Alternatives to Letterkeel: Send Email via SMTP, Resend, SendGrid & Mailgun

• Responded15 / 22 checks passed

  Formquote

  Keith-CYVerified

  Published prices and licence fit for email verification, sound effect packs and font licences.

  Developer ToolsCommunication & messaging

  • Productivity & docs

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 96 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Notify Sound

  botmonsterVerified

  Design notification sounds from layered tones and get an editor link to play and download.

  Developer ToolsCommunication & messaging

  • Design & media

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 99 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Stackhal

  bahdanhalVerified

  Outside-in DNS, email security, SEO, GEO and app-link checks plus developer utilities.

  Developer ToolsCommunication & messaging

  • Productivity & docs
  • Security & identity
  • Commerce & marketing

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 115 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Mailvett: Email Validation API for AI Agents

  CyberMax-toolsVerified

  Mailvett: validate emails. MX, provider, disposable/role/free flags, typo fix, verdict.

  Developer ToolsCommunication & messaging

  • AI models & agents
  • Productivity & docs

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 174 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Postlyra

  prof-1tVerified

  Manage Telegram drafts, media, schedules and publications from AI clients.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 176 ms · Last checked 14 hr ago

• Responded15 / 22 checks passed

  Agent Commons

  sibi-narendranVerified

  A home for any agent: inbox, public memory, job board, rooms, human help. Free, no key.

  Developer ToolsCommunication & messaging

  • AI models & agents

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 258 ms · Last checked 10 hr ago

• Responded15 / 22 checks passed

  BillionVerify

  BillionVerifyVerified

  Email verification for AI agents: verify single or bulk emails, check credits and history.

  Developer ToolsCommunication & messaging

  • AI models & agents
  • Productivity & docs

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 265 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Emailens MCP

  emailensVerified

  Analyze, audit, fix and diff HTML, MJML, Maizzle and React Email across 21 email clients.

  Developer ToolsCommunication & messaging

  • Productivity & docs

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 437 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Frasma

  francemazziVerified

  Read-only Frasma MCP: profile, knowledge search, diagnostic handoff. No email.

  Developer ToolsCommunication & messaging

  • Search & web data
  • Productivity & docs

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 519 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Ichimoku Signal

  Fizzl13Verified

  Free Ichimoku trend; paid signals, levels, scan, setups and Telegram signal alerts via x402.

  Developer ToolsCommunication & messaging

  • Finance & payments

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 803 ms · Last checked 17 hr ago

• Responded15 / 22 checks passed

  Smarter Weather

  smarterweatherVerified

  Smarter Weather MCP: forecasts, alerts, outlooks, observations, AQI, grids, and map imagery.

  Developer ToolsCommunication & messaging

  • Maps, travel & real estate

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 1010 ms · Last checked 10 hr ago

• Outdated check14 / 22 checks passed

  Formspark MCP by usefulapi

  usefulapi.ioVerified

  List forms and submissions, and create or update forms and their notifications in Formspark.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 51 ms · Last checked 1 day ago

• Outdated check14 / 22 checks passed

  Telegram MCP by usefulapi

  usefulapi.ioVerified

  Read chats and members; send, edit and delete messages with a bot in Telegram.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 60 ms · Last checked 1 day ago

• Outdated check14 / 22 checks passed

  Temp Stick MCP by usefulapi

  usefulapi.ioVerified

  Read temperature and humidity sensors, their readings and alert notifications in Temp Stick.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 67 ms · Last checked 1 day ago

• Responded14 / 22 checks passed

  Potarix Enricher

  PotarixVerified

  Find company websites and verified business emails through the Potarix Enricher API.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 96 ms · Last checked 19 hr ago

• Responded14 / 22 checks passed

  Openhook

  openhook-devVerified

  Private channels for people and their AI agents.

  Developer ToolsCommunication & messaging

  • AI models & agents

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 98 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  openradar

  MikhailSagalaevVerified

  Open base of job vacancies and freelance orders from Russian and international boards and Telegram.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 99 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  io.github.fnobbe/crashtestyourstrategy

  fnobbeVerified

  Portfolio and strategy stress diagnostics with hedge-break detection and regime outlook. Free tier.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 125 ms · Last checked 23 hr ago

• Responded14 / 22 checks passed

  RegEvidenceHub CQC

  ChanghuLiuVerified

  RegEvidenceHub CQC: England provider-registration and statutory-notification preflight.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 129 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  Domain Trust Check (DNS, Email Auth, TLS, Headers)

  pcp183Verified

  Check a domain's DNS, SPF/DMARC and TLS before trusting it. $0.003/call via x402.

  Developer ToolsCommunication & messaging

  • Finance & payments
  • Productivity & docs
  • Cloud & infrastructure

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 142 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  Fieldwright

  CyberMax-toolsVerified

  Fieldwright: web page to clean Markdown, metadata, JSON-LD, emails, phones.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 142 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  DreamAgent

  nivethaugVerified

  Build and deploy websites, Telegram and Discord bots from chat via the DreamAgent platform.

  Developer ToolsCommunication & messaging

  • Communication & social

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 143 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  Email Address Check (syntax, MX, disposable, SPF/DMARC)

  pcp183Verified

  Check email addresses for syntax, MX and disposable domains. $0.0015/call via x402.

  Developer ToolsCommunication & messaging

  • Finance & payments
  • Productivity & docs

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 171 ms · Last checked 17 hr ago

• Responded14 / 22 checks passed

  Dataset Cleaner & Exporter

  Nero-EngineVerified

  Dedupe, flatten and clean messy JSON rows (emails, phones, URLs, HTML) in one call, as JSON or CSV.

  Developer ToolsCommunication & messaging

  • Passed: Handshake
  • Passed: Tools listed
  • Passed: Updated recently

  Median latency 176 ms · Last checked 17 hr ago

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