First-party app
NeverBounce

NeverBounce

Verify email addresses one at a time or in bulk jobs, and check credit balance, via the NeverBounce v4.2 API.

stable EmailMarketing

About

NeverBounce ships in the w6w first-party pack. It declares 10 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.

App id
io.w6w.neverbounce
Version
0.1.0
Author
w6w
Licence
MIT
Categories
Email · Marketing

Overview

NeverBounce verifies email addresses — checking a single address synchronously, or running a bulk job against thousands of rows supplied directly or fetched from a remote CSV URL. A single-check result reports one of valid, invalid, disposable, catchall, or unknown, plus diagnostic flags (DNS/MX presence, SMTP connectability, role-account and free-email detection) and an optional address breakdown.

Bulk verification is a four-step lifecycle this app exposes as separate actions so a workflow can pause between them (or react to a callback instead of polling): create a job, parse it, start it, then poll its status or read paginated per-row results — or download the whole thing as a CSV. Jobs and their results can also be searched and deleted.

Beyond verification, this app covers account visibility: a credit-balance and job-count read, surfaced both as a standalone action and as this app’s quota health check.

A fit for gating a signup flow on a real-looking address, cleaning a list before a bulk send, or scoring an existing list’s quality before importing it into a CRM or ESP.

NeverBounce’s client-side JS verification widget and its /poe/confirm server-side confirmation endpoint are deliberately out of scope — see the README.

Build with NeverBounce

Three routes to the same 10 actions. The Workflow tab is generated from NeverBounce's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.

Get Account Info

account-info

Check the account's remaining credits and job counts.

Create Job

jobs-create

Create a bulk email verification job from a remote CSV URL or supplied rows.

Delete Job

jobs-delete

Permanently delete a bulk verification job and its results.

Download Job Results

jobs-download

Download a job's verification results as a CSV file.

Parse Job

jobs-parse

Begin parsing a job that wasn't created with Auto-Parse.

Get Job Results

jobs-results

Read per-row verification results for a job, one page at a time.

Search Jobs

jobs-search

List and filter bulk verification jobs on the account.

Start Job

jobs-start

Begin processing a job that has already been parsed.

Get Job Status

jobs-status

Check a bulk verification job's progress and result totals.

Verify Email

single-check

Check a single email address's deliverability.

A workflow step names the app and the action, and the editor fills in the connection when you pick one. This is the Step shape from the workflow spec, carrying NeverBounce's real ids.

{
  "manifestVersion": "2",
  "name": "neverbounce-example",
  "steps": [
    {
      "id": "jobs-create",
      "uses": {
        "app": "io.w6w.neverbounce",
        "action": "jobs-create",
        "connection": "conn_YOUR_CONNECTION_ID"
      },
      "with": {
        "inputLocation": "<inputLocation>"
      }
    }
  ]
}

Here are some of the things you can do

  • Create Job

    perform
    jobs-create
  • Get Account Info

    read
    account-info
  • Download Job Results

    read
    jobs-download
  • Parse Job

    perform
    jobs-parse
  • Get Job Results

    read
    jobs-results

+5 more actions available

Every app-specific value here is a blank you have to fill in. An app action is reached through the connection that authenticates it, so the address is a connection id, not the app id — and connections belong to your account, so a public page cannot know yours. Create one for NeverBounce, then fill in the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the parameters that action declares. The call itself is real — the shape is transcribed from the studio's own snippet builder, which prints the same kind of blanks — but nothing in it is specific to NeverBounce. The Workflow tab is where this app's real ids are.

Install
npm install @w6w/sdk
yarn add @w6w/sdk
pnpm add @w6w/sdk
deno add npm:@w6w/sdk
Code
import { W6wClient, isActionRun } from "@w6w/sdk";

// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();

const envelope = await client.run({
  urn: "conn_YOUR_CONNECTION_ID",
  action: "jobs-create",
  payload: {
    inputLocation: "<value>",
    // remoteUrl: "<value>",
    // emails: "<value>",
    // names: "<value>",
    // ids: "<value>",
    // filename: "<value>",
    // autoParse: "<value>",
    // autoStart: "<value>",
    // runSample: "<value>",
    // allowManualReview: "<value>",
    // leverageHistoricalData: "<value>",
    // callbackUrl: "<value>",
  },
});

if (isActionRun(envelope)) console.log(envelope.value);
Install the CLI
npm install -g @w6w/cli
CLI
w6w run conn_YOUR_CONNECTION_ID --action jobs-create --payload '{"inputLocation":"<value>"}'

Give an AI agent NeverBounce — without giving it NeverBounce's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.

One tool call
{
  "name": "w6w_invoke",
  "arguments": {
    "ref": "app:io.w6w.neverbounce#jobs-create",
    "input": {
      "inputLocation": "<inputLocation>"
    }
  }
}

Every tool names its target with a single ref. The app: form above doesn't name a connection at all — the host resolves which of the caller's NeverBounce connections to sign with, and refuses rather than guesses when the answer is ambiguous.

What the agent gets

Credentials it can't read

The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.

A tool surface scoped to the caller

Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.

A durable workflow in one call

Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.

Health-aware discovery

NeverBounce's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.

The MCP surface is part of the hosted platform. NeverBounce itself is MIT, and the runtime that executes it is source-available (FSL).

Request MCP access

Health checks

NeverBounce declares its own checks, so its health is a property of the app rather than something the host guesses at.

service

NeverBounce platform status

Atlassian Statuspage rollup for status.zoominfo.com, scoped to the "NeverBounce" component among ZoomInfo's shared page. Unauthenticated and unsigned.

quota

Verification credit balance

Remaining paid + free verification credits, read from GET /account/info.