Kopai vs Lumi: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Kopai and Lumi — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
Kopai
Kopai
Serverless cloud for building, hosting, and monetizing domain-specialized AI agents, with RAG, orchestration, and per-message billing handled for you.
Key features
- Prompt-to-Agent Builder: Write a prompt, upload documents, and try several models side by side — seven steps from blank page to a shipped agent.
- Managed Infrastructure: Kopai holds the model keys, runs the vector database, and keeps the servers alive; you get an endpoint and a readable bill.
- Agent Marketplace: List an agent and get paid per message, keeping 70% of your markup, with every charge logged in an auditable ledger.
- Multi-Model Gateway: One integration across GPT-4o, Kimi K2, Gemini 2.5, Qwen 3, and DeepSeek, switchable at any time.
- Automatic Document Indexing: Upload PDF, DOCX, or XLSX files and Kopai indexes them and handles retrieval behind the scenes.
- Resilient Streaming: Answers resume from where they stopped after a dropped connection or closed tab, with no tokens lost.
- Conversational Agent Creation: Describe the job in ordinary chat and Kopai drafts the agent, picks its organization, and finishes on your approval.
- Kopai for Teams: Seats and roles, team-private agents, shared knowledge, and usage numbers you can check.
Best for
- A lawyer packages case-preparation expertise into an agent and sells access on the marketplace instead of billing hours.
- A consultant turns a library of internal documents into a domain expert clients can query directly.
- A solo creator wants to ship a RAG agent without standing up a vector database or backend service.
- A SaaS company embeds a specialized agent in its own product while letting Kopai handle billing and payouts.
- A team needs private internal agents with role-based access over a shared knowledge base.
- A developer wants to test the same agent across several model providers before committing to one.
Lumi
A Google PAIR prototype that adds AI-powered annotations, granular summaries, and custom Q&A to arXiv research papers.
Key features
- Granular Summaries: Generates summaries at multiple granularities (section- or paragraph-level) to surface key ideas and make long papers easier to skim and comprehend.
- Inline Annotations: Attaches contextual, sentence- or paragraph-specific annotations directly onto the paper text to explain terminology, methods, or results in place.
- Custom Q&A: Lets users ask targeted questions about a paper and receive context-aware answers derived from the document content to clarify methods, results, or motivations.
- arXiv Integration: Built specifically to work with arXiv papers, enabling quick access to preprints and their metadata while preserving original paper structure.
- Open-Source Prototype: Source code available under an Apache-2.0 license on GitHub, allowing inspection, reuse, and community-driven improvements.
- Research Navigation Aids: Provides tools to jump between sections, references, and highlighted insights to streamline literature review workflows.
- Contextual Highlighting: Highlights important sentences and phrases based on AI analysis to draw attention to key contributions and claims.
- Collaboration-Friendly Outputs: Produces shareable annotations and summaries that can be used to coordinate reading lists and group discussions.
- Inline annotations layered on top of arXiv papers
- Granular and multi-level summaries for sections and full papers
- Custom Q&A over the paper content (user-driven queries)
- Lightweight AI layer integrated into the reading interface
- Browser/web-based reading experience (lumi.withgoogle.com)
- Open-source codebase on GitHub (Apache-2.0) allowing local integration and extension
- Designed for improved paper navigation and comprehension
Best for
- Rapid literature review: Quickly generate section-level summaries across many arXiv papers to triage and prioritize reading lists.
- Clarifying complex passages: Ask focused questions about specific paragraphs or figures to get concise, context-aware explanations.
- Teaching and learning: Instructors and students use inline annotations and summaries to make advanced papers accessible in coursework.
- Collaborative annotation: Teams annotate papers with AI-generated notes to share insights and discussion points during journal clubs or research meetings.
- Relevance triage: Determine whether a paper contains needed methods or results without reading it end-to-end by scanning AI-highlighted passages and summaries.
- Research discovery: Identify related work and key contributions faster by surfacing dominant themes and claims within a paper.
- Accelerating literature reviews and paper digestion for researchers
- Explaining complex methods or equations within academic papers
- Creating Q&A study aids from research articles
- Annotating and sharing insights on arXiv papers within teams
- Prototyping integrations that enhance document-based workflows