Free Email API — GoodSender · Transactional & Marketing

section:nth-of-type(odd)]:bg-white/[0.018]">// STEP_01 — MARKETING EMAIL<br>Permission. Then send.<br>Marketing email starts with permission. Every recipient confirms before you can reach them — enforced at the API. Once they're in, send away. Mailbox providers reward this. So do we.

01<br>Add Recipient<br>Send a consent request to any email address. It takes ~150ms.

02<br>Confirmation<br>They click a link in a standard, high-reputation system email.

03<br>Confirmed<br>The recipient is unlocked for your API key globally.

04<br>Send Email<br>ONE HTTP CALL<br>Hit /v1/emails/send with markdown, HTML, or plain text. We render, suppress, and deliver from the high-reputation pool.

// STEP_02 — TRANSACTIONAL<br>Transactional templates just work.<br>Pick a template, pass your variables, and it's in the inbox. Transactional emails are pre-cleared — no consent workflow required.

encryptedMFA Enrollment<br>Verify a user as they turn on multi-factor authentication.

devicesNew Device<br>Alert users when their account is accessed from a new device.

loginLogin<br>Magic-link or one-click sign-in without a password.

receipt_longOrder Completed<br>Confirm a successful checkout with receipt-ready details.

pinOTP Code<br>One-time passcodes for 2FA and passwordless login.

more_horizMore coming<br>We expand the catalog over time based on what customers ask for.

// All other emails → permission required. Transactional → ship it.

// STEP_03 — ENGAGEMENT<br>The Engagement Check<br>Permission opens the door. Engagement keeps it open. We watch every signal — opens, clicks, complaints, silences — and handle list hygiene so your sender reputation only goes up.

01<br>Watch Every Signal<br>Opens, clicks, bounces, and complaints — tracked per recipient, aggregated into a live engagement score by our agents.

02<br>Re-Permission On Drift<br>Six months without engagement triggers an automatic re-permission ping. No response? They drop off your list — not your problem.

03<br>Auto-Suppress<br>WORKSPACE-WIDE<br>Unsubscribes and spam complaints are suppressed instantly across your workspace. You physically cannot send to them again. Reputation: protected.

Permission, engagement, and one HTTP call.<br>All of it lives behind a single endpoint. Pass markdown, HTML, or plain text — we handle rendering, suppression, and delivery on the shared high-reputation pool.

cURLNodePythonGoJava.NETRubyPHPRust<br>curl -X POST https://api.goodsender.com/v1/emails/send \<br>-H "Authorization: Bearer " \<br>-H "Content-Type: application/json" \<br>-d '{<br>"emails": [<br>"from": { "email": "sender@example.com", "name": "Example Sender" },<br>"to": [{ "email": "recipient@example.com" }],<br>"subject": "Hello from GoodSender",<br>"markdown_content": "## Hello from GoodSender\nYour first email is on the way."<br>}'

markdown<br>Markdown in,<br>email out<br>No template language. No rendering pipeline. Pass the model output directly — we handle the conversion to bulletproof email HTML.<br>MarkdownHTMLPlain text

# Welcome aboard<br>Thanks for signing up.<br>Here's what to expect...<br>- Feature one<br>- Feature two<br>YOUR_MARKDOWN<br>double_arrowWelcome...<br>Thanks for...

Feature one

GOOD_SENDER_CORE<br>double_arrowGmail<br>Outlook<br>Apple Mail<br>90+ MORE

INBOX_READY

// MCP — COMING SOON(Model Context Protocol)<br>Run a mailing list from the chat window.<br>Draft the next issue in your assistant, pick the audience, send. New subscribers get a consent request in the background — their first issue goes out the instant they confirm.<br>Available in:auto_awesomeClaudechatChatGPTterminalTerminalsmart_toyOpenClaw

Craft<br>Draft the next issue and preview it right inside Claude, ChatGPT, or your terminal. Refine until it looks right — no copy-pasting between tabs.

Pick<br>Send to the whole list, a segment, or a fresh batch of emails. Your agent lines up the audience in plain language.

Send<br>Ship now or schedule it via your assistant's task system. New subscribers get a consent request in the background — their issue goes out the moment they confirm.

// PROVENANCE<br>Earned, not built.

2009 — our founders built SendGrid to help developers solve the problem of emails landing in spam. The cloud infrastructure shipped. The deliverability problem didn't go away. Deliverability is earned, not built.<br>2018 — we left the space. Years later, the core problem was still there. Senders were still fighting for the inbox.<br>2025 — we built Laneful: email engineers, custom IP lanes, and AI agents that monitor traffic health for the largest senders in the world. Tailored involvement that reduces ESP costs and earns top-tier deliverability at scale.<br>Today — GoodSender is that same playbook, automated. Permission, engagement, and reputation wired into a single API for smaller teams and AI agents.

// AND_IT'S_RADICALLY_AFFORDABLE<br>Earned reputation scales cheap.<br>When every recipient consented and every list is healthy, infrastructure costs collapse. We pass the savings on. 100K free / month, $1 per 100K beyond. Here's how that compares:<br>FREE TIER<br>$0<br>First 100k emails/month free — covers...