PromptArmor website screenshot

PromptArmor

PromptArmor (YC W24) is an LLM application security platform that detects and blocks enterprise-grade threats - indirect prompt injection, data exfiltration, phishing, and system manipulation - in production AI applications. A real-time detection API analyzes LLM inputs and outputs against a continuously updated set of threat detectors before a completion is acted on, returning a fast verdict (for example containsInjection) so applications can block or allow content.

PromptArmor publishes 2 APIs on the APIs.io network: Analyze API and Content Check API. Tagged areas include AI, LLM, Security, Prompt Injection, and Threat Detection.

PromptArmor’s developer surface includes authentication, documentation, and 8 more developer resources.

🌐 Visit website 📡 Source on GitHub
35.2/100 thin ▬ flat Agent 31/100 agent aware Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1
AccessPaidSelf serve
2 APIs
AILLMSecurityPrompt InjectionThreat Detection

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1
Composite quality — 35.2/100 · thin
Contract Quality 15.9 / 25
Developer Ergonomics 3.9 / 20
Commercial Clarity 5.8 / 20
Operational Transparency 2.7 / 13
Governance 0.0 / 12
Discoverability 6.9 / 10
Agent readiness — 31/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/prompt-armor: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 2

Individual APIs this provider publishes, each with its own machine-readable definition.

PromptArmor Analyze API

Analyze LLM input and output through the detector engine.

PromptArmor Content Check API

Single-call content verdict against the detection engine.

Open Collections 1

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

PromptArmor API

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Prompt Armor Plans Pricing

2 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Prompt Armor Rate Limits

2 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Prompt Armor Finops

FINOPS

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Prompt Armor Authentication

apiKey · 1 scheme

SECURITY

Prompt Armor Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Prompt Armor Vulnerability Disclosure

disclosure policy published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Prompt Armor Agentic Access

3 operations · 3 acting

3 operations · 3 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess

Access & Security 3

Authentication, authorization, and security posture

VulnerabilityDisclosure
VulnerabilityDisclosure
 DomainSecurity
DomainSecurity
 Authentication
Authentication

Operate 1

Status, limits, changes, and where to get help

RateLimits
RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Plans
Plans
 FinOps
FinOps

Company 2

The organization behind the API

LinkedIn
LinkedIn
 Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: prompt-armor
url: https://raw.githubusercontent.com/api-evangelist/prompt-armor/refs/heads/main/apis.yml
name: PromptArmor
kind: company
description: PromptArmor (YC W24) is an LLM application security platform that detects and blocks enterprise-grade threats
  - indirect prompt injection, data exfiltration, phishing, and system manipulation - in production AI applications. A real-time
  detection API analyzes LLM inputs and outputs against a continuously updated set of threat detectors before a completion
  is acted on, returning a fast verdict (for example containsInjection) so applications can block or allow content.
accessModel:
  pricing: paid
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Paid · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/prompt-armor.png
tags:
- AI
- LLM
- Security
- Prompt Injection
- Threat Detection
created: '2026-06-20'
modified: '2026-06-20'
specificationVersion: '0.19'
apis:
- aid: prompt-armor:prompt-armor-analyze-api
  name: PromptArmor Analyze API
  description: Analyze LLM input and output through the detector engine.
  humanURL: https://promptarmor.readme.io/reference/post_v1-check-content
  baseURL: https://api.promptarmor.com
  tags:
  - Analyze
  properties:
  - type: OpenAPI
    url: openapi/prompt-armor-analyze-api-openapi.yml
  - type: Documentation
    url: https://promptarmor.readme.io/reference/basics-of-promptarmor-architecture
  - type: APIReference
    url: https://promptarmor.readme.io/reference/post_v1-check-content
  - type: PostmanCollection
    url: collections/prompt-armor.postman_collection.json
  - type: OpenCollection
    url: collections/prompt-armor.opencollection.json
- aid: prompt-armor:prompt-armor-content-check-api
  name: PromptArmor Content Check API
  description: Single-call content verdict against the detection engine.
  humanURL: https://promptarmor.readme.io/reference/post_v1-check-content
  baseURL: https://api.promptarmor.com
  tags:
  - Content Check
  properties:
  - type: OpenAPI
    url: openapi/prompt-armor-content-check-api-openapi.yml
  - type: Documentation
    url: https://promptarmor.readme.io/reference/basics-of-promptarmor-architecture
  - type: APIReference
    url: https://promptarmor.readme.io/reference/post_v1-check-content
  - type: PostmanCollection
    url: collections/prompt-armor.postman_collection.json
  - type: OpenCollection
    url: collections/prompt-armor.opencollection.json
common:
- type: AgenticAccess
  url: agentic-access/prompt-armor-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/prompt-armor-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/prompt-armor-domain-security.yml
- type: Authentication
  url: authentication/prompt-armor-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/promptarmor
- type: Website
  url: https://www.promptarmor.com/
- type: Documentation
  url: https://promptarmor.readme.io/
- type: Plans
  url: plans/prompt-armor-plans-pricing.yml
- type: RateLimits
  url: rate-limits/prompt-armor-rate-limits.yml
- type: FinOps
  url: finops/prompt-armor-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com