YangOpen is answering right now. Last checked 10 min ago. It exposes 13 tools.
Vietnamese-first text to speech, photo tools, Word to PDF and TCVN3/VNI fixes. Free daily allowance.
Uptime history
15 days of history · worst day 97%
15 days agonow
100.0%
Uptime 24h
91 of 91 checks
13
Tools
read from the server
200 ms
Response time
average over 24h
open, no key
Access
streamable-http
What changed 9
Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 7 November 2026. No other catalogue keeps this.
7 Nov
4 tools appeared
count_text, excel_to_pdf, number_to_words and 1 more
7 Nov
4 tools disappeared
count_text, excel_to_pdf, number_to_words and 1 more
7 Nov
a tool description was rewritten
get_upload_link
Tools have disappeared from this server
A tool that vanishes takes a piece of your agent with it, and the change arrives silently. Watch this server and every such change lands in your inbox.
Connect this server
Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 10 min ago.
run in your terminal
claude mcp add mcp --transport http https://yangopen.com/mcpSettings → Connectors → Add custom connector, then paste this address
https://yangopen.com/mcp~/.codex/config.toml
[mcp_servers.mcp]
url = "https://yangopen.com/mcp".cursor/mcp.json
{
"mcpServers": {
"mcp": {
"url": "https://yangopen.com/mcp"
}
}
}.vscode/mcp.json
{
"servers": {
"mcp": {
"type": "http",
"url": "https://yangopen.com/mcp"
}
}
}Available tools 13
Read directly from the server with tools/list, grouped by what they act on.
If a tool disappears, we record the date.
convert
convert_time
What a time in one place is in other places, with daylight saving applied for that date. Name zones the IANA way (Asia/Ho_Chi_Minh, America/New_York, Europe/London, Australia/Sydney) or UTC. Free.
convert_vietnamese_font
Turn Vietnamese text typed in the old fonts (TCVN3/ABC such as .VnTime, or VNI such as VNI-Times) into Unicode, so it reads right in any font: "Céng hßa x· héi chñ nghÜa" becomes "Cộng hòa xã hội chủ nghĩa". The old font is guessed from the text unless you name it. Up to 5,000 characters a call. Free. For a whole Word or Excel file, send the user to https://yangopen.com/vi/tools/font-to-unicode/.
text
text_to_speech
Turn text into speech with a free YangOpen voice and get a link to the MP3. It costs no credit; it counts against the user's free daily allowance. Up to 3,000 characters per call: split longer text at sentence ends and call once per part. The link works for 24 hours; give it to the user exactly as returned. The text is sent to an outside speech service to be read; it is not stored.
text_to_speech_plus
Turn text into speech with a Plus voice and get a link to the MP3. Spends the user's prepaid YangOpen credit: 25 credits per 1,000 characters, rounded up to whole credits. The charge is made only when the MP3 is ready, and the answer states what was charged and the balance left. Up to 1,000 characters per call for Vietnamese voices and 400 for the other languages; split longer text at sentence ends. Before a long job, tell the user the cost (characters ÷ 1,000 × 25 credits) and check get_balance. The link works for 24 hours; give it to the user exactly as returned.
background
remove_background
Cut the main subject out of a photo and get a PNG with a transparent background. 5 free runs a day for each image tool, then 25 credits a run, charged only when the result is ready. Give the photo as file_id (the user uploads it through get_upload_link) or image_url. The result link works for 24 hours; give it to the user exactly as returned.
balance
get_balance
The user's YangOpen credit balance, what it buys (Plus voice characters, paid image runs), the prices, and where to top up. Changes nothing.
colorize
colorize_photo
Colour a black-and-white or toned (sepia) photo, with faces restored. A photo that already has colour comes back as it was and costs nothing. 5 free runs a day for each image tool, then 25 credits a run, charged only when the result is ready. Give the photo as file_id (the user uploads it through get_upload_link) or image_url. The result link works for 24 hours; give it to the user exactly as returned.
expand
expand_image
Extend a photo with AI-painted surroundings: to a new shape such as 16:9 (a cover), 9:16 (a phone story) or 1:1, or by a share of its size on the sides you choose. It never crops: the original pixels stay as they were. Can take up to a minute. 5 free runs a day for each image tool, then 25 credits a run, charged only when the result is ready. Give the photo as file_id (the user uploads it through get_upload_link) or image_url. The result link works for 24 hours; give it to the user exactly as returned.
scan
scan_document
Turn a phone photo of a page (a document, a receipt, a page of a book) into a flat, straight scan: the page is found, cut out of the background and unbent, and comes back as a JPEG. 5 free runs a day for each image tool, then 25 credits a run, charged only when the result is ready. Give the photo as file_id (the user uploads it through get_upload_link) or image_url. The result link works for 24 hours; give it to the user exactly as returned.
sharpen
sharpen_image
Make a blurry, small or old photo sharp and larger (AI upscaling). It can also restore faces, and clean scratches and dust from an old print. 5 free runs a day for each image tool, then 25 credits a run, charged only when the result is ready. Give the photo as file_id (the user uploads it through get_upload_link) or image_url. The result link works for 24 hours; give it to the user exactly as returned.
upload
get_upload_link
A one-time page where the user uploads a file for the tools that need one: a photo (JPEG, PNG or WebP) for the image tools and scan_document, or a Word file (.docx or .doc) for word_to_pdf, up to 25 MB. It gives the file_id to pass to them. You cannot hand over a file from this chat yourself: give the user the link, ask them to open it and choose the file, and continue when they say it is done. In a client that can run shell commands (Claude Code), upload a local file yourself with the upload_command. The link works for 1 hour; the file is kept for 24 hours. Free.
voices
list_voices
The YangOpen voices. tier "free" (default): sixteen free voices — two Vietnamese (Southern accent), American and British English, Mandarin, Japanese, Korean, Thai, French and Spanish. tier "plus": the paid voices, about 2,600 — 182 Vietnamese (Northern, Central and Southern), English, Spanish, Mandarin, French, Japanese and Korean; search them by language, gender and words in the name or style. Returns the id to pass to text_to_speech (free) or text_to_speech_plus (plus).
word
word_to_pdf
Turn a Word document (.docx or .doc, up to 25 MB) into a PDF with the layout Word gave it, on YangOpen's server. A few hundred pages take under half a minute; a much longer document may not finish. 5 free files a day, then 25 credits a file, charged only when the PDF is ready. Give the file as file_id (the user uploads it through get_upload_link) or file_url. The PDF link works for 24 hours; give it to the user exactly as returned.
Tools removed
Tools this server used to expose. Anything built against them stopped working on the day they went.
count_text
removed 7 Nov 2026
excel_to_pdf
removed 7 Nov 2026
number_to_words
removed 7 Nov 2026
powerpoint_to_pdf
removed 7 Nov 2026
Endpoints
| URL | Transport | State | Latency | Checked |
|---|---|---|---|---|
| https://yangopen.com/mcp | streamable-http | answering | 209 ms | 10 min ago |
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YangOpen — questions
Answers built from our own checks of this server.
What can YangOpen do?
It exposes 13 tools, read directly from the server on our last check. Among them: colorize_photo, convert_time, convert_vietnamese_font, expand_image, get_balance, get_upload_link and 7 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README.
How MCP servers expose tools in the first place →
What is YangOpen mostly used for?
Its tools cluster around convert and text. That is what this server is built to work with — the grouping comes from the actual tool names, not from a category we assigned.
Is YangOpen working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 91 of 91 checks got a reply (100.0%), average response time 200 ms. The bar chart above shows every period we have measured.
Did YangOpen ever remove tools?
Yes. count_text, excel_to_pdf, number_to_words, powerpoint_to_pdf are no longer exposed — we recorded the date each one disappeared. A tool vanishing usually means a breaking change for anything that depended on it.
How do I connect YangOpen?
Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does YangOpen need an API key?
No. YangOpen completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 13 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is YangOpen?
It answers our handshake in 200 ms on average, which is faster than 67% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.