---
ref: tool:bouncer/verify-email-list
name: Verify a list of email addresses
company: company:bouncer
workflows: []
access: [mcp, api]
tags: [capability:verify-emails, category:data-provider, has:api, has:mcp]
docs: https://docs.usebouncer.com/api-reference/batch-sync/batch-sync
updated: 2026-10-06
---

# Verify a list of email addresses

Verifies up to 10,000 email addresses in one request and returns a result for each, with status, reason, score, toxicity and domain and account flags.

Note: Takes a JSON array of addresses, up to 10,000 per request and 100 requests a minute. Results are cached for 24 hours, so the same address is not charged twice. Costs 1 credit per address; duplicates and unknown results are free.

## Set up

Use the first option your agent supports.

### MCP (official, remote)

Add this server to your agent's MCP settings, then sign in when asked.

```json
{ "mcpServers": { "bouncer": { "url": "https://api.usebouncer.com/mcp" } } }
```

Call the MCP tool `verify_emails_sync`.

Server URL: https://api.usebouncer.com/mcp

### API (official)

- Base URL: https://api.usebouncer.com
- Endpoint: `POST /v1.1/email/verify/batch/sync`
- Auth: send the header `x-api-key: $BOUNCER_API_KEY`
- Get a key: https://app.usebouncer.com
- Docs: https://docs.usebouncer.com/quick-start

Note: Create the key in the app's API section. Batch jobs run one after another per account, so a 100,000-address batch delays the next one.

Before anything else, confirm access with the cheapest read-only call, like a list or a search. Never send or change anything to test access.

## Rules

- Ask the user before anything that sends messages, costs money, or changes data, and say how many records it touches. One approval covers a batch the user has seen.
- Never print API keys.