ResearchKit is an open-source framework for building iOS research apps. It gives developers building blocks; it is not a study system. If you want questionnaires, consent and a data back end without app development, Capture is a different route.
Free sandbox · No credit card · 21 CFR Part 11 aligned
Tests
5
Hands-on
4
To confirm
1
Capture vs ResearchKit: the short version
0
sales calls needed to start building
1
audit trail across EDC, ePRO, eConsent and randomization
Free
sandbox with every feature, no time limit
EU + US
hosting in Frankfurt or N. Virginia
The wedge
ResearchKit solved a real problem for academic and digital health teams: how to build a good-looking iPhone app that can run surveys, collect consent and run structured tasks without starting from nothing. The code is open source under a BSD-style licence, and teams with developers have used it to build their own apps. For a research group whose study is the app, such as a novel sensor-based task, a framework is the right level of control.
Most clinical studies are not trying to ship an app. They need a participant to answer a questionnaire on schedule, sign a consent, and have those results arrive in a database where a coordinator can see compliance, a monitor can raise a query and an auditor can read the audit trail. None of that comes with a UI framework. You need a back end that receives the data, authentication, storage, a record of every change, an administrator view, hosting that fits your data protection rules and a process for validating and updating the app after every iOS release. That is a software project with its own maintenance, usually bigger than the study team expects.
Capture answers the same participant-facing need without that project. Participants open a secure link on their own phone with no app store, questionnaires follow the visit schedule with reminders, consent is signed on screen with a verified process, and every answer lands in the same study as the EDC data and randomization. If your study needs a custom sensor or task that only an app can deliver, a custom app may still be right; in that case consider keeping the clinical record in a study system. See ePRO software for clinical trials for what a no-code route looks like.
Who will maintain the app after the first release, and for how long? Who owns the back end and its validation? What happens to participants who do not have an iPhone? How will you pass the app store review, and how will you ship urgent fixes mid-study? If the answers are uncertain, a configurable platform may carry less delivery risk. Read BYOD ePRO without an app download for the device side of that decision.
What to compare
| Criterion | Why it matters | Capture |
|---|---|---|
| Build effort | Time to a first participant | No code: build forms in the visual builder or have AI draft them from a protocol; test free in the sandbox |
| Participant access | Who can take part | Opens in the phone browser from a secure link; no app install, no app store |
| Audit trail | Who changed what, when and why | Field-level, append-only, with user, time, old and new value and reason; exportable |
| Back end | Where the data goes and who controls it | Included: EU (Frankfurt) or USA (N. Virginia) hosting, role-based access, row-level security |
| Signatures | Consent and investigator sign-off | Verified eConsent; re-authenticated investigator signatures with a meaning statement |
| Data checks | Clean data at entry | Range and custom-value edit checks raise auto-queries when a site enters a value that breaks a rule |
| Site and study management | Coordinators and monitors need a view | Site coordinator portal, queries, SDV per field, monitoring dashboard, randomization in one study |
| Validation and maintenance | Keeping a regulated system fit for use | Draft to approved form lifecycle; no per-OS app updates to manage |
| Data export | Analysis-ready datasets and a data dictionary | CSV or Excel with an automatic codebook; SDTM as SAS XPT with Define-XML |
| Commercial model | Budget for a small study | Free sandbox with every feature; no setup fee; pay only when you go live |
This table shows Capture's answers only. Ask ResearchKit for theirs, and confirm current capabilities and terms directly with them.
Compliance controls
Every change is written to an append-only, hash-chained audit trail with user, time, old and new value and reason. Electronic signatures require password re-authentication and carry a meaning statement. Roles separate sites, and identifying data is segregated from study data at the database layer.
Weight changed 68.0 to 68.5 kg
Site coordinator · Reason: Transcription error
Query Q-0014 answered on Weight
Site coordinator · Reason: Source checked
Vital signs form locked
Data manager · Reason: Visit cleaned
Longitudinal studies
Each visit is anchored to screening, a milestone, an earlier visit, a fixed study day or a date recorded on a form, with a window and an enforcement mode. Questionnaires follow the schedule, reminders go out by email or SMS, and the status overview shows every participant against every visit.
Window -3 / +3 days around the anchored target date
Soft window
Stays available with a protocol deviation flag
Hard window
Locks outside the window
Warning only
Stays available with a warning
Auto-close
Marked missed when the window closes
Describe it or upload it, and let the AI draft the questions in the free sandbox.
Fit
ResearchKit is often the right choice when the app itself is the research instrument, when you have iOS developers, and when you need custom tasks or device sensors that a questionnaire platform cannot deliver. Check its current repository for supported features and maintenance status.
Capture fits studies whose needs are questionnaires, consent, site data and randomization with a controlled audit trail, and that would rather configure than commission software. It covers Phase 1 to Phase 3.
Identity and access
Site coordinators see participant names; researchers and sponsor-side users work with coded IDs. Identifying data is segregated at the database layer, sites see only their own participants, and data is encrypted with AES-256 at rest and TLS in transit, hosted in the EU or US.
Site coordinator
Jane Peterson
DOB: 04-Mar-1978
Subject 01-004
Sees direct identifiersResearcher
Subject 01-004
DOB: withheld
Coded ID only
Sees coded ID onlySame record, two roles. Row-level security enforces the split.
Switching
List the surveys and tasks in your app plan. Upload them or describe them and Capture's AI drafts the questionnaires for review; nothing is saved until you approve it. Add the schedule and completion windows.
If you already run a ResearchKit app, keep its data and documentation archived and decide per instrument whether a questionnaire will do. Active tasks that use device sensors may need to stay in an app.
Test the participant experience on real phones in the free sandbox, including reminders and consent signing, before you decide.
Evaluation
Agreements, access control and hosting checked.
Schedules, windows and reminders needed.
Audit trail with reasons required.
Consent or investigator sign-off needed.
Site separation and roles needed.
Part 11 or GCP expectations apply.
All comparisons
Every comparison uses the same approach: what to test, where each option fits, and Capture's own answers. See all of them on the comparisons hub at /compare.
An open-source framework from Apple for building research apps on iOS, with building blocks such as surveys and consent. It is a toolkit for developers, not a hosted study platform.
A framework is not a complete system. Compliance depends on the app and back end you build, the controls in them and how you validate them. Capture offers Part 11-aligned controls; compliance remains a shared responsibility.
No. You build forms in a visual builder or have AI draft them from your protocol, and participants use a browser link with no app.
No. Participants open a secure link in their phone browser, which works on iOS and Android phones without an app install.
When the app itself is the instrument, for example custom tasks or sensor data an off-the-shelf questionnaire cannot collect. Even then, consider holding the clinical record in a study system.
Capture supports connecting a participant's wearable account by native sign-in for devices the study team enables per study. Check which devices are currently available before you plan around one.
Yes. The free sandbox includes every feature with sample data, no credit card and no time limit. You pay only when you go live.
From public positioning and the criteria teams tell us matter. We state only Capture's own capabilities as fact; confirm ResearchKit's current offering with them.
Keep exploring
ePRO software for clinical trials
Questionnaires without an app.
BYOD ePRO without an app download
Which devices participants use.
eConsent software for clinical trials
Consent with verified signatures.
Capture vs ODK and KoboToolbox
Another build-or-configure question.
Capture vs Qualtrics
Survey and experience platform.
Capture vs SurveyMonkey
Online survey tool.
Build a study in minutes. Free sandbox.