# App-Kit

> App-Kit — free web tools for developers and site owners: image compression, WebP/AVIF conversion, resizing and a 400-point website SEO audit. They work in the browser with no sign-up; the same operations are available via an API paid by credits.

app-kit.dev is the English version. The tools are free with no watermarks; compression and conversion run on the App-Kit processing service, resizing runs in the browser. The SEO audit checks a site against a 400-point canon (36 groups) and returns a 0–100 score and a PDF report.

## Tools

- [Image Compressor](https://app-kit.dev/tools/image-compressor): Compress images online — JPG, PNG and GIF to WebP or AVIF. Quality control, batch mode, before/after. Free, no sign-up, no watermarks.
- [WebP / AVIF converter](https://app-kit.dev/tools/image-converter): Convert JPG, PNG and HEIC to WebP or AVIF online: drop a file, download the result. Batch mode, up to 5 files at a time. Powered by the App-Kit API.
- [Image Resizer](https://app-kit.dev/tools/image-resizer): Resize and crop images online: width and height in pixels, 1:1, 16:9 and 4:3 presets, export to JPG, PNG or WebP. Free, no sign-up.
- [SEO Audit](https://app-kit.dev/tools/seo-audit): Free SEO audit: paste a URL and get a score with a fix list — meta tags, headings, alt attributes, indexing basics. By App-Kit, no sign-up.
- [Text Analyzer](https://app-kit.dev/tools/text-analyzer): Free online text checker: readability grade, keyword stuffing, filler share, top words, filler phrases and grammar. Up to 20,000 characters, no sign-up.
- [PDF to image converter](https://app-kit.dev/tools/pdf-to-image): Turn every PDF page into a JPG, PNG or WebP image. Pick the resolution, preview the pages and download them one by one or as a ZIP. Free, no sign-up.

## MCP server for AI agents

The same tools are available to AI agents over the Model Context Protocol: Claude Code, Claude.ai, Cursor and VS Code call the SEO audit, text check, PDF and image conversion themselves. Free with daily limits: use it without an account (optionally with a token that needs no email), or sign in with a free App-Kit account for higher limits.

- [Setup and free token](https://app-kit.dev/mcp): App-Kit tools in Claude, Cursor and VS Code over MCP: SEO audits, text checks, PDF and image conversion. Try without an account or sign in for higher limits.
- Server URL (Streamable HTTP): https://mcp.app-kit.dev/mcp
- Server URL with an App-Kit account (OAuth sign-in): https://mcp.app-kit.dev/mcp/account
- Server name in client settings: app-kit
- Tools: seo_audit_fast, seo_audit_status, text_check, pdf_to_images, images_to_pdf, image_convert, image_compress, conversion_status, create_upload, quota_status

## Guides and case studies

- [State of SEO on the Russian web 2026: a study of 901 sites](https://app-kit.dev/blog/seo-runeta-2026): An App-Kit study of 901 sites in the .ru and .рф zones from the Tranco top 1M, up to 10 pages each. 58% have no canonical tag, 69% no JSON-LD, 79% no CSP, and only 8% publish an llms.txt.
- [AI SEO audit: how to make your site visible to ChatGPT, Perplexity and AI Overviews](https://app-kit.dev/blog/ai-seo-audit): We checked robots.txt and llms.txt on 25 SaaS sites and 21 large Russian sites. 17 of 25 SaaS sites ship an llms.txt, only 3 Russian sites do, and 5 more return an HTML page with a 200 status instead of the file.
- [How to Convert a PDF to JPG, PNG or WebP (and Which Resolution to Pick)](https://app-kit.dev/blog/pdf-to-jpg-png-webp): Every PDF page can become its own image. We ran three documents through our converter at 96, 150 and 300 dpi and compared JPG, PNG and WebP: JPG came out 8.5 times heavier than PNG for a diagram, and WebP was 10 times lighter for a scan.
- [Online Text Checker: Readability, Keyword Stuffing, Filler and Grammar](https://app-kit.dev/blog/text-check-online): Seven scores that tell you a draft needs another pass: readability, keyword stuffing, filler share, keyword density, top words, clichés and grammar. Targets, formulas and one paragraph measured before and after an edit.
- [Free Online SEO Audit: 400-Point Website Check with a Score and PDF](https://app-kit.dev/blog/seo-audit-online): An online audit runs your site through 400 checks in 36 groups and returns a 0–100 score with priorities. We audited our own site, scored 70.5, and break down every finding.
- [How to Resize an Image Online: The Complete Guide](https://app-kit.dev/blog/resize-image-online): Resizing to the width you actually need cuts up to 86% of file weight. When to resize, when to crop, when to compress — with honest measurements of one real photo.
- [WebP vs JPG vs PNG: which image format to use in 2026](https://app-kit.dev/blog/webp-vs-jpg): One image, four formats, a real test with our converter: WebP is 45–50% lighter than JPG, PNG is 5× heavier. Here is when each format wins.
- [How to convert AVIF to JPG (3 ways)](https://app-kit.dev/blog/avif-to-jpg): Saved an image from a site and got an .avif your editor won't open? Three ways to get a JPG — with real timings and the transparency catch.
- [Technical SEO audit checklist: 18 checks that actually matter](https://app-kit.dev/blog/seo-audit-checklist): 18 checks from our SEO audit canon in six groups — with IDs, priorities and fixes. Plus a real case: our own site went from 70.5 to 93.

## Company

- [Team](https://app-kit.dev/team): the people behind App-Kit
- [Research](https://app-kit.dev/research): the AppKitResearchBot crawler, what it collects and how to opt out
- [Privacy Policy](https://app-kit.dev/privacy): what data is processed and why
- [Terms of Use](https://app-kit.dev/terms): rules for using the tools

## Optional

- [Full site content for LLMs](https://app-kit.dev/llms-full.txt)
- [Sitemap](https://app-kit.dev/sitemap.xml)
- [Русская версия (app-kit.ru)](https://app-kit.ru/llms.txt)