Best On-Premises AI Writing Software of 2026

ONLYOFFICE Docs is a secure online office suite for teams and businesses of all sizes. Create and edit docs, sheets, slides, fillable forms and PDFs. Collaborate with your teammates in real time using two co-editing modes, version history and other tools. Enable the AI assistant of your choice — ChatGPT, DeepSeek, Mistral, Groq AI, etc. Generate new content, summarize, translate and do more with your favourite AI tool while working on office files. Integrate ONLYOFFICE Docs into your business platform, whether it be Odoo, Alfresco, Confluence, Pipedrive, Nextcloud, Redmine, SuiteCRM, etc., via an integration app (40+ available integrations). Use Docs within ONLYOFFICE DocSpace, a room-based document collaboration platform equipped with the online office suite. Create dedicated spaces for different purposes, invite your teammates, assign access permissions and collaborate the way you like. With DocSpace, you can store, share and co-edit office files, and even interact with third parties.

LocPilot is an innovative Word Add-in designed to integrate the capabilities of large language models directly into Microsoft Word, all while ensuring complete privacy and security—there's no reliance on cloud services or data sharing. Unlike conventional AI tools that transmit your information to external servers, LocPilot operates solely on your local machine, safeguarding your documents from any potential breaches. This tool allows your team to function offline, free from the need for an internet connection, while still harnessing the advanced features of state-of-the-art language models. Users can seamlessly utilize their preferred local LLMs within Microsoft Word, merging the ease of Word's interface with superior language processing capabilities. The flexibility to alternate between various models not only enhances productivity but also guarantees total data confidentiality, eliminating the burden of ongoing subscription fees. With LocPilot, users gain comprehensive control, adaptability, and a sense of security that empowers their work. Ultimately, it transforms the way teams approach document creation and editing, enabling enhanced collaboration and efficiency.

ProWritingAid helps companies produce better content, comms and reports, bids, and other documents faster. ProWritingAid eliminates common errors such as inconsistent terminology, context spelling errors, grammar mistakes, and poor style. There are many integration options available, including API and on site solutions. This supports all sizes of organizations, even those with privacy and security requirements.

DocsGPT is a self-hostable, MIT-licensed RAG platform for building private AI knowledge bases and autonomous agents on your own infrastructure. No cloud dependency required. Stack: Python/Flask backend, React/TypeScript frontend, vector databases (Qdrant, MongoDB, Elasticsearch and more), and support for every major LLM provider — OpenAI, Anthropic, Google Gemini, and local inference. Deploy via Docker or Kubernetes. Full REST API with scoped API keys. Ingest PDFs, DOCX, CSV, XLSX, HTML, audio (MP3/WAV/M4A), GitHub repos, sitemaps, and live databases. Build multi-step agentic workflows using a visual node editor, custom tool definitions, API calls, webhooks, and code execution. Embed chat or search widgets into any site in minutes. Connect to Slack, Telegram, Discord, or any service via REST API. Enterprise plan adds RBAC, team analytics, and dedicated support. 18,000+ GitHub stars. Active release cadence.

AI assistant for customer-facing departments. Sapling works with messaging platforms and CRMs to assist agents in creating personalized responses. Managers can gain conversational insights that will help them coach and prepare their teams. Sapling offers functionality for autocomplete, spelling, grammar checking, as well as snippets/canned message/text expander. All services can be hosted on-premise or in the cloud to meet security and privacy requirements. The Grammar and Spelling APIs allow Sapling's language models to be integrated into custom applications and use-cases. Sapling Suggest pulls relevant answers from a team knowledge database and allows agents to respond faster to customer inquiries by clicking on the desired response. Instead of giving brittle, decision tree-based chatbots, empower agents.

Would you like to edit text without switching between multiple applications? Our text editor offers everything you need for a smooth workflow, from syntax highlighting and word compatibility to Figma integration.