Test addresses

Addresses on sandbox.email-validation.org return a fixed answer for every reason, cost nothing and never contact a mail server. Use them to test your integration end to end: the address <reason>@sandbox.email-validation.org returns that reason, with its status and action.

Every test address

Address	Status	Reason	Action
`accepted@sandbox.email-validation.org`	`deliverable`	`accepted`	`send`
`alias@sandbox.email-validation.org`	`deliverable`	`alias`	`send`
`normalized@sandbox.email-validation.org`	`deliverable`	`normalized`	`send`
`low_engagement@sandbox.email-validation.org`	`deliverable`	`low_engagement`	`send_with_caution`
`high_engagement@sandbox.email-validation.org`	`deliverable`	`high_engagement`	`send`
`trusted_catch_all@sandbox.email-validation.org`	`deliverable`	`trusted_catch_all`	`send`
`ai_agent@sandbox.email-validation.org`	`deliverable`	`ai_agent`	`send_with_caution`
`no_mailbox@sandbox.email-validation.org`	`undeliverable`	`no_mailbox`	`remove`
`no_inbound_mail@sandbox.email-validation.org`	`undeliverable`	`no_inbound_mail`	`remove`
`invalid_syntax@sandbox.email-validation.org`	`undeliverable`	`invalid_syntax`	`remove`
`likely_typo@sandbox.email-validation.org`	`undeliverable`	`likely_typo`	`remove`
`no_dns@sandbox.email-validation.org`	`undeliverable`	`no_dns`	`remove`
`mailbox_full@sandbox.email-validation.org`	`undeliverable`	`mailbox_full`	`remove`
`unroutable@sandbox.email-validation.org`	`undeliverable`	`unroutable`	`remove`
`catch_all@sandbox.email-validation.org`	`risky`	`catch_all`	`send_with_caution`
`role_account@sandbox.email-validation.org`	`risky`	`role_account`	`send_with_caution`
`role_catch_all@sandbox.email-validation.org`	`risky`	`role_catch_all`	`send_with_caution`
`disposable@sandbox.email-validation.org`	`risky`	`disposable`	`remove`
`toxic@sandbox.email-validation.org`	`risky`	`toxic`	`remove`
`forwarding_domain@sandbox.email-validation.org`	`risky`	`forwarding_domain`	`send_with_caution`
`suppressed@sandbox.email-validation.org`	`risky`	`suppressed`	`remove`
`possible_trap@sandbox.email-validation.org`	`risky`	`possible_trap`	`remove`
`spamtrap@sandbox.email-validation.org`	`risky`	`spamtrap`	`remove`
`complainer@sandbox.email-validation.org`	`risky`	`complainer`	`remove`
`server_unavailable@sandbox.email-validation.org`	`unknown`	`server_unavailable`	`retry_later`
`temporary_error@sandbox.email-validation.org`	`unknown`	`temporary_error`	`retry_later`
`greylisted@sandbox.email-validation.org`	`unknown`	`greylisted`	`retry_later`
`anti_spam_block@sandbox.email-validation.org`	`unknown`	`anti_spam_block`	`retry_later`
`timeout@sandbox.email-validation.org`	`unknown`	`timeout`	`retry_later`
`internal_error@sandbox.email-validation.org`	`unknown`	`internal_error`	`retry_later`

What they return

The status, reason and action match the address. Other fields hold fixed placeholder data: the domain is sandbox.email-validation.org, flags such as disposable and catch_all_domain agree with the reason, and credits_used is always 0. For example, likely_typo@sandbox.email-validation.org:

{
  "email": "likely_typo@sandbox.email-validation.org",
  "status": "undeliverable",
  "reason": "likely_typo",
  "action": "remove",
  "account": "likely_typo",
  "domain": "sandbox.email-validation.org",
  "did_you_mean": "accepted@sandbox.email-validation.org",
  "free_email": false,
  "role_account": null,
  "disposable": null,
  "catch_all_domain": null,
  "mx_found": true,
  "mx_record": "mx.sandbox.email-validation.org",
  "smtp_provider": "other",
  "domain_age_days": 3650,
  "processed_at": "2026-11-02T09:30:00.000Z",
  "credits_used": 0,
  "request_id": "req_7Hq2LmX9cV4bN8tR1zK6wD"
}

Where they work

POST /v1/validate and GET /v1/validate
Bulk jobs: test addresses in a list are answered for free like malformed addresses
The MCP tools validate_email and create_bulk_job

Test addresses still need an API key that works, so they exercise your authentication handling too: a revoked key, a key without the validate scope, a key used from an origin outside its allowed origins, or the key of a suspended account is refused as for any other address (a revocation can take up to 10 seconds to reach test-address answers). To test your handling of errors such as 402 or 429, mock those answers in your own tests: the OpenAPI document has an example body for every error code.