Werkmail vs Lettermint

Reviewed August 2026. Lettermint is a developer-first EU transactional send API: JSON from / to / subject / html, project_id as the workspace, and a thin REST surface. Werkmail is an operator platform: the same consent and content gate on GUI and API, isolated tenants, stream split, and practice kinds.

If you already have a Lettermint client, point it at Werkmail’s Lettermint drop-in (/api/compat/lettermint). Bodies stay familiar. Gates do not turn off.

At a glance

	Lettermint	Werkmail
Primary job	Thin EU transactional API	Regulated transactional + modest broadcast
DX	REST send, `project_id`, familiar JSON	HTTP JSON, curl, OpenAPI, inbound send hook
Drop-in	Native Lettermint paths	`/api/compat/lettermint` plus native `/api/emails`
Tracking	Product default	Off by default for `termin` / `recall` / `doi`
Broadcast	Not the identity	Separate `broadcast` route, DOI, Impressum
Healthcare	Generic transactional	First-class kinds + compliance check
Volume	Developer signup; verify current pricing on their site	Test → Supporter → Termin / Praxis / Gruppe

They win

Time to first send. A small JSON body and a key is the whole product story. That is a real advantage when you only need receipts or password resets.
Familiar contract. project_id, /send, /emails, and batch are what many EU apps already speak. Werkmail implements that shape; Lettermint is that shape.
Focus. They do not pretend to be a practice cockpit, consent ledger, or marketing suite.

Werkmail wins

Productized compliance. DOI ledger, channel prefs, DSAR, Impressum, List-Unsubscribe on every send including transactional.
Stream purity and practice kinds. Appointment mail cannot share a marketing pool. termin / recall / doi carry tracking and footer rules.
Same gate on GUI and API. Pointing a Lettermint client at Werkmail still hits content score, consent, suppressions, and inbox-risk pause.
Operator cockpit. DNS wizard, bounce-reason rollup, content-score history, audit CSV.

Honest gaps on our side

We will lose bake-offs that score official SDKs, SMTP, and cents per thousand.
The drop-in is a transport swap, not a clone of their dashboard or every bulk template feature. Templated bulk on Werkmail is POST /api/emails/send-bulk.
If all you need is “send this receipt from Europe,” a thin Lettermint account is rational.

Stay on Lettermint if

Your app is transactional-only, legal is satisfied by an EU vendor + DPA, and you already store consent in your own product.

Switch to Werkmail if

Someone will ask for evidence (who consented, which wording, which channel), or appointment mail must not share a pool with a newsletter — and you do not want to staff that platform yourself.

If you migrate

Keep the Lettermint client. Change the base URL to https://werkmail.eu/api/compat/lettermint and put a Werkmail bearer (wm_team_… / wm_proj_…) in the token field. Set message_kind and routes when you can. Broadcast still needs DOI and Impressum. Import suppressions; do not assume their list is yours. Details: Drop-in send APIs.