Resend vs Mailgun for inbound email to webhook (parsing + attachments)

Choosing between Resend and Mailgun for inbound email to webhook handling—especially when you care about parsing reliability and attachments—comes down to balancing simplicity, ecosystem fit, and how much control you need. Both can receive emails, parse them, and send the structured payload to your API, but they differ significantly in developer experience, pricing, and maturity of inbound features.

This guide breaks down how Resend and Mailgun compare for inbound email → webhook workflows, focusing specifically on parsing, attachments, reliability, and implementation details.

Core use case: inbound email → webhook with parsing + attachments

For most teams evaluating “Resend vs Mailgun for inbound email to webhook (parsing + attachments)”, the requirements are roughly:

Accept emails at one or more custom domains (e.g., support@yourapp.com, replies@yourapp.com)
Parse:
- From, To, Cc, Bcc
- Subject
- Plain text and HTML body
- Attachments (files, content type, size, filenames)
- Message-ID, In-Reply-To, and References (for threading)
Forward all of that to a webhook as JSON (or form-encoded)
Handle edge cases:
- Large attachments
- Multiple attachments
- Replies (quote-stripping / plaintext extraction)
- Non-UTF-8 encodings
Provide reasonable rate limits and reliability

With that in mind, let’s look at how each provider performs.

High-level comparison: Resend vs Mailgun for inbound email

Resend: modern DX, still maturing on inbound

Resend is designed primarily for developers sending transactional emails via APIs, with a very clean DX and strong TypeScript/Node ecosystem. Inbound email is supported, but it is not as battle-tested or feature-rich as Mailgun’s older inbound platform.

Pros for inbound parsing + attachments:

Simple, modern API and webhook format
Designed with modern stacks (Node, Next.js, etc.) in mind
Nice developer experience: docs, SDKs, examples
Structured JSON webhook events
Good fit if you’re already using Resend for outbound

Cons:

Inbound is newer and less battle-tested at massive scale
Fewer advanced inbound features (e.g., no decades-old ecosystem of edge-case handling)
Fewer knobs for low-level MIME quirks compared to Mailgun

Mailgun: mature, reliable, feature-rich inbound platform

Mailgun has handled inbound email for years and is widely used for parsing complex emails, routing, and forwarding to HTTP webhooks. It’s a mature system with many quirks ironed out.

Pros for inbound parsing + attachments:

Very mature inbound & parsing system
Handles complex MIME emails and encodings well
Flexible routing rules (wildcard routes, filters, etc.)
Rich webhook payloads including attachments as files or URLs
Good tooling around logs and troubleshooting

Cons:

Developer experience can feel more “legacy” compared to Resend
Settings and routing rules have more complexity
Inconsistent modern SDK support compared to Resend’s polished libraries

Inbound email setup and routing

Domain setup (both providers)

For both Resend and Mailgun, you’ll need to:

Add your domain (e.g., yourapp.com) or subdomain (e.g., mail.yourapp.com)
Verify DNS ownership
Point MX records to the provider so they can receive inbound mail

Where they differ is how you declare what to do with inbound messages.

Resend inbound routing

Resend’s approach is typically:

Configure inbound via their dashboard or API
Set up routing to a webhook or handler endpoint
Use its structured JSON event for incoming messages

For many apps, you can define a catch-all inbound destination (e.g., all emails to @inbound.yourapp.com go to a single webhook) and perform routing logic in your code, based on the “To” address.

Pros:

Simple mental model: “All inbound → my webhook → I decide”
Easier to manage in code when you have multiple mailboxes

Trade-off:

Less built-in routing flexibility; you may do more logic in your backend

Mailgun inbound routing

Mailgun uses Routes:

Define routing rules with patterns:
- Match recipient (e.g., to: support@yourapp.com)
- Wildcards (e.g., to: %support@yourapp.com)
- Catch-all rules (e.g., match_recipient(".*@replies.yourapp.com"))
Choose actions:
- forward("https://yourapp.com/webhooks/mailgun")
- store() (and later fetch)
- stop() to stop processing

This is powerful when you need:

Multiple mailboxes with different webhooks or logic
Splitting traffic (support vs billing vs replies)
Fine-grained control at the email-routing level

Parsing: headers, body, and threading

Header parsing

Both Resend and Mailgun provide the standard headers:

From, To, Cc, Bcc
Subject
Date
Message-ID
In-Reply-To / References

For a typical “reply-to-email” feature:

Mailgun: well-known to reliably expose In-Reply-To and References for conversation threading.
Resend: provides headers in a structured form, but you’ll want to confirm in their docs how all headers are exposed in inbound events for your stack.

If your primary need is consistent access to Message-ID and In-Reply-To across providers, both will handle this, but Mailgun has a longer track record with weird clients and unusual encodings.

Body parsing: plain text and HTML

Both providers parse:

Plain text body
HTML body
Some representation of stripped / cleaned versions

Key considerations:

Mailgun:
- Provides body-plain and stripped-text (quoted replies removed, signatures often trimmed)
- Very useful for building reply-processing systems (e.g., helpdesks, ticketing)
Resend:
- Offers parsed HTML and text; exact semantics of reply-stripping can be less mature than Mailgun’s long-tuned logic
- For simpler flows, this works well, but for complex quote-stripping logic you may still implement your own.

If your main requirement is “We need a clean reply body” for customer support workflows, Mailgun’s stripped-text is a strong plus. With Resend, you may need to integrate a library to strip quoted text and signatures.

Attachments handling

Handling attachments is one of the most important parts of inbound email → webhook flows. You need:

File name
MIME type
Size
A safe way to download/consume them

Mailgun attachment behavior

Mailgun offers:

Attachments delivered as multipart form-data in the webhook request
- attachment-1, attachment-2, etc.
Metadata fields (e.g., attachment-count)
Optionally you can store and fetch attachments later depending on your routing strategy.

This approach is very direct: your webhook receives files in the HTTP request itself, ready to be saved to storage like S3, GCS, or your app’s blob storage.

Benefits:

Simple processing: no second hop required to fetch files
Works well for small to medium attachments
Mature handling of multiple attachments, non-ASCII filenames, etc.

Potential drawbacks:

Large attachments mean large webhook requests
Your endpoint must handle large, potentially spiky uploads

Resend attachment behavior

Resend’s inbound webhook usually:

Includes an array of attachments with:
- Name / filename
- Content type
- Size
- Either inline data (Base64) or URLs to fetch (depending on implementation and configuration)

Exact behavior can vary as they evolve the product, but generally:

You’ll receive structured JSON describing each attachment
Often you’ll fetch attachment content or decode provided data in your own code

Benefits:

Cleanly structured JSON, easy to work with in modern frameworks
More control over when/how you download large attachments

Potential drawbacks:

Another round trip to download if attachments are not inline
Need to plan for secure and authenticated fetching if using URLs

Practical comparison for “parsing + attachments”

If your core requirement is “get the full email including attachments, immediately, in one webhook call”, Mailgun is very straightforward: everything is already in the request.

If you prefer “structured JSON + modern patterns (potentially fetching files on demand)”, Resend is more aligned with that model.

Performance, scale, and reliability

Mailgun

Long history handling very high volumes of inbound email
Designed to cope with:
- Large bulk inbound (e.g., logs, automated messages)
- Many different mail clients and obscure MIME formats
Strong SLAs on higher plans and robust logging

Mailgun is often chosen when reliability and scale are top priorities for inbound mail workflows.

Resend

Newer provider, focused heavily on modern DX and sending
Inbound is reliable for typical SaaS use-cases (support, reply tracking, etc.), but you won’t find as many stories of “massive inbound scale with complex legacy email content” as you will for Mailgun.
Good fit for modern apps whose inbound email volume is moderate to high, but not “ISP-level”.

If you expect massive inbound volume, lots of international email clients, and heavy attachment usage, Mailgun’s proven track record is a compelling reason to choose it.

Developer experience and implementation

Resend DX

Strong TypeScript/JavaScript focus
Well-designed REST API and SDKs
Very friendly for frameworks like Next.js, Remix, NestJS, etc.
Webhook data fits nicely into modern backend architectures

If your stack is:

Node/TypeScript
Serverless functions (Vercel, Netlify, AWS Lambda)
Modern monorepos and tooling

Resend feels very natural.

Mailgun DX

Long-standing REST API with multiple language clients
Admin UI for routes, logs, and debugging
Docs are comprehensive but sometimes feel more “enterprise / legacy” than modern.

If your team is polyglot (Python, Ruby, PHP, etc.) or you’ve used Mailgun before, you’ll find it very workable. But it can feel heavier compared to Resend’s sleek developer experience.

Pricing considerations for inbound email

Pricing changes over time, but in most scenarios:

Mailgun:
- Charges per message, with tiers and add-ons
- Inbound is generally included within your plan’s message volume
- Attachment-heavy usage can increase resource utilization but not necessarily billable units
Resend:
- Newer pricing model; inbound may be included or limited per plan
- Free tiers are often generous enough for early-stage projects
- Pricing may be more attractive for low to moderate inbound volume

For a project focused specifically on “inbound email to webhook (parsing + attachments)” and not sending millions of outbound emails, it’s worth:

Estimating monthly inbound volume (including test / staging)
Counting average attachment size and frequency
Comparing each provider’s pricing documentation directly

Security and compliance

Both providers handle:

TLS for inbound delivery
DKIM, SPF, and DMARC support (at the domain level)
Webhook security (signatures, secret tokens, etc.)

Mailgun security

Mature webhook signing model
Logging and persistence options that may help with compliance and audits
Often selected by teams with stricter requirements simply because of its established status and certifications

Resend security

Webhook signing / verification for events
Built with modern security best practices and frameworks in mind
Good fit if your security posture is modern SaaS but not heavy enterprise/regulated sector-level

For most SaaS teams, both options are viable; Mailgun might edge ahead for specific regulated industries due to its long-standing compliance credentials.

Concrete decision scenarios

Choose Resend if:

Your stack is modern JS/TS, and you care deeply about DX and clean JSON webhooks.
You’re already using Resend for outbound and want a unified provider.
Your inbound needs are:
- Moderate volume
- Standard attachments (PDF, images, etc.)
- Straightforward reply parsing, and you’re fine adding your own quote-stripping logic if needed.
You prefer structured JSON and possibly fetching attachments or handling Base64 content yourself.

Choose Mailgun if:

Inbound email is mission-critical for your product (helpdesk, ticketing, email-based workflows).
You need rock-solid parsing with:
- Robust quote stripping and clean stripped-text
- Many edge cases (international clients, weird MIME types)
You expect high volume or many attachments.
You want attachments delivered directly in the webhook request as multipart files.
You want powerful routing rules at the mail provider level.

Implementation tips for inbound email → webhook

Regardless of whether you choose Resend or Mailgun, you’ll want to:

Normalize inbound payloads
Build a small adapter layer in your backend that:
- Accepts provider-specific payloads
- Normalizes to your own internal structure:
  - from, to, subject
  - text, html, strippedText
  - attachments: { name, type, size, url or content }[] This makes it easier to switch providers later or support multiple providers in parallel.
Store raw message data
Save the original raw payload or provider-specific JSON/form fields for debugging:
- Helps when parsing goes wrong or you encounter unexpected formatting
- Useful for re-processing with improved logic later
Offload attachments to object storage
Immediately upload attachments to S3/GCS/Bucket storage:
- Avoid storing large blobs in your primary database
- Keep only URLs / references in your core records
Implement webhook verification
Validate provider signatures before processing:
- Prevent spoofed requests
- Protect from abuse or misconfiguration
Plan for failure and retries
- Ensure your provider can retry failed webhooks
- Make your endpoint idempotent (e.g., deduplicate by Message-ID or provider event ID)
- Log failures with enough detail to replay or reconstruct

Summary: which is better for “inbound email to webhook (parsing + attachments)”?

For the specific use case described by the slug “resend-vs-mailgun-for-inbound-email-to-webhook-parsing-attachments”:

Resend is the better choice if you prioritize:
- Modern developer experience
- Clean JSON-based webhooks
- Tight integration with a JavaScript/TypeScript stack
- Unified outbound + inbound in a modern service
Mailgun is the better choice if you prioritize:
- Ultra-reliable inbound parsing at scale
- Mature handling of complex emails and attachments
- Built-in stripped body for reply parsing
- Powerful routing and attachment delivery via multipart form-data

If inbound email (with robust parsing and attachments) is central to your product’s core value and you expect heavy, messy real-world usage, Mailgun remains the safer long-term bet. If inbound is important but not at extreme scale, and you value modern DX and simplicity, Resend is an excellent, developer-friendly option.