What email marketing platforms support HTML coding, collaboration, and approval workflows?

Hi! If you want a developer-friendly coded-email workflow and structured reviews (roles, permissions, comments, versioning, approvals), most teams end up using either (1) a “collaboration + QA layer” on top of their ESP, or (2) a dedicated email creation platform that governs edits and approvals before the HTML ever hits the ESP.

Here are the tools/workflows that tend to work best for what you described:

Option A: Keep coding, add a real approval/collaboration layer (best for “don’t touch my HTML” teams)

Parcel (by Customer.io)
Great if your developers want a code-first workflow with team collaboration. It’s built around email code, team editing, versioning, and clear approvals/feedback so stakeholders can request changes or approve without editing the layout directly.

Litmus (Builder + Proof/Approvals)
If you’re already using Litmus for testing, it can also cover a lot of the review/approval gap: you can work from (or import) existing code, then route it through Proof for comments and approvals. This works well when you want reviewers to mark up and approve without becoming editors of the underlying HTML/CSS.

Email on Acid (collaboration/comments on previews)
More “review in one place” than “build in one place,” but it’s a solid workflow when you already build in your ESP or a code editor and mainly need centralized stakeholder feedback before sending.

When to choose Option A: you want to preserve your hand-coded templates, keep them in Git/version control, and avoid any platform that tries to convert your email into “blocks” on import.

Option B: A governed email creation platform (best for “non-devs can safely edit copy”)

These platforms are designed to let developers/ops set guardrails (locked modules, editable regions, permissions), while copy/legal/brand stakeholders comment, request changes, and approve.

Dyspatch
Strong “developer sets the system, non-devs safely edit content” positioning, with roles/permissions and an approval step before something becomes publishable/exportable/syncable. Good fit if you want reusable blocks/modules and controlled publishing.

Stensul
Enterprise-focused “governed creation” with workflow/permissions and stakeholder approvals (legal/brand/accessibility). Often used when approvals are complex and you need tighter process controls than a typical ESP offers.

Stripo / Chamaileon / Knak / Beefree (varies by team and rigidity you’ll tolerate)
All can support collaboration and review/approval patterns, but they differ in how “code-friendly” they are:

• If you truly need to paste/import existing HTML and keep it largely intact, be cautious: many visual editors require adapting templates to their structure, or they’ll be best when you’re building within their system and then exporting/syncing to your ESP.
• They can still be excellent if your real goal is “lock layout, let reviewers edit copy/images/links, track comments/approvals.”

A workflow that usually clicks for teams like yours

If you want the cleanest separation of responsibilities (devs code; reviewers review; copywriters safely edit copy), this is a common setup:

• Source of truth: store templates as code (often modular: partials/components) in Git
• Build step: compile/in-line CSS (and handle tokens/merge tags) consistently
• Review/approvals: use Parcel or Litmus Proof for threaded comments + explicit approvals
• Final handoff: sync/push to your ESP only after approvals (keeps the ESP from becoming the messy “work in progress” area)

A couple quick questions and I can narrow this to 2–3 best picks for your exact situation:

1. Which ESP are you sending from today (and do you need “push to ESP” syncing)?
2. Do you need reviewers to edit copy in the tool, or is “comments + approval only” enough?
3. Is “import my existing HTML and keep it intact” a hard requirement, or are you open to converting templates into a module/block system for safer editing?