wearable and phone signal is the whole product, not a second line. Yes. Samsung Health was added in March 2026 and the changelog carries entries through July 2026. The company now leads with lab diagnostics, which is a change in emphasis rather than in what is supported. Junction Series A announcement
Can I write straight into my own datastore? No. Delivery is webhooks and REST, and you land the data yourself. Yes, on higher tiers. Managed ETL to Azure Event Hubs, Google Cloud Pub/Sub and RabbitMQ, alongside REST and roughly 110 webhook event types. Junction API docs
Can I get FHIR-formatted output? No. Sahha returns its own schema over webhooks and REST. Not any more. FHIR is not mentioned anywhere in current documentation, though Vital advertised HL7 FHIR output on its homepage as recently as February 2025. Junction docs
Is there a mental wellbeing measure? Yes. Mental wellbeing is one of the five scores, with full factor coverage from phone signal, backed by published research. No mental health, mood or wellbeing construct exists in their documentation. Their stress score is physiological, derived from sleep duration and overnight heart rate and HRV. Junction readiness scores
How much history arrives at signup? 30 days, included on every plan and on by default. Provider-dependent and generous: 30 days for HealthKit and Health Connect, 90 for Fitbit and Garmin, 180 for Oura and WHOOP, up to 365 configurable. Health Connect is not configurable. Junction backfill docs
How do I get a signed BAA? From the Pro tier, at a published $1,499/month. No sales call. No mention of business associate agreements appears anywhere in their public documentation. That is an absence of a statement rather than a refusal, so ask them directly. Junction docs

Every Junction claim links to their own documentation. Verified 2026-07-26.

FAQ

Sahha vs Junction, answered

Has Junction stopped supporting wearables?

No, and it is worth saying plainly because the rebrand invites the assumption. Samsung Health was added in March 2026, the changelog carries entries through July 2026, and all five mobile SDK repositories have been updated recently. What changed is prominence: Junction leads with diagnostics on its homepage and has no product-level navigation item for device connectivity. That is a positioning decision, not a deprecation.

Why does Junction say 300+ devices when it used to say 500+?

Both figures are live on their own properties. The homepage and documentation state 300+ wearables. The March 2025 Series A announcement still states 500+ wearables and medical devices. Junction has published no explanation for the difference and we are not going to invent one. If device count decides your purchase, ask them for the current list rather than relying on either number.

Is Junction cheaper than Sahha?

Probably not at 1,000 users, though their published position makes it hard to be certain. No pricing appears on junction.com and /pricing returns 404. The Vital-branded page their documentation still links to for plan eligibility lists $0.50 per user per month with a $300 monthly minimum, which works out to $500 at 1,000 users against Sahha’s published $299. That page also carries compliance badges that are stale relative to junction.com, so treat it as indicative rather than authoritative and get a quote before deciding on price.

Does Junction support FHIR?

Not according to current documentation, where FHIR is not mentioned. This is worth flagging precisely because it changed: Vital advertised HL7 FHIR output on its homepage in February 2025. We do not know why it is absent now and will not speculate. If FHIR is a requirement, ask them directly rather than relying on either the old page or its absence from the new one.

Can Sahha replace Junction?

Only if you were using it for wearable data and scoring. Sahha has no lab ordering, no clinical biomarker panels and no BLE medical device connectivity, and none of its output substitutes for a blood panel. What it adds is a mental wellbeing measure, behavioural archetypes, and scores that keep working for users who own no wearable. Several teams would reasonably run both.

Keep comparing

Same research standard, same sourcing. See all comparisons .

All Junction information on this page reflects publicly available documentation as of July 2026, linked at the point of each claim. Product details change. If something here is out of date or inaccurate, email support@sahha.ai and we will correct it. Trademarks are the property of their respective owners. Sahha is not affiliated with, endorsed by, or sponsored by Junction.

Run both on your own users.

Thirty days, every product unlocked, no cutover. The number that settles this is what comes back for your users, including the ones who own no wearable.

Start free Read the research

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