Migrating from Postmark to Mailofly

Postmark is known for strong transactional deliverability, but developers often face limitations with strict stream separation (where mixing promotional content in transactional streams risks account suspension), premium pricing tiers, and lack of integrated AI tooling. Mailofly delivers identical sub-second deliverability with lower costs, native AI Model Context Protocol (MCP) support, and unified multi-identity routing.

Core Concept Translation

Postmark uses a unique conceptual model centered on “Servers” and “Message Streams”. Here is how those concepts map to Mailofly:

Postmark Concept	Mailofly Concept	Explanation
Server API Token	API Key (`mf_live_...`)	Unified secret key used to authenticate all API requests.
Transactional Stream	Transactional Send (`emails.send`)	Standard API email dispatch with priority routing.
Broadcast Stream	Broadcasts / Campaigns	Rich visual campaign editor and bulk sending engine.
Inbound Stream	Receiving Webhook	Inbound email parsing, forwarding, and webhook dispatch.
Server	Sending Identity (`account_key`)	Isolate different apps, brands, or environments cleanly.

1. SDK & Code Migration

Notice that Postmark uses PascalCase property keys (From, To, HtmlBody), whereas Mailofly uses standard modern conventions (from, to, html).

Node.js / TypeScript

# Remove Postmark
npm uninstall postmark

# Install Mailofly
npm install @mailofly/node

import * as postmark from "postmark";

const client = new postmark.ServerClient(process.env.POSTMARK_SERVER_TOKEN!);

const response = await client.sendEmail({
  From: "support@acme.com",
  To: "customer@example.com",
  Subject: "Your Password Reset Link",
  HtmlBody: "<p>Click here to reset your password.</p>",
  TextBody: "Click here to reset your password.",
  MessageStream: "outbound",
  Tag: "password-reset",
});

console.log("Postmark ID:", response.MessageID);

import { Mailofly } from "@mailofly/node";

const mailofly = new Mailofly({
  apiKey: process.env.MAILOFLY_API_KEY!,
});

const { id } = await mailofly.emails.send({
  from: "Acme Support <support@acme.com>",
  to: ["customer@example.com"],
  subject: "Your Password Reset Link",
  html: "<p>Click here to reset your password.</p>",
  text: "Click here to reset your password.",
  tags: [{ name: "type", value: "password-reset" }],
});

console.log("Mailofly ID:", id);

Python

from postmarker.core import PostmarkClient

postmark = PostmarkClient(server_token="POSTMARK_SERVER_TOKEN")

response = postmark.emails.send(
    From="support@acme.com",
    To="customer@example.com",
    Subject="Your invoice",
    HtmlBody="<p>Invoice attached.</p>",
)

from mailofly import Mailofly
import os

client = Mailofly(api_key=os.environ["MAILOFLY_API_KEY"])

response = client.emails.send(
    sender="Acme Support <support@acme.com>",
    to=["customer@example.com"],
    subject="Your invoice",
    html="<p>Invoice attached.</p>",
)

2. Inbound Email Processing

If you use Postmark Inbound Webhooks to process emails sent to your domain, switching to Mailofly’s Inbound Engine is straightforward:

Configure Custom Inbound Domain: In Mailofly, go to Receiving and register your inbound domain (e.g., inbound.example.com).
Add MX Records: Set your MX record to point to Mailofly’s inbound mail server:
inbound.example.com MX 10 inbound.mailofly.com
Webhook Payload Comparison:

Postmark Inbound Field	Mailofly Inbound Field	Description
`From` / `FromName`	`from`	Sender address and display name
`To`	`to`	Recipient address
`Subject`	`subject`	Email subject
`HtmlBody`	`html`	HTML body content
`TextBody`	`text`	Raw plaintext message
`Attachments`	`attachments`	Array of attachment metadata and download URLs
`Headers`	`headers`	Full parsed MIME headers

3. Suppressions & Blacklist Migration

Postmark automatically suppresses hard bounces, spam complaints, and manual unsubscribes:

In the Postmark dashboard, navigate to your server → Suppressions.
Click Export to download your suppressed recipient list as a CSV.
In Mailofly, go to Audiences > Contacts and click Import Contacts.
Upload your CSV and select Mark as Suppressed to prevent sending to any previously invalid addresses.

Migration Checklist

Add domain in Mailofly and add mailofly._domainkey DKIM record.
Add include:mailofly.com to your domain’s SPF record alongside Postmark.
Update client code from PascalCase (From, HtmlBody) to lowerCamelCase (from, html).
Export Postmark Suppressions and import them into Mailofly.
Update Inbound MX records and webhook destinations (if receiving inbound email).
Send verification test emails and confirm delivery on the Mailofly dashboard.

Knowledge Base

Migrations

API Keys

Domains

Sending

Deliverability

Testing

Tutorials

Build with AI

Account Management

Migrating from Postmark

Migrating from Postmark to Mailofly

Core Concept Translation

1. SDK & Code Migration

Node.js / TypeScript

Python

2. Inbound Email Processing

3. Suppressions & Blacklist Migration

Migration Checklist

​Migrating from Postmark to Mailofly

​Core Concept Translation

​1. SDK & Code Migration

​Node.js / TypeScript

​Python

​2. Inbound Email Processing

​3. Suppressions & Blacklist Migration

​Migration Checklist

Migrating from Postmark to Mailofly

Core Concept Translation

1. SDK & Code Migration

Node.js / TypeScript

Python

2. Inbound Email Processing

3. Suppressions & Blacklist Migration

Migration Checklist