langchain-verifly

LangChain integration for Verifly — agent-native email verification.

langchain-verifly gives any LangChain agent a single, well-described tool to check whether an email address is real and deliverable before it sends a message or accepts a signup. It wraps the Verifly verification API and returns a clean, structured verdict (deliverable / undeliverable / risky), the reason, a confidence score, and an actionable send-or-reject recommendation.

Installation

pip install -U langchain-verifly

Setup

Set your Verifly API key in the environment. You can self-onboard for a key (with free credits) at verifly.email.

export VERIFLY_API_KEY="vf_..."

Tool: VeriflyEmailVerifier

A LangChain BaseTool with both sync and async support.

from langchain_verifly import VeriflyEmailVerifier

verifier = VeriflyEmailVerifier()  # reads VERIFLY_API_KEY from the environment

verifier.invoke({"email": "lead@example.com"})

{
    "email": "lead@example.com",
    "result": "deliverable",
    "reason": "Mailbox exists",
    "confidence": 95,
    "is_valid": True,
    "recommendation": "send",
    "did_you_mean": None,
    "details": {
        "syntax_valid": True,
        "domain_exists": True,
        "mx_records": True,
        "smtp_valid": True,
        "is_disposable": False,
        "is_role_account": False,
        "is_catch_all": False,
        "is_free_provider": False,
        "provider": "example.com",
    },
}

Async works too:

await verifier.ainvoke({"email": "lead@example.com"})

You can also pass the key explicitly instead of using the environment variable:

verifier = VeriflyEmailVerifier(api_key="vf_...")

Use it in an agent

from langchain.agents import create_react_agent  # or any agent constructor
from langchain_verifly import VeriflyEmailVerifier

tools = [VeriflyEmailVerifier()]
# ... wire `tools` into your agent / model.bind_tools(tools) as usual

The agent can now verify an address on its own — for example, scrubbing a lead list, validating a user-supplied email at signup, or confirming a contact before drafting an outreach email.

Verdict fields

License

MIT