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Research · head to head

Castor EDC vs Marvin

Castor EDC logo

Castor EDC

Research

Electronic data capture and eConsent for clinical trials, built for investigator-initiated studies as well as sponsors

From
On request
Rated
-
Full reviewWebsite
Marvin logo

Marvin

Research

Qualitative research repository with AI notetaking, and an MCP server you can query from Claude

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Marvin has a free tier, so it costs nothing to try first.
  • Each has a real cost: Castor EDC nothing is published: pricing is quoted only after a scoping call and protocol review, so budgeting a grant application means asking for a quote months before the study is funded and hoping the scope holds.; Marvin transcription is inconsistent, with missing punctuation and specifically poor Portuguese accuracy reported, so non-English research teams spend the time cleaning up that the licence was meant to save.
  • They diverge on capability: Castor EDC covers Browser-based study build, Marvin covers AI Notetaker.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Castor EDC and Marvin actually diverge.

Attributes where Castor EDC and Marvin differ
AttributeCastor EDCMarvin
Starting priceOn requestFree
Free tierNoYes
PlatformsWeb, iOS, AndroidWeb

Identical on both: pricing model (quote), user rating (Not yet rated), category (Research).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Castor EDC

  • Browser-based study build
  • 21 CFR Part 11 workflows
  • eConsent
  • ePRO and surveys
  • Randomisation
  • Per-study licensing
  • Grant-funded pricing paths
  • Data export

Only in Marvin

  • AI Notetaker
  • AI Moderated Interviewer
  • Ask AI
  • Deep Research
  • Thematic and emotion analysis
  • Clips and highlight reels
  • Virtual observation room
  • MCP server and API

What people use each for

The jobs each tool is most often brought in to do.

Castor EDC

  • An academic hospital running an investigator-initiated trial that cannot fund a sponsor-grade EDC contract or a data management CROnot Marvin
  • A medical device company collecting post-market clinical follow-up data with Part 11 audit trailsnot Marvin
  • A multi-site registry that needs remote eConsent because participants are recruited nationally rather than at a clinicnot Marvin
  • A biotech running a small phase two study that wants the database built by its own clinical team in weeks rather than commissionednot Marvin

Marvin

  • A two-person research team that needs interviews transcribed, tagged and searchable without hiring an analyst or buying an enterprise repository.not Castor EDC
  • A product organisation where findings are never read, wanting product managers to query past research from Claude or ChatGPT instead of logging into a research tool.not Castor EDC
  • A team running discovery at volume that wants an AI moderator to conduct unmoderated interviews overnight and have them analysed by morning.not Castor EDC
  • A researcher who needs to send stakeholders a highlight reel of customer quotes rather than a slide deck summarising them.not Castor EDC

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Castor EDC

  • Nothing is published: pricing is quoted only after a scoping call and protocol review, so budgeting a grant application means asking for a quote months before the study is funded and hoping the scope holds.
  • Price scales on protocol complexity rather than a simple unit, so two studies with the same participant count can be quoted very differently and there is no public benchmark to argue against.
  • Modules such as eConsent, ePRO and randomisation are quoted on top of the base platform, so the headline EDC figure is rarely the number that appears on the final proposal.
  • It is deliberately lighter than the full sponsor suites, so a study that grows into a global registrational programme needing integrated CTMS, safety, IRT and full trial supply management will need additional systems and the interfaces between them.
  • Regulatory responsibility does not transfer with the software: the platform supports Part 11 compliant workflows, but system validation for your intended use, SOPs and audit readiness remain your obligation and your cost, which sponsors new to EDC consistently underestimate.

Marvin

  • Transcription is inconsistent, with missing punctuation and specifically poor Portuguese accuracy reported, so non-English research teams spend the time cleaning up that the licence was meant to save.
  • Speaker diarisation errors attribute moderator speech to the participant, and a misattributed quote propagates into themes and into the insight report you show stakeholders, which is a research credibility risk rather than a cosmetic bug.
  • SSO, EU or US data residency, PII redaction and a HIPAA BAA are bundled into a paid Compliance add-on available only from Pro upwards, so the headline Pro quote is never the real price for a regulated or European buyer.
  • Starter includes only two full seats, so a four-researcher team is forced to Pro on seat count alone, and the three-way split between full, collaborator and viewer seats makes cost modelling awkward when no paid tier is priced publicly.
  • Every paid tier is sales-gated with annual commitment typically required, so there is no monthly paid trial and no published seat cost to budget against before entering a sales cycle.
  • Integration coverage has gaps, with no Intercom connector despite repeated requests from teams wanting support conversations in the same repository, and reviewers describe the tags versus labels distinction in the interface as confusing.

Pricing, plan by plan

Castor EDC

On request
  • Castor EDC$undefined/year
    • Priced per study on protocol complexity, duration, sites and modules
    • 21 CFR Part 11 and ICH GCP workflows
    • eConsent, ePRO and randomisation modules quoted separately

Marvin

Free
  • FreeFree
    • 2 full seats and 3 collaborator seats
    • 5 file uploads per month
    • AI notetaking and transcription
  • Starter$undefined/year
    • 2 full seats, 10 collaborator seats, 50 viewer seats
    • Unlimited uploads
    • Thematic analysis
  • Pro$undefined/year
    • 5 full seats, 15 collaborator seats, 100 viewer seats
    • Agentic Ask AI and Deep Research
    • Marvin MCP server and API
  • Enterprise$undefined/year
    • 5 full seats, 15 collaborator seats, unlimited viewer seats
    • Salesforce integration included
    • Dedicated support

Which should you pick?

Choose Castor EDC if

  • You need browser-based study build.
  • You work on Web, iOS, Android.
  • You also want 21 cfr part 11 workflows.
Castor EDC review

Choose Marvin if

  • You need ai notetaker.
  • You want to start without paying.
  • You also want ai moderated interviewer.
Marvin review

Questions people ask

Is Castor EDC or Marvin better?
Neither clearly leads. Castor EDC starts at On request and Marvin at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Castor EDC or Marvin?
Marvin has a free tier; the other does not. Paid plans start at On request for Castor EDC and Free for Marvin.
Does Castor EDC or Marvin run on more platforms?
Castor EDC runs on Web, iOS, Android. Marvin runs on Web.
Can I use Marvin for free?
Yes. Marvin has a free tier, so you can try it without paying. Castor EDC starts at On request.
What is Castor EDC best used for?
Castor EDC is most often used for an academic hospital running an investigator-initiated trial that cannot fund a sponsor-grade edc contract or a data management cro, a medical device company collecting post-market clinical follow-up data with part 11 audit trails, a multi-site registry that needs remote econsent because participants are recruited nationally rather than at a clinic, a biotech running a small phase two study that wants the database built by its own clinical team in weeks rather than commissioned. Of those, an academic hospital running an investigator-initiated trial that cannot fund a sponsor-grade edc contract or a data management cro and a medical device company collecting post-market clinical follow-up data with part 11 audit trails are not what Marvin is typically brought in for.
What can Castor EDC do that Marvin cannot?
Castor EDC covers Browser-based study build, 21 CFR Part 11 workflows, eConsent, ePRO and surveys. Marvin covers AI Notetaker, AI Moderated Interviewer, Ask AI, Deep Research.

Answered from the vendors’ own pages

Castor EDC: Is there a free academic version?

No published free tier. There are academic, non-profit and grant-funded pricing paths, but each is quoted rather than self-service.

Marvin: Is there a genuinely free plan?

Yes. Two full seats, three collaborator seats and five file uploads a month at no cost. It is enough to evaluate the analysis quality on real interviews.

Castor EDC: Is it 21 CFR Part 11 compliant?

It supports Part 11 compliant workflows with audit trails and electronic signatures. Validating the system for your specific use remains your responsibility.

Marvin: What does Pro cost?

Not published. Only the Free tier carries a price. Starter, Pro and Enterprise are all quoted.

Castor EDC: Do I need a programmer to build a study?

No. Case report forms are configured in the browser, which is the main reason academic groups adopt it.

Marvin: Can I get SSO and EU data residency?

Yes, but as a separately priced Compliance add-on from Pro upwards, not included in any base tier. Price it into the quote from the start.

Castor EDC: How long does a quote take?

Castor states a full pricing proposal within five business days of sharing the protocol.

Marvin: What is the MCP server for?

It lets Claude, ChatGPT or Copilot query your research repository directly with cited answers, so stakeholders get findings without opening Marvin.

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