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Research · head to head

Castor EDC vs Zappi

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
Zappi logo

Zappi

Research

Automated consumer insights platform for testing advertising, product concepts and brand health

From
On request
Rated
-
Full reviewWebsite

The short version

  • 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.; Zappi nothing is published: pricing is a platform subscription plus a prepaid credit bundle quoted per customer, so a buyer cannot benchmark the cost against agency research without going through sales.
  • They diverge on capability: Castor EDC covers Browser-based study build, Zappi covers Validated study templates.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

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

Attributes where Castor EDC and Zappi differ
AttributeCastor EDCZappi
PlatformsWeb, iOS, AndroidWeb

Identical on both: starting price (On request), pricing model (quote), free tier (No), 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 Zappi

  • Validated study templates
  • Respondent panel access
  • Normative benchmarks
  • Creative testing
  • Brand health tracking
  • AI analysis over history
  • Unlimited users
  • Exports and integrations

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 Zappi
  • A medical device company collecting post-market clinical follow-up data with Part 11 audit trailsnot Zappi
  • A multi-site registry that needs remote eConsent because participants are recruited nationally rather than at a clinicnot Zappi
  • A biotech running a small phase two study that wants the database built by its own clinical team in weeks rather than commissionednot Zappi

Zappi

  • A beverage brand screening thirty flavour concepts before committing to two for consumer testingnot Castor EDC
  • A marketing team pre-testing three advertising edits in a day so a media booking deadline can be metnot Castor EDC
  • An insights function replacing repeated ad-hoc agency studies with a comparable, accumulating body of test resultsnot Castor EDC
  • A brand manager running continuous brand health tracking without negotiating a separate tracker contract each yearnot 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.

Zappi

  • Nothing is published: pricing is a platform subscription plus a prepaid credit bundle quoted per customer, so a buyer cannot benchmark the cost against agency research without going through sales.
  • Credits are prepaid against a forecast of the year ahead, which means a team that overestimates research volume ends the year having paid for studies it never ran.
  • The template model that makes studies fast also constrains them; a research question that does not fit a validated instrument either gets forced into one or goes to an agency anyway.
  • Normative benchmarks are strongest in fast-moving consumer goods categories where Zappi has depth, and thinner in business-to-business, financial services and niche categories, where the comparison numbers mean less.
  • Because respondents come from Zappi-sourced panels, sample composition is a vendor decision rather than yours, and any team that needs a bespoke recruitment specification or a low-incidence audience will find the automated route unsuitable.

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

Zappi

On request
  • Premium$undefined/year
    • Platform subscription with unlimited users
    • Access to all research solutions
    • Credit bundle scoped to annual research volume
  • Enterprise$undefined/year
    • Platform subscription with unlimited users
    • Multi-market and global organisation controls
    • Connected insights across markets and brands

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 Zappi if

  • You need validated study templates.
  • You also want respondent panel access.
Zappi review

Questions people ask

Is Castor EDC or Zappi better?
Neither clearly leads. Castor EDC starts at On request and Zappi at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Castor EDC or Zappi?
Castor EDC starts at On request and Zappi at On request.
Does Castor EDC or Zappi run on more platforms?
Castor EDC runs on Web, iOS, Android. Zappi runs on Web.
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 Zappi is typically brought in for.
What can Castor EDC do that Zappi cannot?
Castor EDC covers Browser-based study build, 21 CFR Part 11 workflows, eConsent, ePRO and surveys. Zappi covers Validated study templates, Respondent panel access, Normative benchmarks, Creative testing.

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.

Zappi: Does Zappi publish prices?

No. It publishes the structure, a platform subscription plus credits plus optional services, but not the numbers.

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.

Zappi: How fast do results come back?

Automated tests typically return within hours to a day, which is the main reason teams choose it over a commissioned study.

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.

Zappi: Do we still need an agency?

For standard concept, creative and brand tests, usually not. For bespoke methodologies and hard-to-reach audiences, yes.

Castor EDC: How long does a quote take?

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

Zappi: Is there a per-seat charge?

No. Both published tiers include unlimited users; the variable cost is research credits.

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