# Data Theorem API Security vs RealmGuard: side-by-side comparison (2026)

[Data Theorem API Security](https://cybersectools.com/tools/data-theorem-api-security) is a commercial [API security](https://cybersectools.com/categories/api-security) solution by [Data Theorem](https://cybersectools.com/companies/data-theorem). [RealmGuard](https://cybersectools.com/tools/realm-labs-platform) is a commercial [LLM guardrails](https://cybersectools.com/categories/llm-guardrails) solution by [Realm Labs](https://cybersectools.com/companies/realm-labs). Features, integrations, deployment and the company behind each one, side by side.

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## Side-by-side comparison

| | Data Theorem API Security | RealmGuard |
|---|---|---|
| Pricing model | Commercial | Commercial |
| Category | API Security | LLM Guardrails |
| Verified | No | No |
| Deployment type | Hybrid | Hybrid |
| Company size fit | SMB, Mid-Market, Enterprise | SMB, Mid-Market, Enterprise |
| Company | Data Theorem | Realm Labs |
| Headquarters | – | – |

### Use cases and capabilities

| | Data Theorem API Security | RealmGuard |
|---|---|---|
| Bot Protection | Yes | – |
| DAST | Yes | – |
| LLM Guardrails | – | Yes |
| LLM Security | – | Yes |
| Prompt Injection | – | Yes |
| AI Firewall | – | Yes |
| GenAI Security | – | Yes |
| Content Filtering | – | Yes |
| PII | – | Yes |
| AI Compliance | – | Yes |
| AI Governance | – | Yes |
| OWASP | – | Yes |

### Core features

**Data Theorem API Security**

10 features listed. Sign in on the page to see them.

**RealmGuard**

10 features listed. Sign in on the page to see them.

### Integrations

**Data Theorem API Security**

13 integrations listed. Sign in on the page to see them.

**RealmGuard**

No integrations listed.

## Data Theorem API Security vs RealmGuard FAQ

Common questions when comparing Data Theorem API Security vs RealmGuard for API security.

### What is the difference between Data Theorem API Security and RealmGuard?

**Data Theorem API Security**: API security platform for discovery, testing, and runtime protection. Built by Data Theorem.

**RealmGuard**: AI guardrail platform detecting harmful outputs, prompt injections & policy violations. Built by Realm Labs.

The table above shows where their features, integrations, deployment and company size fit differ.

### Who makes Data Theorem API Security and RealmGuard?

**Data Theorem API Security** is made by Data Theorem. **RealmGuard** is made by Realm Labs. The vendor behind a product decides its roadmap, support, and longevity, so check each company's profile before you commit.

### Is Data Theorem API Security a good alternative to RealmGuard?

In part. Data Theorem API Security and RealmGuard are not in the same category on CybersecTools. Use the table above to see where features, deployment and company size fit differ.

## Related comparisons

- [Data Theorem API Security vs Indusface AppTrana - API Protection](https://cybersectools.com/compare/data-theorem-api-security-vs-indusface-apptrana-api-protection)
- [Data Theorem API Security vs Ammune API Discovery](https://cybersectools.com/compare/ammune-api-discovery-vs-data-theorem-api-security)
- [Data Theorem API Security vs Wallarm API Security](https://cybersectools.com/compare/data-theorem-api-security-vs-wallarm-api-security)
- [RealmGuard vs Indusface AppTrana - API Protection](https://cybersectools.com/compare/indusface-apptrana-api-protection-vs-realm-labs-platform)
- [RealmGuard vs Ammune API Discovery](https://cybersectools.com/compare/ammune-api-discovery-vs-realm-labs-platform)
- [RealmGuard vs Wallarm API Security](https://cybersectools.com/compare/realm-labs-platform-vs-wallarm-api-security)

## Alternatives to each

- [See all Data Theorem API Security alternatives](https://cybersectools.com/alternatives/data-theorem-api-security)
- [See all RealmGuard alternatives](https://cybersectools.com/alternatives/realm-labs-platform)

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Source: https://cybersectools.com/compare/data-theorem-api-security-vs-realm-labs-platform

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More on Data Theorem API Security and RealmGuard: funding, momentum, hiring and news, plus the full product and company record, are available through the Mandos MCP Server (paid plans), which connects to AI assistants: https://mandos.io/mcp?utm_source=cybersectools.com&utm_medium=compare-md