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Cybersecurity · head to head

BigID vs Tenable Nessus

BigID logo

BigID

Cybersecurity

Data discovery and classification across cloud, on-premise and unstructured stores

From
On request
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Tenable Nessus has a free tier, so it costs nothing to try first.
  • Each has a real cost: BigID pricing scales with data sources and volume, so the cost rises exactly as the estate you need to scan grows, and the modules shown in a demo, including AI security posture and headless deployment, are frequently separate licences that appear only in the final quote.; Tenable Nessus nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • They diverge on capability: BigID covers Structured and unstructured scanning, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which BigID and Tenable Nessus actually diverge.

Attributes where BigID and Tenable Nessus differ
AttributeBigIDTenable Nessus
Starting priceOn requestFree
Pricing modelquotesubscription
Free tierNoYes
PlatformsWeb, API, Self-hostedWindows, Linux, Macos, Cloud
FoundedUnknown2002

Identical on both: user rating (Not yet rated), category (Cybersecurity).

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 BigID

  • Structured and unstructured scanning
  • Identity correlation
  • Data security posture management
  • Access intelligence
  • Privacy request support
  • Retention and minimisation
  • AI data controls
  • Policy and remediation workflow

Only in Tenable Nessus

  • Network scanning
  • Vulnerability detection
  • Configuration assessment
  • Malware detection
  • Compliance checking
  • Cloud security assessment
  • Mobile scanning
  • API access

What people use each for

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

BigID

  • A bank that has to prove which of thirty year old file shares contain customer identifiers before a data centre migrationnot Tenable Nessus
  • A privacy team that cannot fulfil deletion requests because nobody knows which unstructured stores hold a given customer’s recordsnot Tenable Nessus
  • A security team wanting to find sensitive data sitting in publicly readable object storage buckets before an attacker doesnot Tenable Nessus
  • A company building retrieval augmented AI that must exclude regulated personal data from the index it feeds to a modelnot Tenable Nessus

Tenable Nessus

  • Vulnerability scanning of servers, network devices and web applicationsnot BigID
  • Configuration and compliance auditing against hardening benchmarksnot BigID
  • Point in time assessments by consultants and penetration testersnot BigID

Where each one falls short

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

BigID

  • Pricing scales with data sources and volume, so the cost rises exactly as the estate you need to scan grows, and the modules shown in a demo, including AI security posture and headless deployment, are frequently separate licences that appear only in the final quote.
  • Scanning large unstructured estates is slow and computationally expensive, so most organisations sample rather than scan everything, which reintroduces uncertainty into the very question they bought the tool to settle.
  • Classification accuracy on messy unstructured content requires tuning, and out of the box false positives on things like reference numbers create a large triage backlog that a small governance team cannot clear.
  • It discovers and reports but does not remediate, so realising value requires a separate process and often separate tooling to actually delete, restrict or move the data it flags.
  • It is built for large enterprises and both the price and the administrative overhead are disproportionate below a few thousand employees, where a lighter DSPM tool covers the security use case for far less.

Tenable Nessus

  • Nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • Support beyond the base entitlement costs an extra $400 per year for Advanced Support with 24x365 phone and chat access
  • The on demand training course is a separate $275 purchase for a single person for one year
  • Multi year discounts require paying for two or three years up front

Pricing, plan by plan

BigID

On request
  • BigID Platform$undefined/year
    • Priced by number of data sources and data volume
    • Discovery and classification core
    • Optional DSPM, access intelligence and AI security modules licensed separately

Tenable Nessus

Free
  • Nessus EssentialsFree
    • Up to 16 ips
    • Network scanning
    • Vulnerability assessment
  • Nessus Professional$2600/year
    • Unlimited targets
    • Enterprise features
    • Advanced analytics
  • Nessus Expert$5200/year
    • All Professional features
    • Cloud integration
    • Advanced reporting

Which should you pick?

Choose BigID if

  • You need structured and unstructured scanning.
  • You work on Web, API, Self-hosted.
  • You also want identity correlation.
BigID review

Choose Tenable Nessus if

  • You need network scanning.
  • You want to start without paying.
  • You work on Windows, Linux, Macos, Cloud.
  • You also want vulnerability detection.
Tenable Nessus review

Questions people ask

Is BigID or Tenable Nessus better?
Neither clearly leads. BigID starts at On request and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, BigID or Tenable Nessus?
Tenable Nessus has a free tier; the other does not. Paid plans start at On request for BigID and Free for Tenable Nessus.
Does BigID or Tenable Nessus run on more platforms?
BigID runs on Web, API, Self-hosted. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Tenable Nessus for free?
Yes. Tenable Nessus has a free tier, so you can try it without paying. BigID starts at On request.
What is BigID best used for?
BigID is most often used for a bank that has to prove which of thirty year old file shares contain customer identifiers before a data centre migration, a privacy team that cannot fulfil deletion requests because nobody knows which unstructured stores hold a given customer’s records, a security team wanting to find sensitive data sitting in publicly readable object storage buckets before an attacker does, a company building retrieval augmented ai that must exclude regulated personal data from the index it feeds to a model. Of those, a bank that has to prove which of thirty year old file shares contain customer identifiers before a data centre migration and a privacy team that cannot fulfil deletion requests because nobody knows which unstructured stores hold a given customer’s records are not what Tenable Nessus is typically brought in for.
What can BigID do that Tenable Nessus cannot?
BigID covers Structured and unstructured scanning, Identity correlation, Data security posture management, Access intelligence. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

Answered from the vendors’ own pages

BigID: What does BigID cost?

It is quoted by data source count and volume. Reported contracts run from roughly 15,000 to 175,000 US dollars a year, and add-on modules such as AI security posture are licensed on top.

Tenable Nessus: What are the three Nessus offerings?

Nessus Essentials is a free introductory offering for educators, students, and career starters, limited to 16 IPs for scanning. Nessus Professional is designed for consultants and SMBs, providing unlimited IT scans across any location. Nessus Expert is the premium offering extending Professional with web application scanning, infrastructure-as-code scanning, and external attack surface assessment up to 5 domains.

Source
BigID: Does it handle unstructured data?

Yes, and that is its main advantage. It classifies data in files and shares and correlates findings back to individuals, not just to data types.

Tenable Nessus: What OS platforms does Nessus support?

Nessus runs on Debian/Kali Linux, Fedora, FreeBSD, Mac OS X, Red Hat/CentOS, SUSE Linux, Ubuntu, and various Windows versions including Server 2008, 2012, and Windows 7-10.

Source
BigID: Will it delete the data it finds?

Not by itself in most deployments. It identifies and routes findings; deletion and remediation happen through your own processes or connected systems.

Tenable Nessus: Can I use Nessus to scan third-party networks as a consultant?

Yes, Tenable permits you to use Nessus to scan third-party networks. Nessus Professional is ideal for consultants.

Source
BigID: Is it a privacy tool or a security tool?

Both are sold from the same discovery core. Buyers increasingly come from security wanting data security posture management rather than from legal wanting privacy.

Tenable Nessus: Can Nessus perform PCI external scanning?

Yes, you can use Nessus Professional to perform external network scans as required by the PCI DSS 11.2.2 requirement.

Source
Tenable Nessus: What additional features does Nessus Expert provide?

Web application scanning, which is dynamic application security testing (DAST) providing comprehensive visibility and insight into web application security issues; scanning code repositories for vulnerabilities; and assessing external attack surface with subdomain discovery.

Source
Tenable Nessus: What support options exist for Nessus Professional?

Standard Support includes software upgrades, patches, plugin access, and 24x7 support via chat and community portal. Advanced Support adds 24x7 phone access and committed SLAs: P1 less than 2 hours, P2 less than 4 hours, P3 less than 12 hours, P4 less than 24 hours.

Source
Tenable Nessus: How frequently are Nessus plugins updated?

Nessus plugins are updated daily, based on when vendors and security research sites publish new vulnerabilities.

Source
Tenable Nessus: How does licensing work in virtual machine environments?

Whether you are using Nessus in a physical or a virtual environment, the IP addresses or hosts that you are scanning from must be licensed.

Source
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