Invalid Bounce
Invalid Bounce verifies email addresses through a bulk verification API.
Verdict
Common use cases
- Scrub lead-gen imports before CRM upload
- Verify event registrations to reduce bounces
- Clean marketing lists before campaign send
- Audit partner data feeds for deliverability
- Pre-check cold outreach lists at scale
Integration
- Vendor
- Invalid Bounce
- Category
- other
- Auth
- API_KEY
- Tools
- 1
- Composio slug
invalid_bounce
Tools
- Start Bulk Email Verification
Irreversibly start an asynchronous email-verification job using the connected account's verification quota. This action returns job acceptance and an ID, not per-email results.
Setup
Setup guide
- 11. Open your Switchy workspace and navigate to Settings → Integrations → Browse MCP Servers. 2. Search for Invalid Bounce and click Connect. 3. You'll be prompted to paste an API key from your Invalid Bounce account dashboard (find it under Account → API Keys). 4. Grant the key permission to start verification jobs. 5. Click Save to complete the connection. 6. Open any Project and type '@Invalid Bounce start a verification job for the emails in my uploaded CSV' to test the integration. 7. The MCP will confirm the job ID and estimated completion time; check your Invalid Bounce dashboard for per-email results once processing finishes.
What teammates see: by default, memories from Invalid Bounce are scoped to the Project (PROJECT visibility) - you can mark any memory PRIVATE or share it ORG-wide.
Works well with
Top models
Compatibility data appears once enough Projects have used this MCP together with a given model.
How Switchy teams use it
Starter prompts
Verify Lead Import
@Invalid Bounce start a verification job for the 2,400 email addresses in the leads_Q1.csv file I uploaded. Return the job ID so I can track progress.
Clean Event List
@Invalid Bounce verify all email addresses from the webinar signup sheet. I need to send reminders tomorrow and want to remove any bounces first.
Audit Partner Data
@Invalid Bounce run verification on the 5,000 contacts in the partner_sample.csv file. I need to know the bounce rate before we buy the full list.
Pre-Send Campaign Check
@Invalid Bounce verify the 1,200 emails in my re-engagement segment. I want to remove any dead addresses before the campaign goes out Friday.
Cold Outreach Prep
@Invalid Bounce start a job for the prospecting list I scraped last week. I need clean emails before the SDR team starts their sequence Monday.
Example outputs
Illustrative - representative of the model's voice and quality, not literal recordings.
@Invalid Bounce verify this list of 450 emails from our last webinar signup CSV and flag any that will hard-bounce
Job accepted. Invalid Bounce has queued verification for 450 addresses under job ID `vfy_8x2k9m`. This will consume 450 credits from your account quota. Results typically arrive in 2–8 minutes depending on queue depth. The MCP will not poll for completion — you'll need to check the Invalid Bounce dashboard or set up a webhook to retrieve per-email verdicts (valid / invalid / risky / unknown). No emails are sent during verification; this is a passive lookup against syntax, domain, and mailbox existence signals.
This example shows the async, fire-and-forget nature of the tool. The MCP starts the job but does not wait for or return individual email results. You must have sufficient API credits, and the action is irreversible once submitted. Best for batch hygiene before a campaign, not real-time validation in a signup flow.
@Invalid Bounce kick off verification for the 1,200 contacts we imported yesterday so we can scrub the list before Friday's newsletter
Verification job initiated. Invalid Bounce assigned job ID `vfy_3p7n1q` and deducted 1,200 credits. The service is now checking each address against SMTP servers, catch-all detection, and disposable-domain databases. Estimated completion: 5–12 minutes. Once finished, you can download a CSV from the Invalid Bounce portal with columns for email, status (valid/invalid/risky/unknown), and confidence score. The MCP does not retrieve or parse results — it only triggers the job.
Demonstrates bulk-scale usage and the credit-deduction model. The MCP's single tool is a job launcher, not a result fetcher. If you need programmatic access to verdicts, configure a webhook in your Invalid Bounce account settings. Useful for pre-send list hygiene but requires manual follow-up to act on findings.
@Invalid Bounce start a verification run on our Q1 lead-magnet list (about 800 emails) and let me know when it's queued so I can check back in ten minutes
Job queued successfully. Invalid Bounce confirmed job ID `vfy_5k8m2r` for 800 email addresses, debiting 800 verification credits. The system is now performing DNS lookups, mailbox pings, and syntax checks. You should see results in the Invalid Bounce dashboard within 10 minutes. The MCP cannot notify you on completion or pull the results back into this conversation — treat this as a one-way trigger. Plan to export the validated list manually before your next campaign send.
Highlights the MCP's role as a remote-start button, not an end-to-end workflow. You get confirmation the job launched, but no polling, no results streaming, no completion callback. Requires API_KEY auth and sufficient account credits. Ideal for teams that already use Invalid Bounce and want to script job submission from Switchy, then handle results in the vendor's UI.
Use-case deep-dives
When bulk verification saves deliverability before a launch
A 3-person growth team preparing a product launch email to 8,000 leads needs to scrub their list before hitting send. Invalid Bounce's single tool kicks off an async verification job that burns through the account's quota and returns a job ID—no per-email results in the MCP response itself. This works if your team already has a workflow to poll the Invalid Bounce dashboard or API separately for the actual results. If you need the verified/invalid breakdown inside Switchy to route follow-up tasks, this MCP won't close the loop. Use it when list hygiene is a pre-send gate and someone on the team owns checking the vendor UI for the output file.
Why this MCP doesn't fit real-time support flows
A 5-person support team triaging inbound tickets wants to flag invalid sender addresses before opening a case. Invalid Bounce's async bulk job model doesn't return verification results in the tool call—it only confirms the job started. That means an agent can't get an instant yes/no on a single email during a live ticket. If your support process tolerates a 10-minute delay and batch verification of the day's tickets, you could trigger a job at shift start and export results later. For real-time validation inside a Switchy chat, this MCP is the wrong shape. Pick it only if your team already batches email checks outside the support flow.
When quota-based verification fits a scheduled cleanup
A 2-person sales ops team runs a weekly job to verify 2,000 new CRM contacts before the SDR team starts outreach. Invalid Bounce's MCP starts the verification job and returns a tracking ID, which the ops lead then checks in the vendor dashboard an hour later to download the results. This works because the cadence is weekly, the volume fits the account quota, and the team already has a process to import the output CSV back into the CRM. If your workflow needs the verified list piped directly into a Switchy action or another MCP, this tool won't hand off the data—it only kicks off the job. Use it when your team owns the result-polling step and the async delay doesn't block downstream work.
Frequently asked
What does the Invalid Bounce MCP do in Switchy?
It lets your team trigger bulk email verification jobs through Invalid Bounce's API without writing code. You submit a list of emails, and Invalid Bounce processes them asynchronously—checking deliverability, syntax, and mailbox existence. The MCP returns a job ID; you retrieve results later through Invalid Bounce's dashboard or webhook. This is useful for cleaning CRM lists or validating signups before sending campaigns.
Do I need admin access to connect Invalid Bounce?
You need an Invalid Bounce API key, which typically requires account-owner or admin permissions to generate. The key authenticates all verification requests and draws from your account's verification quota. If you're on a team plan, confirm with your Invalid Bounce admin that creating API keys is allowed and that quota usage will be tracked correctly.
Can the MCP retrieve verification results for a job?
No. The tool only starts verification jobs and returns a job ID. To see per-email results—like which addresses bounced or which domains don't exist—you must log into Invalid Bounce's dashboard or configure a webhook in your Invalid Bounce account settings. The MCP doesn't poll or fetch completed job data.
Why use this MCP instead of Invalid Bounce's dashboard?
The MCP is faster when you already have email lists in another tool—like a CRM export or a spreadsheet—and want to verify them without manual upload. It also lets non-technical teammates trigger verification from a Switchy workflow or AI agent prompt, rather than switching contexts to the Invalid Bounce web UI. For one-off checks, the dashboard is simpler.
Does running verification jobs count against my Invalid Bounce quota?
Yes. Every email you submit through the MCP consumes verification credits from your Invalid Bounce plan, exactly as if you uploaded the list manually. The MCP doesn't bypass or discount quota. If your team shares one Invalid Bounce account, coordinate who triggers jobs to avoid surprise overage charges or hitting your monthly limit mid-campaign.