email59 MCP server

• Registry namecom.email59/email59verified in the MCP registry

The registry name sits under email59.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

• Stateanswerschecked 2026-10-29
• Tools20
• Server calls itselfemail59
• Server version0.5.0
• Protocol version2025-06-18

On 2026-10-29 the server answered initialize and tools/list without a sign-in. First answer in 170 ms.

• Its tools do every use case we checked: send sign-up codes and password resets from an app; check whether an email address is real before saving it.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

• INITE MCP score67 of 100answers 100 · does the job 100 · definitions 93 · context 100 · connects 100 · lowered by the warning signs below
• What an agent can do with it2 of 2 use cases
• Answered100% of days7 of 7 daily checks
• Median first answer393 ms
• Space in an agent's context≈ 2,573 tokensthe definitions of all its tools (20), which an agent carries on every turn
• Tool definitionsA · 93 of 100
• Typed results0 of 20 toolsdeclared outputSchema: results come typed, read once

• Parameters without a description: in 8 of 20

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

• auth

  Sign up or sign in to email59. Pass email to have a 6-digit code emailed, then call again with email and otp to get a session key (a new email is signed up with 200 free emails a day). Or pass api_key to swap an API key for a session key…

• get_pricing

  Free daily emails (renewed every day), email credits per dollar, and the packs on sale. No sign-in needed.

• get_account

  The signed-in account: email, daily_limit, sent_today, remaining_today, credits_remaining, resets_at.

• update_account

  Set the name, company or brand (the look of every email the account sends) on the account.

• send_email

  Send one email to one recipient: transactional (receipt, code, alert) or marketing (category). It goes out as HTML in a branded template with a text part; give text, html or both. Uses 1 email of today's allowance. Many recipients at…

• send_campaign

  Send a marketing email to up to 1,000 recipients; the unsubscribe link is added for you. Invalid, role, blocked or unsubscribed recipients are skipped and cost nothing; each accepted recipient uses 1 email of today's allowance. A campaign…

• check_email

  Free deep check of an email address, no sign-in needed: format, provider username rules, disposable and role addresses, and the domain's MX, SPF, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI records. Returns a report with a score (0-99…

• check_list

  List check for a mailing list: up to 1,000 different addresses a call, as emails or the text of a CSV (the column headed email). One status each: valid, risky, role, disposable, no_mx or invalid, with a reason, plus counts per status…

• validate_email

  Check an address before sending. Verdicts: ok, invalid, no_mx, disposable, role.

• block

  Block an email address or a whole domain for this account. Sends to it are refused.

• unblock

  Remove an email address or domain from the blocklist.

• list_blocklist

  The account's blocked addresses and domains.

• add_unsubscribe

  Record an opt-out. Campaigns to that list (or every list, if list_id is empty) skip the address.

• buy_pack

  Start buying a pack (pack_5 = $5, pack_10 = $10, pack_50 = $50; each $1 adds 3,636 email credits, which don't renew and last until used, plus a purchase fee of 5% or at least $0.50 at checkout; GET /v1/pricing has the totals). Returns a…

• order_status

  Status of an order from buy_pack: pending or paid.

• create_api_key

  Create a long-lived API key (max 10 per account). It is shown only once. mode 'test' makes an e59_test_ key for staging and CI: its sends are accepted and stored, never delivered, and use no allowance.

• list_test_messages

  Emails sent with a test key (e59_test_...), newest first: accepted, stored, never delivered. Pass id for one email with its html and text (a verify_start code is in there), or to to filter by recipient.

• list_api_keys

  The account's API keys (ids and labels, never the keys themselves).

• verify_start

  Email a one-time verification code to an address (sign-up, sign-in, confirming an email). email59 makes the code, sends it, limits resends and expires it; the code is never returned to you. Returns an id. Uses 1 email of today's…

• verify_check

  Check a code from verify_start. Give to (checks the newest code sent there) or id, and code. Returns valid true or false and a status: approved, wrong_code, expired, too_many_attempts (5 wrong codes lock it), already_used, replaced or…