Mailgun through Squiid

What Mailgun is

Mailgun is an email service built around programmable sending and receiving. Outbound covers the usual API and SMTP paths with tagging, scheduled delivery and per-message tracking, while Routes match incoming mail against expressions and forward it to a webhook, which is how support inboxes and reply-to-comment features are usually built. Address validation checks whether an address is deliverable before you send, and analytics break down delivery by tag and domain. Logs retain message-level detail for a configurable period, and tags make it possible to compare delivery across different types of mail.

For an AI-coded app the inbound half is the differentiator. A product that lets users reply to a notification email and have the reply appear in the app needs parsed inbound mail, and building that on IMAP polling is unpleasant. Validation is the other piece that quietly pays for itself, because typo'd addresses in a signup form are a measurable share of bounces. Scheduled delivery and per-message tracking also make it usable for simple reminder features without a separate scheduler.

Why connect it through Squiid

Mailgun is on the Squiid roadmap. Once connected, sending and route management will go through https://api.squiid.io/v1/mailgun/... with Authorization: Bearer $SQUIID_API_KEY, with official libraries working by base URL swap (gateway convention). Messages, validations and plan cost will bill at Mailgun's listed price on one Squiid invoice, drawn from prepaid credits, and the sending key will stay with Squiid rather than being copied into every environment that needs to send a receipt. Inbound routes are configured per domain, so a support address can be handled separately from everything else.

• One account, one key, one bill, one dashboard. Mailgun sits beside every other service your project uses, on the same invoice and the same credit balance.
• Key custody. Squiid holds the Mailgun credentials. Your code carries SQUIID_API_KEY, so MAILGUN_API_KEY, MAILGUN_DOMAIN, MAILGUN_FROM_EMAIL never land in a repository, a preview deployment or an agent’s context.
• Metering you can see. Every call is counted per service and per day, so you know what Mailgun costs before the month ends.
• Pause on zero. When prepaid credits run out the gateway stops authorizing usage instead of running up a bill you did not fund.
• One rotation. Rotating the Squiid key cuts off every agent, worker and deployment at once, with no provider key to hunt down.

What you get

• Outbound sending by API or SMTP
• Inbound routing and parsing to webhooks
• Address validation before sending
• Per-tag analytics and detailed logs
• Mailgun list pricing, no markup

How to connect Mailgun

One variable replaces the provider credentials this service would normally need. Requests go to the gateway and the official SDKs work by pointing their base URL at it (gateway convention).

# .env
# replaces MAILGUN_API_KEY, MAILGUN_DOMAIN, MAILGUN_FROM_EMAIL
SQUIID_API_KEY=sq_live_xxxxxxxxxxxxxxxxxxxxxxxx

# every request: https://api.squiid.io/v1/mailgun/...
# header:       Authorization: Bearer $SQUIID_API_KEY

Pricing through Squiid

Mailgun charges a monthly plan fee by volume plus per-message and validation charges above it, at the provider's listed price. Squiid passes that through at par: one dollar of prepaid credit is one dollar of Mailgun usage, with no markup and no per-request margin.

Mailgun has no subscription attached on Squiid today. If a plan is required for a feature you need, it passes through at the provider’s listed price with no Squiid fee.

Squiid adds no markup to provider prices. There is a free plan at $0 a month with a 15% fee when you top up credits, Solo at $19.97 a month with a top-up fee that starts at 8% and falls to 3.5% as your spend grows, Team from $29.97 a seat a month with the same ladder one point lower, and Custom with a rate of 3% or less. Credits are prepaid, so Mailgun usage stops when the balance reaches zero rather than producing an invoice you did not fund. Auto top-up with a cap keeps production running without handing anyone an open-ended card.

If you leave

Export: the sending domain is re-verified in your own Mailgun account with the same DNS records, and templates and suppression lists are exported and re-imported. Squiid never owns your code, your schema or your domain, and the gateway speaks Mailgun's own API, so the client change is a base URL. The handover page lists what happens for every provider in the catalogue.

Works with every coding agent

Mailgun through Squiid is just an HTTP call with a bearer token, so every agentic coding tool can use it with the single key already in your environment:

• Claude Code
• Cursor
• ChatGPT
• Codex
• Grok
• Gemini CLI
• GitHub Copilot
• Windsurf
• Perplexity
• Devin
• Replit
• v0
• Lovable
• Cline

Vibe coding a feature on Mailgun usually means asking for it in plain language and letting the agent write the integration. Because the key is Squiid’s rather than the provider’s, it can do that without ever holding a credential that could be leaked, logged or committed.