Zammad's means run higher on ticketing core (6.0 to 1.0), omnichannel (6.8 to 0.3), knowledge and self-service (4.2 to 0.2), integrations (4.0 to 0.0), sovereignty (6.3 to 3.5) and pricing transparency (6.8 to 0.0); OTRS publishes no prices, and pricing was not weighted against it. The split: customer data protection (3.8 to 2.8), one judge leaning OTRS, five lean Zammad. OTRS's case there is legal posture — German contracting entity, named external data protection officer, stated retention periods — scored 2–4 on the credit those practices earn; Zammad's captures show no tenant DPA, retention period or audit log evidenced. OTRS's other scores rest on legal pages where we found no public information on queues, routing, SLAs, APIs or connectors. Weighted totals per judge run Zammad 5.3–5.6 against OTRS 0.5–2.2. Zammad's gaps: only GitHub/GitLab and Grafana/Elasticsearch named as integrations; telephony appears in no tier's channel list and carries no price.
Choose OTRS if
Your contract must sit with a German-registered vendor — OTRS's legal entity jurisdiction is DE, and the imprint names OTRS GmbH, Oberursel (Amtsgericht Frankfurt am Main HRB 143059, VAT DE453344897).
You need a named external data protection officer documented before signature — OTRS's privacy-policy captures show one.
Your compliance gate is stated retention periods in a published privacy policy — OTRS's captures state them.
Your reviewers credit data-protection practices evidenced on the vendor's own site — on customer data protection, where OTRS scores spread 2–4, one judge leaned OTRS.
Choose Zammad if
You need core ticketing evidenced — states, assignment, escalations, SLAs, macros, templates and automation rules are named in Zammad's captures; ticketing core means 6.0 to 1.0, with 6 judges leaning Zammad.
Your customers reach you on many channels — email, web form, SMS, chat, Telegram, Facebook and WhatsApp are priced per tier into a unified ticket view (omnichannel 6.8 to 0.3).
You must budget before pilot — Zammad publishes €7/€16/€25 per agent per month plus a metered €0.03 per AI call, with VAT treatment stated (pricing transparency 6.8).
Your residency requirement is EU-only — Zammad's data residency attribute reads EU only and its subprocessor exposure reads none.
You want the self-hosted option — Zammad is offered cloud or self-hosted, and its sovereignty scores of 6–7 credit that option (sovereignty means 6.3 to 3.5).
Read this comparison as one judge. Each weighs the same scores by what they care about.
The Data Protection Officer
Sees a ticket archive for what it is: years of personal data customers typed themselves, including the things they should not have. Wants retention that executes, redaction, an audit of who read what, and an answer on whether vendor support can open a ticket.
OTRS
Zammad
This judge's pick
Criterion by criterion
Ticketing, queues & SLA
OTRS
Not one fact about routing, queues, SLA timers, escalation or search appears in any capture; a 'Customer Service & Helpdesk' category label and a homepage are all I have, and a label is not an engine. Absence this total sits at the bottom of the scale, with a single point only for the category claim.
Zammad
States, assignment, escalations, macros, templates, automation rules, SLAs and reporting are all evidenced, which clears the mid anchor. But nothing on business-hours-aware SLA policies, escalation chains, merge/split, or full-text search across ticket bodies, so it stays below the 8.
Channels in one queue
OTRS
No chat, portal, phone, or messenger integration is evidenced anywhere in the evidence, so there is nothing to credit beyond the helpdesk category's implied email handling — which is the anchor-zero position. The marketing site's own channels (forums, video, X buttons) are about OTRS, not the product's queue.
Zammad
Email, web form, chat, SMS, Telegram, WhatsApp and Facebook all land in one structured ticket view with shared history, plus telephony integration. Deducted because messenger consent handling is not stated, there is no evidenced customer portal where a requester sees their own tickets, and call logging is a bare phrase.
Knowledge base & deflection
OTRS
The only knowledge-adjacent fact is that OTRS's own website shows FAQs to registered visitors — a vendor article list, not a product help centre, editorial workflow, or deflection reporting. Nothing here evidences the product organising or reducing ticket volume.
Zammad
A help centre and a knowledge base exist, multilingual on the Plus tier, with the stated aim of customers solving issues without a ticket. No editorial workflow, no versioning, no suggestions to agent or customer, and no deflection reporting are evidenced, so this sits between the basic article list and the working public help centre.
Customer data protection
OTRS
The vendor polices its own house well — named external DPO (IITR), published privacy statement, Trust Center, and concrete retention per data category (6-month application data, 3-year trial, 10-year email archive) — but says not one word about the product: no queue-level retention rules that execute, no redaction, no audit of who opened which ticket, no DPA, no answer on vendor support access, and a blanket 'usually 10 years' is a hoard, not a policy. That is a compliance posture, not capability, and it sits between rubric level 0 and 3.
Zammad
GDPR rights including deletion are listed and configurable roles/permissions and 2FA exist — but the deletion clause is the vendor's own website-inquiry auto-delete, not a path for a customer's ticket archive. No published DPA, no stated retention period for ticket data, no audit log of who opened which ticket, no redaction, no attachment-handling policy, and total silence on whether Zammad support can open a hosted instance's tickets.
Integrations & API
OTRS
No API, webhook, SSO, rate limit, or named integration appears in any captured page; context would have to be copied in by hand, which is precisely the zero anchor. Across three homepage captures not a single system-to-system fact surfaced.
Zammad
Open APIs and ready-to-use integrations are claimed, with named GitHub/GitLab and Grafana/Elasticsearch integrations. But no CRM, shop or identity integration is named, and there is no evidence of webhooks, SSO, rate limits, bidirectional sync or a sandbox — a read-mostly API with a few connectors.
European sovereignty
OTRS
The contracting entity is firmly German — OTRS GmbH, Oberursel, HRB 143059 at Amtsgericht Frankfurt, DE VAT — and the privacy policy does name subprocessors and discloses third-country transfers with SCCs for the US video-conferencing processor. But that subprocessor list is the marketing website's trackers (Google, LinkedIn, Vimeo, 6sense), the hosting location of a customer's ticket archive is nowhere stated, and whether OTRS support can open a customer instance goes unanswered — better than the pipeline's zero, short of anchor five.
Zammad
German contracting entity (Zammad GmbH, Berlin, commercial register Charlottenburg), German ISO27001 data centre, and crucially a self-hosted option that puts the archive on the buyer's own infrastructure. The data-centre provider is unnamed and no subprocessor list exists for the product chain — the only named subprocessors, Matomo and Moosend, serve the vendor's website.
Pricing transparency
OTRS
No price, tier, add-on, billing period or agent-count fact appears in any capture; a support lead could not compute even a rough invoice from this evidence, which is the bottom anchor.
Zammad
All three tiers carry public per-agent prices with agent limits, channels, storage, support hours, VAT treatment and a metered AI fee of €0.03 per call — nearly computable. Billing period and minimum term are unstated, and telephony appears on the product page but in no tier's channel list, so its price position is a guess.
Sovereignty, side by side
Dimension
OTRS
Zammad
Legal entity
Incorporated in DE
Incorporated in DE
Ownership
Not determined
Not determined
Data residency
Not determined
EU only
Subprocessors
Not determined
Not determined
Facts, side by side
Only facts both products carry under the same definition — anything else would not be a fair row.