REDCap and Castor are two of the names academic researchers meet most often. They come from very different models: one licensed to institutions through a consortium and hosted locally, the other a commercial cloud service. Here is how to choose, and when a third option fits better.
Free sandbox · No credit card · 21 CFR Part 11 aligned
| REDCap | Castor | Capture | |
|---|---|---|---|
| Commercial model | Consortium licence | Subscription | Pay when live |
| Who hosts | Your institution | Vendor cloud | Capture (EU or US) |
| Who supports users | Local admins | Vendor | Capture |
| Self-serve sign-up | Via institution | Ask vendor | |
| Free full sandbox | Via institution | Ask vendor |
The short version
Two models
The biggest difference between REDCap and Castor is not a feature: it is who runs the software. With REDCap, your institution joins the consortium, installs and maintains the system, and usually has a local team that supports researchers, approves projects and manages accounts. Researchers often get it at no direct cost to their study, and the institution carries the hosting, upgrade and validation work.
With a commercial cloud platform such as Castor, the vendor hosts and maintains the system, and your study or institution pays a subscription. Support comes from the vendor. You depend less on local IT capacity, but you need a contract, a budget line and vendor due diligence.
If your institution runs REDCap and supports it well, it is often the path of least resistance for surveys, registries and simple studies. If it does not, or if your study involves multiple institutions, commercial sponsorship or regulated trial requirements your local installation is not set up for, a hosted platform can be simpler.
Neither model is automatically Part 11 or Annex 11 compliant: compliance depends on the system's controls plus how it is configured, validated and used. With a locally hosted system, ask your institution what validation and procedures are in place. With any vendor, ask for the documentation that supports your validation. The Part 11 compliance checklist lists what to look for.
Deciding
| Question | Points towards |
|---|---|
| Does my institution already run and support REDCap? | REDCap, if support is good. |
| Is my study a survey, registry or simple observational project? | Either; often the institution's default. |
| Does the study need ePRO, eConsent and randomisation together? | A platform that includes them in one system; check each option. |
| Is a commercial sponsor involved, or are regulated trial controls required? | Whichever option can document its controls and support your validation. |
| Will partners at other institutions need access? | A hosted platform often simplifies cross-institution access. |
| Do I have budget for a subscription? | Cost model matters: institutional licence versus subscription versus pay when live. |
A third option
Capture is a hosted platform that researchers can start using without an institutional install or a sales call. Build the full study in a free sandbox, with EDC, ePRO, eConsent and randomisation in one system, and pay only when the study goes live with real participants. Data is hosted in the EU (Frankfurt) or the US (N. Virginia).
Question form
CRF or ePRO
Lab table
Analytes, units, ranges
1. Systolic blood pressure
Required · Number · mmHg · 0 dp
2. Diastolic blood pressure
Required · Number · mmHg · 0 dp
3. Pulse rate
Required · Number · beats/min
4. Body temperature
Required · Number · °C · 1 dp
5. Position during measurement
Required · Sitting, Supine, Standing
Upload your data dictionary to the free sandbox and review the draft.
Beyond data entry
The REDCap versus Castor question is often really a question about everything around data entry. Many studies also need electronic consent with verifiable signatures, questionnaires that participants complete on their own phones, randomisation, and a way for monitors to verify data. Each of those can be a separate tool, an add-on or part of the same platform, and the answer changes the comparison.
List what your study needs before comparing: forms and edit checks, consent, ePRO, randomisation, multi-site access, exports for your statistician, and any regulatory requirements. Then check how each option covers the list, and what is left for other tools. Every additional system adds a login for sites, an integration to maintain and a separate audit trail to reconcile.
Whatever you choose, make sure you can export your data, data dictionary and audit trail in open formats. It keeps your options open for the next study, and it is what regulators and journals increasingly expect.
Deciding
EDC, consent, ePRO, randomisation, multi-site access and exports.
What your institution already licenses and supports.
Whether Part 11, Annex 11 or GCP-grade controls are required.
How collaborators at other institutions will log in.
Institutional licence, subscription or pay when live.
Open-format exports of data, dictionary and audit trail.
REDCap is made available at no licence cost to non-profit institutions that join the REDCap Consortium. The institution carries the cost of hosting, maintaining and supporting it.
Castor is a commercial platform. Ask the vendor directly about current plans and pricing.
It depends on your institution's REDCap setup, whether regulated trial controls are required, whether you need ePRO and eConsent in the same system, and your budget.
Part 11 compliance depends on the system's controls and on how it is configured, validated and used. With a locally hosted REDCap, ask your institution what validation is in place.
Yes. Export the REDCap data dictionary and the AI form builder drafts the forms for review. Most teams start new studies in Capture rather than switching mid-study.
Yes. The free sandbox has every feature with no credit card.
Keep exploring
EDC, ePRO, eConsent and randomisation in one self-serve system.