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Fully Managed LanguageTool
as a Service

Deploy LanguageTool as a fully managed service starting at €9/mo. Get automated backups, SSL, updates, support and monitoring included.

LanguageTool is an open-source grammar, style and spell checker for 31+ languages — combining the convenience of Grammarly with the security and control of self-hosted infrastructure. Used in newsrooms, law firms, and writing centres worldwide.

Free 7-day trial  99.9% Uptime SLA  No credit card  Cancel anytime

Free 7-day trial  99.9% Uptime SLA
No credit card  Cancel anytime

LanguageTool

LanguageTool

STARTING AT

€9/month
Automated Backups
Monitoring
Automated Updates
Auto SSL

USAGE

Unlimited
Human Support
Custom Domains
Terminal Access
File Manager Access
Deploy in your region 21 locations worldwide
GermanyFinlandNetherlandsUKSwedenUnited StatesCanadaSingaporeJapanAustraliaBrazilSouth Africa+9 more →
LanguageTool Preview Image

ABOUT THE SOFTWARE

What is LanguageTool

LanguageTool is an open-source proof-reading service for grammar, style, spelling, and confusion errors across 31+ languages. The core is LGPL-2.1, maintained by LanguageTooler GmbH and a community of language-specific volunteers. It runs as a Java server you call from browser extensions, office suites, editors, and CI pipelines.

The project started in 2003 in Germany as Daniel Naber's diploma thesis. The source is at github.com/languagetool-org/languagetool and the standalone server distribution shipping as a single Java archive. The repository has 14,400+ GitHub stars and 1,500+ forks. LanguageTooler GmbH (Hamburg) handles commercial Premium; the LGPL core is fully self-hostable and used by writing-centre infrastructure, EU-funded research projects, and government-adjacent communications offices.

Memory and disk footprint depend entirely on whether you load the n-gram confusion-pair data: a minimal grammar-only server runs in 512 MB of heap, while the English n-gram archive alone unpacks to roughly 14 GB on disk and benefits from 4 GB of JVM heap. The same single binary serves grammar checking over a documented REST API — /v2/check is the workhorse endpoint — to browser extensions, LibreOffice 7.4+'s built-in remote grammar checker, the official WordPress plugin, the LTeX+ Language Server for VS Code, Obsidian, Vim, Emacs, and any custom integration via HTTP.

FEATURES

What LanguageTool does

LanguageTool checks grammar, style, typography, and confusion-pair errors across 31+ languages. It runs as a server called from browser extensions, office suites, code editors, and CI pipelines. The LGPL core supports custom dictionaries, rule disabling, picky-mode style hints, and the full REST API.

Grammar, style, and typography rules

Thousands of rule-based checks per language for grammar agreement, false friends, redundancies, and style smells. Picky mode adds tighter style suggestions; plain mode keeps only high-confidence errors.

31+ languages, one endpoint

One LanguageTool instance speaks English (US/GB/CA/AU/NZ/ZA), German (DE/AT/CH), Spanish, French, Portuguese (BR/PT), Polish, Dutch, Russian, Italian, Catalan, Romanian, Ukrainian, and 20+ others — auto-detected per request.

Custom dictionaries and rule overrides

Add brand names, medical terms, legal citations, or product names to per-language dictionaries; disable categories or specific rules through config or per-request parameters.

Markdown, HTML, LaTeX, and AnnotatedText support

Send raw text or annotated text where formatting is preserved; LanguageTool flags errors at the right offset and skips code blocks, URLs, and tags.

Confusion-pair detection via n-grams

Catches their / there, its / it's, affect / effect, and the language-specific confusion sets a spell checker misses. Available for five languages with the n-gram archives loaded.

Documented REST API at /v2/check

POST the text, receive a JSON list of matches with offset, length, suggested replacements, and rule IDs. The same API used by every official client and every third-party integration.

Browser, office, editor, and CI integrations

Works with the official Chrome/Firefox/Edge/Safari extensions (point to your endpoint), LibreOffice 7.4+'s built-in remote grammar checker, the WordPress plugin, the LTeX+ Language Server in VS Code, Obsidian, Vim, Emacs, and language-tool-python.

Java library or standalone HTTP server

Embed the JARs directly into a Java application via Maven Central, or run the standalone HTTP server. Same rule engine either way.

WHAT'S ALWAYS INCLUDED

Every app. Fully managed.
Nothing extra to pay for.

Every app you deploy includes the full managed service — security, backups, updates, and support from day one.

Automatic updates and patches

Apps run the latest stable version. Security patches applied silently, with rollback if needed.

Daily off-site backups

Multiple daily backups in redundant off-site locations. One-click restore if anything goes wrong.

24/7 uptime monitoring

Continuous monitoring with instant alerting. We respond before you notice.

SSL, firewall, DDoS protection

Auto-renewing SSL, hardened firewall rules, DDoS mitigation on every deployment.

Performance and scaling

We monitor resource usage continuously. When your app needs more headroom, we flag it and upgrade with your explicit approval.

Dedicated engineering support

Real engineers on chat. DNS, SMTP & migration help. All included in €9.

WHY MANAGED

Why teams pick managed LanguageTool

On 19 December 2024, LanguageTool moved its data controller from Germany to Learneo, Inc. in California. For teams that picked LanguageTool as the European alternative to Grammarly — under EU data-protection rules and Schrems II — the hosted endpoint stopped being European overnight. Self-hosting the LGPL core became the only way to keep that promise.

Just running LanguageTool is not the same as running it well. The default Docker images ship with a 512 MB JVM heap and a cold-start grammar pipeline; the first request on a fresh container can take eight seconds. The embedded HTTP server does not speak HTTPS, so the official browser extensions — which require HTTPS to a self-hosted backend — will not connect until a TLS-terminating reverse proxy sits in front. The n-gram confusion-pair data that catches their / there and brakes / breaks errors is a one-time download from the project's website — but at 8.35 GB compressed and roughly 14.3 GB unpacked for English alone, it is a multi-gigabyte storage decision before a single sentence is spell-checked.

REVIEWS

Hear from customers ​like you​​​​​​​

Successful businesses and professionals around the world rely on DANIAN every day

USE CASES

Three teams who run LanguageTool on DANIAN

These are representative team types we set up most often. Each starts with the same flat €9 plan.

6-PERSON LEGAL-TRANSLATION BOUTIQUE

Translating German contracts after Schrems II

Munich-based. Germany region. English, German, and French n-grams preloaded; 200,000-character text-length ceiling for long patent filings. Translators draft in LibreOffice with the built-in remote grammar checker pointed at their DANIAN endpoint; partners review in Word via the browser-extension proxy.

8-EDITOR WORDPRESS CONTENT AGENCY

One LanguageTool endpoint for 14 client sites

Lisbon-based. France region. Editors run the official WordPress plugin on every client site and proofread final copy in LibreOffice. Pipeline prewarming kills the 8-second first-request lag they hit on the public API. Portuguese and English n-grams preloaded.

12-PERSON INVESTIGATIVE NEWSROOM

No US SaaS in the drafting pipeline

Brussels-based. Netherlands region. Reporters draft in Obsidian and VS Code (LTeX+ Language Server); editors review in WordPress. Editorial policy forbids drafts touching US-hosted services. Self-hosted LanguageTool replaced Grammarly Pro for the whole desk — €9/mo flat against $180/mo per-seat.

COMPARISON

Four ways to run LanguageTool

The buyer's choice is rarely between hosting services. It's between paying Grammarly per-seat forever, running it yourself on a virtual server, running it at home, or letting someone else operate it. The math at every team size points the same way.

 PATH1 USER5 USERS 10 USERSWHAT YOU TRADE
Grammarly Pro / Pro for teams
$12/mo$75/mo$150/moPer-seat pricing; data processed by Grammarly in the US; six languages; AI features bundled in whether the team wants them or not.
Self-host on a $24/mo production-class VPS
$44+/mo + ops time$44+/mo + more ops$44–$88/mo + significant opsBuy and pay a sysadmin to tune the JVM, manage the TLS reverse proxy, stage the n-gram archive, and verify backups every month.
Home server on a Synology DS923+ NAS
~€100/mo~€110/mo~€130/moOne-time €650 hardware; business internet with static IP; off-site backup target; 2–4 hours per month of ops work.
DANIAN Managed LanguageTool€9/mo€9/mo€9/moFlat per-instance pricing regardless of users. No JVM tuning. No reverse proxy. No 14 GB archive to manage. Human support included.

VPS path totals: $24/month for a 2 vCPU / 4 GB production-class virtual server, plus ~$5/month object-storage backup and ~$15/month monitoring = $44/month infrastructure, before 5–10 hours of setup and 1–2 hours per month of patching, certificate renewal, and backup verification at a €60–120/hour sysadmin rate.

Home-server path totals: Synology DS923+ amortised over 36 months (~€18/mo) + 80–150 W electricity at €0.30/kWh (€17–32/mo) + business internet with static IP (€40–80/mo) + off-site backup target (€10–20/mo) + 2–4 hours/month of ops time at €60–120/hour.

DANIAN's price covers the JVM tuning, the n-gram archive, the TLS reverse proxy, daily backups, updates, monitoring, and human support. Add users to your team without changing the bill.

BY INDUSTRY

LanguageTool for specific industries

A grammar checker becomes a procurement question the moment confidentiality, professional secrecy, or regulator-mandated documentation enters the picture. These five industries are where we see LanguageTool replace hosted services for reasons that have nothing to do with grammar quality.

On 19 December 2024, LanguageTool's hosted service moved its data controller to Learneo, Inc., California. For German Mittelstand law firms and translation boutiques whose professional-liability insurers explicitly ask about US sub-processors after Schrems II, that is a procurement-blocker. Member-state professional-secrecy law (German § 203 StGB, the French secret professionnel) raises the bar further: drafts of depositions, contracts, and patent filings cannot route through a US-controlled grammar API.

We run their LanguageTool instance in Germany or Netherlands with English, German, and French n-grams preloaded — about 19 GB of language-model data resident at start — and a 200,000-character text-length ceiling so long contracts check in one pass. Translators hit the endpoint from LibreOffice's built-in remote grammar checker; partners review in Word through the browser-extension proxy pattern documented in the LanguageTool forum.
Clinical-research organisations, medical-device manufacturers, and pharma communications teams write under standards their hosted-SaaS vendors are not certified to. ISO 13485 quality systems and EU MDR Regulation 2017/745 require traceable, in-region document workflows; protocol drafts and clinical study reports routinely contain patient identifiers that cannot be sent to a US-headquartered grammar checker.

We run their LanguageTool with a custom medical dictionary — drug names, anatomical terms, clinical-trial vocabulary — loaded into spelling.txt per language, typically 2,000–5,000 terms (LanguageTool's personal dictionary supports up to 25,000). Writers work in Word with a self-hosted-LT-routing browser extension; a 15-author medical-writing CRO producing 40 documents per month at 30k words processes everything in-region with no patient data leaving the network. The custom dictionary is version-controlled in their existing git so terminology updates are reviewable.
Newsrooms drafting on confidential sources, leaked documents, and pending legal cases run editorial policies that ban US SaaS for drafts. EU Directive 2019/1937 (whistleblower protection) and member-state press-shield laws (German §§ 53/97 StPO; equivalent provisions across most EU states) make source protection a procedural requirement, not a vibe.

We host LanguageTool in the customer's chosen region with rate limiting tuned for the newsroom workflow (about 80 requests per minute per IP) so a stuck linter cannot saturate the queue. Reporters draft in Obsidian with a community LanguageTool plugin; longform editors use VS Code with the LTeX+ Language Server; copy desk finishes in WordPress. One endpoint, three clients. A 12-editor newsroom producing roughly 250 articles a month sees warm-pipeline latency under 300 ms versus the 8,880 ms cold start on a vanilla container.
Language service providers running ISO 17100-compliant translation workflows need a grammar checker their CAT tools can call, with custom rule sets per client. LanguageTool's REST API plugs into memoQ, Trados, OmegaT, and Wordfast via small custom hooks; per-language confusion_sets.txt extensions let an LSP encode client-specific homophone pairs (brand-name disambiguations, regulated-product nomenclature).

We host with cacheSize="1000" and a 4 GB heap so a translator confirming segments does not wait between sentences. A mid-size LSP processing 200,000–500,000 words a week across 8–12 languages runs through one DANIAN instance comfortably on 4 vCPU; an upgrade path is one ticket away. ISO 18587 post-editing of machine translation gets a second grammar pass without sending segments to a hosted endpoint the LSP cannot audit.
Government communications teams writing in the EU under the AI Act (Regulation 2024/1689 in force since 2 August 2025) and the NIS2 essential-entity rules prefer rule-based, non-generative checking for citizen-facing drafts: deterministic, reviewable, no opaque model behind the suggestions. LanguageTool's core is rule-based — no LLM in the path — which makes the AI Act conversation shorter.

We deploy in sovereign-cloud regions where the customer requires it, disable fastText auto-language-detection if the agency wants deterministic single-language behaviour, and enable only the languages the office actually publishes. A municipal communications office of 25 staff drafting roughly 400 citizen letters a week in two or three languages runs comfortably; civil servants get inline checks in LibreOffice (still the default office suite in many EU public administrations) without text leaving the agency network.

FAQ

Frequently asked questions

Everything teams ask before signing up — answered straight, without sales speak.

Three groups: technical setup, migration, and how DANIAN works as a service.

01

Technical and configuration

Works: the official Chrome, Firefox, Edge, and Safari extensions (configured for "Other server"), LibreOffice 7.4+'s built-in remote grammar checker, the official WordPress plugin, the LTeX+ Language Server in VS Code, the language-tool-python library, plus Obsidian, Vim, Emacs, and CLI usage. Does not work with a self-hosted endpoint: the official MS Word add-in and the official LanguageTool desktop apps — both are locked to the hosted endpoint.
A correctly configured self-hosted LanguageTool does not. The only optional outbound calls are a one-time fastText language-model download and the hosted A/B test endpoints — both disabled in our default configuration. The text stays on the server in the region you picked.

02

Migration and onboarding

We can activate your app on your own custom domain/subdomain. Examples: mydomain.com, anyword.mydomain.com.
Or, on our randomized free subdomain. Example: 963.apps.danian.cloud
If you wish to use a custom domain/subdomain, select that option when ordering your app (or notify us later). We will send you the required DNS records and if needed, our tech team will modify them for you.
21 datacenter locations across six continents. You choose the region at provisioning. Application data sits in the region you choose; pick whichever is closest to your users or matches your data-residency preference.
Yes. Request a region migration from the dashboard and we run the move in the background. The system emails you when the migration completes; total transfer time depends on data volume but typical instances finish in a few hours. There is no extra charge for a region change.
Yes. Full data export is available at any time, in a portable format you can bring to any infrastructure.

03

Billing, support, and platform

€9 covers everything we do for that app: hardware in the region you choose, daily off-site backups with one-click restore, automatic security patches and version upgrades, 24/7 monitoring, SSL and firewall, and engineering support on Email/LiveChat. There are no setup fees or hidden line items. For more info see our Pricing page.
If you decide to continue, we charge €9/app/month from day 8. If you don't, the trial ends and you can export your data. No card is required for the trial, and we never auto-charge you without explicit consent.
No. The €9/month is flat regardless of how many users log into your app. Add 5 users or 50; the price doesn't change.
24/7 Live chat and email support, both staffed by engineers who run the systems. We handle DNS configuration, SMTP setup, app integrations, performance tuning, troubleshooting, and migration help. Response time is typically under an hour. There is no tier system — every customer gets the same support.
Yes. Cancel from the dashboard. We don't charge a cancellation fee, we don't lock data, and we will export your data to you on request before deletion. data to you on request before deletion.
Every customer instance is backed up daily to a separate region from the primary. We test restores. You can request a restore at any backup point within the retention window — usually 7 days for daily backups.
Your application data sits in the region you choose at provisioning — 21 datacenter locations across six continents. Account-level data (billing, account email, support ticket history) is processed centrally. Application data region is picked by you, per app.
99.9% uptime SLA on every app, every tenant. Service credits are documented at danian.co/service-level-agreement. The status page is located at status.danian.co.
When your tenant approaches the resource ceiling — the base tier holds 1 vCPU/RAM, 30 GB storage — we notify you. Resource upgrades happen with your explicit consent; we will not upgrade your tenant or charge you without it.
We wait. We don't suspend the app or delete your data on the first failed charge. We email you, you fix the card on file, and we continue.
Invoices can be downloaded from the billing dashboard in PDF the day each charge succeeds. EU VAT is added where applicable and the VAT-reverse-charge regime applies for VAT-registered businesses with a valid number.
150+ open-source apps across automation, team chat, file sync, analytics, AI, password management, email marketing, dev tools, project management, smart home, CMS, and federated social. See the full catalog →
Yes. Every instance comes with a web-based terminal and a file manager in your DANIAN management dashboard. Useful for managing your data and customizations.
Resources scale with your usage. If your app needs more vCPU, RAM, or storage, we add it — and we ask first before any change to your plan. €9 is the floor; resource-heavy workloads may price higher, but you'll always know in advance.
Yes. We have both a Partner program and an Affiliate program available. Anybody can sign up.
No contract. No minimum commitment. Cancel anytime from the dashboard with one click. The 7-day free trial requires no credit card. After the trial converts to paid, you can still cancel at any month without notice or penalty.

DEPLOY IN YOUR REGION

21 datacenter locations on six continents

Pick the region closest to your users.

United States, Germany, Finland, Singapore, Australia, Brazil, Canada, Netherlands, UK, Spain, Italy, France, Sweden, Malaysia, India, Japan, Mexico, Poland, South Korea, Chile, South Africa and more coming soon

Global Reach Map

Try managed LanguageTool for 7 days

No card. Cancel from the dashboard.