Agent skill · software engineering · sickn33
mailtrap-testing-with-sandbox
Capture outbound email in Mailtrap Email Sandbox for development, staging, CI, HTML inspection, spam checks, and fake inbox tests.
Why this skill is useful
Provides specific API and SMTP configurations for Mailtrap's sandbox environment that the AI wouldn't reliably generate on its own.
What it needs
Requires mailtrap account access. About 3k tokens when loaded. Last updated 2026-08-07. 44,571 stars on the source repository.
What this skill does
Testing with Mailtrap Email Sandbox Overview Email Sandbox captures mail in sandboxes (test inboxes)—a test environment where messages are not delivered to real recipients. You can send to sandboxes using our SDKs, HTTP API, or SMTP, depending on your needs. Before generating SDK code: read the README of the relevant SDK repository (see mailtrap-sending-emails) for current sandbox mode options, inbox id, and constructor flags. Do not rely on memory. Related skills: mailtrap-sending-emails (live sending hosts and streams). When to use You want no real delivery: dev, staging, CI, or demos where mail must stay in a test inbox. You need to inspect what was sent: bodies, headers, attachments, or basic checks (e.g. spam report) via Sandbox / Testing API or the UI. You are automating tests against captured mail. You will only change SMTP settings so an existing app sends into a sandbox—no need for a framework-by-framework tutorial from this skill. When not to use Live sends to real recipients (mailtrap-sending-emails). For full framework setup guides or detailed API references, link users to Mailtrap's Integration tab for SMTP/API details and the API docs for specifics—don't cover every framework or API field here. Quick reference API base Service Send mail URL Auth header examples ------------------------ ----------------------------------------------------- ------------------------------------------------- Email Testing API (REST) https://sandbox.api.mailtrap.io/api/send/{inboxid} Authorization: Bearer $MAILTRAPSANDBOXAPITOKEN Tokens and accountid Sandbox uses a separate token ($MAILTRAPSANDBOXAPITOKEN, Testing/Sandbox scope) — never reuse the live $MAILTRAPAPITOKEN. The accountid in the example endpoints below is resolved at runtime via GET https://mailtrap.io/api/accounts. Store tokens in environment variables or a secrets manager. When to use API vs SMTP Use SMTP when testing apps that already send mail via SMTP (just update the host, port, and credentials). …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills sickn33/mailtrap-testing-with-sandbox