useSignal is listed as active in the registry but did not answer our last check. It exposes 12 tools. Last commit 28 Oct 2026.
QR codes, JSON diff/format, hashes, JWT, cron, timestamps, placeholders, flowcharts, forms, regex.
Uptime history
36 days of history · worst day 0%
36 days agonow
4.4%
Uptime 24h
4 of 91 checks
12
Tools
read from the server
255 ms
Response time
average over 24h
0
Stars
last commit 28 Oct 2026
useSignal does not always answer
Over the last week it answered 10.5% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.
Connect this server
Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 12 min ago.
run in your terminal
claude mcp add usesignal --transport http https://www.usesignal.dev/mcpSettings → Connectors → Add custom connector, then paste this address
https://www.usesignal.dev/mcp~/.codex/config.toml
[mcp_servers.usesignal]
url = "https://www.usesignal.dev/mcp".cursor/mcp.json
{
"mcpServers": {
"usesignal": {
"url": "https://www.usesignal.dev/mcp"
}
}
}.vscode/mcp.json
{
"servers": {
"usesignal": {
"type": "http",
"url": "https://www.usesignal.dev/mcp"
}
}
}Available tools 12
Read directly from the server with tools/list, grouped by what they act on.
If a tool disappears, we record the date.
usesignal
usesignal_convert_timestamp
Convert a Unix timestamp (seconds or milliseconds) or an ISO 8601 date into ISO, UTC, epoch seconds/milliseconds, a relative time and the local time in a given time zone.
usesignal_diff_json
Compare two JSON documents structurally and list every added, removed and changed value with its JSONPath. Numbers compare exactly. Arrays match by content by default, so an inserted item shows as one addition; use arrays:"position" to compare index by index.
usesignal_encode_decode
Exact text transforms: Base64 encode/decode (UTF-8), URL encode/decode, decode a JWT header and payload with readable exp/iat/nbf dates (the signature is not verified), or hash text with MD5, SHA-1, SHA-256 and SHA-512. Use this instead of computing hashes or Base64 by hand.
usesignal_explain_cron
Explain a standard 5-field cron expression (minute hour day-of-month month day-of-week) in plain English and list its next run times in a given time zone, handling daylight saving time.
usesignal_flowchart
Turn JavaScript/TypeScript code, arrow steps or Mermaid-style arrows into a flowchart, returned as Mermaid source and an SVG diagram. Steps mode uses one flow per line: "Start -> Validate -> Save" and branches like "Validate -- No --> Show error".
usesignal_format_json
Validate, pretty-print or minify JSON, optionally sorting keys. Invalid JSON reports the exact line and column; with repair (default on) it fixes common problems such as trailing commas, single quotes, comments and unquoted keys, and lists each fix.
usesignal_generate_colors
Generate light and dark semantic color tokens from a six-digit hex brand color. Returns a shade scale, measured text contrast checks and CSS, JSON and Tailwind exports. This measures listed color pairs only, not whole-page accessibility. Call usesignal_open_workbench with the result input to preview.
usesignal_generate_form
Generate an editable form from a JSON object. Returns nested field paths, JSON Schema, HTML, React JSX and config exports. Arrays and nulls use JSON textareas. Values are processed in memory; avoid secrets. To show an interactive preview, call usesignal_open_workbench with this result input.
usesignal_generate_qr
Generate a scannable QR code for a link, text, Wi-Fi network, contact card (vCard), email, SMS, phone number, WhatsApp chat or UPI payment. Returns the encoded payload, an SVG file and a PNG preview image. values by type: url{url}; text{text}; wifi{ssid,password,security:WPA|WEP|nopass,hidden}; vcard{firstName,lastName,phone,email,org,title,website,address}; email{to,subject,body}; sms{phone,message}; phone{phone}; whatsapp{phone,message}; upi{vpa,name,amount,note}.
usesignal_open_workbench
Show the editable useSignal UI. First call a useSignal data tool, then pass its returned input and matching tool name. Recomputes from validated inputs; no shared state.
usesignal_placeholder_image
Create a placeholder image URL (served by usesignal.dev) plus HTML, Markdown and CSS snippets, for mockups, prototypes, seed data and layouts. Width and height up to 4000 px.
usesignal_test_regex
Execute a JavaScript regular expression against text and expected match/non-match test cases. Returns indexed matches and capture groups. Flags use JavaScript semantics. Execution times out after 500ms. Call usesignal_open_workbench with result input to highlight matches.
Endpoints
| URL | Transport | State | Latency | Checked |
|---|---|---|---|---|
| https://www.usesignal.dev/mcp | streamable-http | answering | 86 ms | 12 min ago |
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useSignal — questions
Answers built from our own checks of this server.
What can useSignal do?
It exposes 12 tools, read directly from the server on our last check. Among them: usesignal_convert_timestamp, usesignal_diff_json, usesignal_encode_decode, usesignal_explain_cron, usesignal_flowchart, usesignal_format_json and 6 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 →
Is useSignal working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 4 of 91 checks got a reply (4.4%), average response time 255 ms. The bar chart above shows every period we have measured.
The registry lists useSignal as active — why does it not respond?
The official MCP registry stores what the author submitted; it does not verify that the server still runs. We check the endpoint ourselves, and this one does not answer. Catalogues that copy the registry without checking will show it as working.
How do I connect useSignal?
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 useSignal need an API key?
No. useSignal completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 12 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is useSignal?
It answers our handshake in 255 ms on average, which is faster than 53% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.
Is useSignal open source?
The code is open source: it is published under the MIT licence and 0 stars on GitHub. The licence covers the code in the repository, not the hosted service at usesignal.dev, which runs on its operator's own terms.