canonical: https://jentic.com/apis/contactlint.com/contactlint # ContactLint API The ContactLint API checks whether an email address or phone number is valid and deliverable before you act on it. It validates a single email, runs batches of up to 50 addresses in one call, and verifies phone numbers, returning a structured result for each. Supporting operations report credit balance and usage, export everything stored against a key, and delete a key on request. Responses are JSON and authentication is a bearer token or an API key. ## For AI agents Validate email addresses one at a time or in batches of up to 50, and verify phone numbers, returning a deliverability result for each over a REST API. Authenticates with a bearer token or an API key in the x-api-key header. ## Scope Does not handle email sending, SMS delivery, or address geocoding. Use for email and phone validation only. ## Capabilities - Validate a single email address for deliverability and formatting - Validate up to 50 email addresses in one batch request - Verify that a phone number is valid and reachable - Check remaining credit balance and monthly usage for a key - Export every record stored against a key as JSON ## Use cases ### Agent-Driven Contact Validation An AI agent that collects or processes contact details can call ContactLint through Jentic to confirm an email or phone number is valid before it acts, rather than sending to a dead address. The agent passes the address to the validation operation and reads back a deliverability result, without the developer wiring the bearer or x-api-key auth by hand. Jentic returns the matching operation and its input schema so the agent validates inline. Example prompt: Validate the email address jane@example.com and only continue the signup if the result is deliverable ### Email List Hygiene Before a Send Marketing and outreach tools can clean a mailing list before a campaign to cut bounces and protect sender reputation. The batch validation operation accepts up to 50 addresses per call, bills per address, and counts as a single request toward the rate limit, so a tool can walk a large list in chunks and keep only deliverable addresses. Example prompt: Submit a batch of up to 50 addresses to the batch validation operation and drop any that are not deliverable ### Signup and Lead-Capture Validation A signup or lead form can check the email and phone a visitor entered at the point of capture so bad contacts never enter the database. ContactLint validates the email for deliverability and the phone number for reachability in separate calls, letting the form reject typos and disposable addresses before submission. Example prompt: Validate a submitted email and phone number and return a single pass or fail decision for the form ## Key endpoints | Method | Path | Description | | --- | --- | --- | | POST | `/v1/email/validate` | Validate a single email address | | POST | `/v1/email/validate/batch` | Validate up to 50 emails in one request | | POST | `/v1/phone/validate` | Validate a phone number | | GET | `/v1/usage` | Report usage and credit balance | | GET | `/v1/account/export` | Export everything stored for a key as JSON | | DELETE | `/v1/account` | Permanently delete a key and its data | ## Key resources - **Email Validation** — Validate a single email address or a batch of up to 50 addresses in one request. - **Phone Validation** — Verify that a phone number is valid and reachable. - **Usage and Credits** — Report the remaining credit balance and monthly usage for a key. - **Account** — Export everything stored against a key as JSON or delete the key and its data. ## 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:** 41 / 100 - **Maturity:** Foundational - **Dimensions:** - Foundational Compliance: 90 / 100 - Developer Experience & Jentic Compatibility: 59 / 100 - AI-Readiness & Agent Experience: 18 / 100 - Agent Usability: 94 / 100 - Security: 55 / 100 - AI Discoverability: 58 / 100 - **View full report:** https://jentic.com/apis/contactlint.com/contactlint/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 ``` ## Why Jentic - **Setup:** Wiring ContactLint by hand means choosing between its bearer token and x-api-key header auth, batching email lists within the 50-address limit, and handling the 402 response when a key runs out of checks. Through Jentic you install once, import ContactLint from the API Directory, store the credential once, and your agent calls it. - **Permission scoping:** ContactLint carries the email or phone number in the request body, so rules bound which operations your agent may call, not which address. Limit it to the validation operations it needs, and leave account deletion and data export out unless you add them. - **Credential handling:** Your ContactLint credential 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 phone number', and Jentic returns the matching ContactLint operation with its input schema so the agent calls the right endpoint directly. ## Related APIs - **Kickbox Email Verification API** — Verifies emails one at a time or in batches and flags disposable mailboxes. - **NeverBounce API** — Verifies single emails in real time and runs bulk verification jobs over lists. - **ZeroBounce API** — Validates single emails and reports the account's remaining credit balance. - **numverify API** — Returns country, carrier, line type, and location for a phone number. ## FAQ ### What authentication does the ContactLint API use? The ContactLint API accepts either a bearer token or an API key in the x-api-key header, per its OpenAPI spec. Through Jentic the credential is stored once, encrypted, by your own Jentic One instance and injected at call time, so it never reaches the agent's prompt or logs. ### Is there a ContactLint MCP server? You don't need to run an MCP server to give your agent the ContactLint API. Jentic connects it directly from the API Directory: import it, store your credential once, and your agent can validate emails and phone numbers straight away. ### Can I limit what my agent is allowed to do with the ContactLint API? Yes. ContactLint carries the email or phone number in the request body, so a rule bounds which operations your agent may call. Allow just the email and phone validation operations, so the agent can clean contact data but cannot delete your key or export its stored records, and every call it makes is logged. ### Can I validate a batch of emails with the ContactLint API? Yes. The batch validation operation accepts up to 50 email addresses in one request, bills per address, and counts as a single call toward your rate limit, so an agent can clean a list without making one request per address. ### What are the rate limits for the ContactLint API? The OpenAPI spec notes that a batch validation counts as a single request toward the rate limit but does not publish a numeric ceiling. Check the ContactLint documentation for the current limits on your plan. ### How do I validate an email with the ContactLint API through Jentic? Search Jentic for an intent like 'validate an email address' and it returns the ContactLint validation operation with its input schema, so your agent sends the address and reads back the deliverability result. To run it on your own infrastructure, install Jentic One from its GitHub repo.