Komodo PDF vs Mozilla PDF.js

Komodo PDF is a free, GPLv3 open-source PDF reader for Windows, macOS, and Linux. Its local-first reader supports continuous scrolling, zoom, fit-width and fit-page views, document outlines, and text selection. An AI panel answers questions using passages indexed in a local vector store. Clicking a citation takes you to the cited passage and highlights it, while a per-page badge marks pages without a text layer, such as scanned images. If the document cannot answer, the assistant can use general knowledge and indicate that fallback. Chat works with OpenAI-compatible providers using your own API key and with local chat endpoints. The maker says Komodo has no backend, sends no telemetry, and does not upload documents to Komodo; remote chat sends retrieved passages to the configured provider. With local ONNX embeddings and a local chat endpoint, documents are said to remain on the laptop. API keys use the operating-system keyring with an encrypted disk fallback. Windows downloads include EXE, MSI, and portable ZIP files, with published SHA-256 checksums. Version 0.1.1 is displayed.

Mozilla PDF.js is a free, web standards-based platform for parsing and rendering PDF files. Developers can use its display API to render documents and retrieve information, or adapt the viewer layer for a custom interface. That viewer is used in Firefox and project browser extensions. PDF.js renders annotations and supports adding a subset of annotation types, and it supports form filling; OCR is not provided. The project targets HTML5-compliant browsers and includes a legacy build for older browsers, although PDF feature support varies by browser and version. Prebuilt builds are available, with hosted copies listed through jsDelivr, cdnjs, and unpkg. Developers can clone and build it locally, but some browsers require a local web server instead of opening PDFs through file URLs. Cross-origin requests are blocked by default, so CORS or a server proxy may be needed. For large documents, rendering only visible pages can reduce memory use. PDF.js is licensed under Apache 2.0.