Features

Tentaco bundles 382+ free online tools into focused studios. Most processing happens locally in your browser — no sign-up required.

17 live studios

PDF, image, video, HTML, code, text, audio, data, design, SEO, security, calculator, finance, API, converter, letter and document workspaces.

Developer tools

JWT inspector, OpenAPI viewer, HAR viewer, CSP generator, DNS lookup, SSL certificate viewer, CORS tester and more in API Studio.

Privacy by design

Most tools never upload your files. Optional server features (file share, DNS/SSL lookup, HTTP proxy) are clearly marked.

German & English

Full UI in Deutsch and English. Letter and document templates follow DIN 5008 and German business conventions.

All studios

Click a studio to open its workspace and switch modes from the sidebar.

PDF Studio

Merge, compress and transform PDFs locally

20+ grouped modes
No upload to server
Page tools

Image Studio

Compress, convert and apply image effects

16 modes
Canvas effects
Base64 & palette

Video Studio

FFmpeg in the browser — trim, GIF, convert

12 modes
Local FFmpeg.wasm
Up to 100 MB

HTML Studio

Live HTML, CSS & JavaScript with instant preview

Split editor & preview
Syntax themes
Device frames

Code Studio

Format, validate and convert JSON, XML, SQL and web code

JSON & YAML
HTML/CSS/JS minify
SQL & GraphQL

Text Studio

Text utilities in one switching workspace

Find & replace
Case tools
Extract emails/URLs

Audio Studio

Trim, convert and enhance audio locally

Extract from video
MP3/WAV convert
Trim & metadata

Data Studio

CSV, tables and data transformation tools

CSV ↔ JSON
TSV converter
HTML table builder

Design Studio

Colors, gradients and visual design utilities

Color palettes
Gradient builder
CSS generators

Web & SEO Studio

Meta tags, sitemaps and SEO analysis tools

Meta tag editor
Open Graph
Sitemap tools

Security Studio

Hashing, encryption and security utilities

Hash generators
JWT tools
Password strength

Calculator Studio

Math, dates, health and utility calculators in one workspace

35 calculator modes
Math & statistics
Dates & timers

Finance Studio

Loans, taxes, margins and pricing calculators in one workspace

13 finance calculators
Loans & mortgages
Tax & pricing

API Studio

HTTP requests, networking and API utilities in one workspace

HTTP client & cURL
Subnet & MAC tools
Webhooks & status codes

Converter Studio

Units, encoding, data sizes, timezones and file sharing in one workspace

Unit converter
Binary & Roman
Bytes & bandwidth

Letter Studio

Business letters, cancellations and applications with DIN 5008 guide

DIN 5008 guide
General letter
Cancellations

Document Studio

Invoices, receipts and resumes as fill-in PDF templates

Document guide
Invoice template
Receipt

Known limitations

Some newer tools have documented constraints — we prefer honest limits over fake promises.

PDF bookmark editing is view-only; pdf-lib does not support full outline editing.
Watermark removal uses simple blending, not AI. ICO export is PNG-based, not multi-size binary.
Video tools require FFmpeg.wasm (large download on first use). DNS/SSL lookups use server routes with rate limits.
OpenAPI viewer accepts JSON only (no YAML parser yet). CORS and robots.txt tests use the optional HTTP proxy.

Read the docs