canonical: https://jentic.com/apis/usercheck.com/usercheck

# UserCheck API

An API designed to help businesses and developers detect and block disposable (temporary) email addresses. The API exposes 8 endpoints secured with bearer authentication.

## For AI agents

Programmatically validate email address, validate domain. Covers 8 operations with bearer authentication.

## Scope

Does not handle payments, crm, or developer tools - use for communications only.

## Capabilities

- Validate email address
- Add domain to blocklist
- List blocklisted domains
- Bulk add domains to blocklist
- Check domain blocklist status
- Remove domain from blocklist

## Use cases

### Communications Operations

Use the UserCheck API to perform communications operations programmatically. The API provides 8 endpoints covering core functionality including validate email address, validate domain, add domain to blocklist.

Example prompt: Call GET `/email/{email}` to validate email address

### Automated blocklist Management

Automate blocklist operations by combining multiple UserCheck API endpoints. Agents can validate domain and then add domain to blocklist in a single workflow.

Example prompt: Call GET `/domain/{domain}` to validate domain, then verify the result

### AI Agent Integration via Jentic

AI agents discover and call UserCheck API endpoints through Jentic without managing credentials directly. An agent searches for the required operation by intent, receives the matching endpoint schema, and executes the call with Jentic-managed authentication. This eliminates the need to read API documentation or handle bearer tokens manually.

Example prompt: Search Jentic for 'validate email address', load the operation schema, and execute with Jentic-managed credentials

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| GET | `/email/{email}` | Validate email address |
| GET | `/domain/{domain}` | Validate domain |
| POST | `/blocklist` | Add domain to blocklist |
| GET | `/blocklist` | List blocklisted domains |
| POST | `/blocklist/bulk` | Bulk add domains to blocklist |
| GET | `/blocklist/{domain}` | Check domain blocklist status |
| DELETE | `/blocklist/{domain}` | Remove domain from blocklist |
| GET | `/status` | Get API status |

## Key resources

- **blocklist** — Operations related to blocklist
- **domain** — Operations related to domain
- **email** — Operations related to email
- **status** — Operations related to status

## AI readiness

This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.

- **Score:** 67 / 100
- **Maturity:** AI-Aware
- **Dimensions:**
  - Foundational Compliance: 87 / 100
  - Developer Experience & Jentic Compatibility: 63 / 100
  - AI-Readiness & Agent Experience: 50 / 100
  - Agent Usability: 94 / 100
  - Security: 60 / 100
  - AI Discoverability: 78 / 100
- **View full report:** https://jentic.com/apis/usercheck.com/usercheck/scorecard
- **How the score is calculated:** https://docs.jentic.com/reference/api-readiness-framework/overview/
- **More about the dimensions:** https://docs.jentic.com/reference/api-readiness-framework/specification/#dimensional-model-overview

### Score it yourself

Every API in the directory is allowlisted, so you can re-score it with no key required.

- **Score your own API:** https://jentic.com/scorecard.md
- **Scoring CLI agent skill:** https://github.com/jentic/jentic-api-scorecard/blob/main/skills/jentic-api-scorecard/SKILL.md

```sh
npx @jentic/api-scorecard-cli score <openapi-url>
```

## Why Jentic

- **Setup:** Wiring the UserCheck API by hand means attaching its bearer token, encoding the email or domain into the path, and maintaining your blocklist through separate calls yourself. Through Jentic you install once, import UserCheck from the API Directory, store the token once, and your agent calls it.
- **Permission scoping:** UserCheck puts the domain in the URL path (`/blocklist/{domain}`), so a rule can pin your agent to one domain's blocklist entry: it can read that entry if you allow it. You choose the operations it may call, so blocklist deletion is not included unless you add it.
- **Credential handling:** Your UserCheck token is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'validate an email address' or 'check a domain', and Jentic returns the matching UserCheck operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Twilio** — Alternative communications API
- **Sendgrid** — Alternative communications API
- **Pusher** — Complementary communications API

## FAQ

### What authentication does the UserCheck API use?

The UserCheck API uses a Bearer token in the Authorization header. Through Jentic, these credentials are stored encrypted in your Jentic One instance and injected at execution time, so raw secrets never enter the agent context.

### Can I validate email address with the UserCheck API?

Yes. Use the GET `/email/{email}` endpoint. The API returns structured JSON responses that agents can parse and act on directly.

### What are the rate limits for the UserCheck API?

Rate limits are not specified in the OpenAPI spec. Check the vendor documentation for current limits. Through Jentic, rate limiting is handled automatically with retry logic built into the execution layer.

### How do I validate email address through Jentic?

Install the Jentic SDK with pip install jentic, authenticate through Jentic One, the self-hosted execution layer, then search for 'validate email address'. Jentic returns the matching UserCheck API operation with its input schema. Load the schema and execute the call - credentials are injected automatically.

### How many endpoints does the UserCheck API have?

The UserCheck API exposes 8 endpoints covering blocklist, domain, email operations.

### Can I limit what my agent is allowed to do with the UserCheck API?

Yes. Because you self-host Jentic One, your own rules decide which UserCheck operations and credentials the agent may use, so you can allow read-only checks like GET `/email/{email}` and GET `/domain/{domain}` while excluding blocklist writes such as POST /blocklist or DELETE `/blocklist/{domain}.` Since UserCheck puts the domain in the URL path (`/blocklist/{domain}`), you can pin the agent to a single domain's blocklist entry and grant only the ability to read it. Destructive operations like removing a domain from the blocklist stay off unless you explicitly add them to what the agent can call.