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Research · head to head

Castor EDC vs Terra

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
Terra logo

Terra

Research

Open biomedical research platform for genomic analysis, priced only by the cloud you consume

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Terra 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.; Terra the absence of a licence fee hides the real cost driver: an idle notebook virtual machine left running overnight, or a workspace bucket full of intermediate workflow outputs, quietly consumes grant money with no vendor invoice to prompt a review.
  • They diverge on capability: Castor EDC covers Browser-based study build, Terra covers No platform licence fee.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

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

Attributes where Castor EDC and Terra differ
AttributeCastor EDCTerra
Starting priceOn requestFree
Pricing modelquoteOpen source, no licence fee
Free tierNoYes
PlatformsWeb, iOS, AndroidWeb, Google Cloud, Microsoft Azure

Identical on both: 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 Terra

  • No platform licence fee
  • Cloud pass-through billing
  • WDL workflow execution
  • Notebook environments
  • Controlled-access data
  • Workspace sharing
  • Compliance posture
  • Multi-cloud

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

Terra

  • A genomics lab running whole-genome alignment and variant calling pipelines without provisioning or maintaining a local clusternot Castor EDC
  • A consortium sharing controlled-access human data across institutions where the data cannot be copied to each sitenot Castor EDC
  • A health system analysing patient genomic data under a HIPAA business associate agreementnot Castor EDC
  • A federal or federally funded project needing FedRAMP Moderate authorisation for its analysis environmentnot 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.

Terra

  • The absence of a licence fee hides the real cost driver: an idle notebook virtual machine left running overnight, or a workspace bucket full of intermediate workflow outputs, quietly consumes grant money with no vendor invoice to prompt a review.
  • Cost governance is entirely the customer responsibility, and grant-funded groups without a cloud engineer routinely overspend before anyone reads the Google or Azure bill in enough detail to find the cause.
  • It assumes genuine bioinformatics competence: writing or adapting WDL workflows, managing data tables and debugging failed tasks are all on you, so a wet lab without computational staff cannot use it productively.
  • Feature parity between the Google Cloud and Azure deployments is not identical, so a decision on cloud provider constrains which capabilities and datasets you can reach and is expensive to reverse later.
  • It is a research platform rather than a regulated clinical system: it is not a validated GxP environment and does not carry the qualification package a diagnostic or submission workflow would require, so clinical use needs additional infrastructure and validation you provide yourself.

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

Terra

Free
  • Terra platformFree
    • No charge for the platform, administration, security controls or frontline support
    • Workspaces, workflow execution and notebook environments included
    • Available on Google Cloud and Microsoft Azure
  • Cloud consumption$undefined/month
    • Google Cloud or Azure charges passed through at cost with no markup
    • Running notebook virtual machines around 0.22 USD per hour, roughly 0.027 USD per hour when paused
    • Storage billed continuously on workspace buckets and intermediate workflow outputs

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 Terra if

  • You need no platform licence fee.
  • You want to start without paying.
  • You work on Web, Google Cloud, Microsoft Azure.
  • You also want cloud pass-through billing.
Terra review

Questions people ask

Is Castor EDC or Terra better?
Neither clearly leads. Castor EDC starts at On request and Terra at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Castor EDC or Terra?
Terra has a free tier; the other does not. Paid plans start at On request for Castor EDC and Free for Terra.
Does Castor EDC or Terra run on more platforms?
Castor EDC runs on Web, iOS, Android. Terra runs on Web, Google Cloud, Microsoft Azure.
Can I use Terra for free?
Yes. Terra 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 Terra is typically brought in for.
What can Castor EDC do that Terra cannot?
Castor EDC covers Browser-based study build, 21 CFR Part 11 workflows, eConsent, ePRO and surveys. Terra covers No platform licence fee, Cloud pass-through billing, WDL workflow execution, Notebook environments.

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.

Terra: Is Terra really free?

The platform is. There is no licence fee. Everything you pay is Google Cloud or Azure compute, storage and egress, passed through at cost.

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.

Terra: What actually drives the bill?

Running virtual machines and stored data. Pausing notebooks drops a virtual machine from about 0.22 to about 0.027 dollars an hour, and deleting intermediate workflow outputs is the other main saving.

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.

Terra: Can I use it with protected health information?

Yes. Terra signs HIPAA business associate agreements and GDPR data processing agreements, and the Azure deployment holds FedRAMP Moderate authorisation.

Castor EDC: How long does a quote take?

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

Terra: Is it validated for clinical or GxP use?

No. It is a research platform. Regulated clinical or submission workflows need validation and controls you build yourself.

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