The Payload Validator MCP server,
connected in one click.
Validate JSON, YAML, XML and CSV with exact line/column errors and silent-corruption warnings. Connect the official Payload Validator MCP server to Claude, ChatGPT, or Cursor through gate — one gateway URL, no config files, security-checked.
Free to start · No credit card · No hosting needed
Add Payload Validator to your AI in one minute
Pick your client. Copy, paste, done — or let gate handle sign-ins and policies for you.
claude mcp add --transport http payload-validator https://payload-validator.gumballtools.com/api/mcpRun in your terminal, then restart Claude Code.
Payload Validator · https://payload-validator.gumballtools.com/api/mcp
What your AI can do with Payload Validator
Real prompts you can type the moment it's connected — no setup, no docs to read.
“Use “validate_json”: Validates a JSON document and reports every problem with an exact line and column. Use this whenever you need to know why a JSON payload is.”
“Use “validate_yaml”: Validates a YAML document, including the values that mean different things to different YAML loaders. Use this for any YAML you are about t.”
“Use “validate_xml”: Validates an XML document for well-formedness, namespace correctness, and the entity-based attacks that arrive as XML. Use this before pars.”
“Use “validate_csv”: Validates CSV text against RFC 4180 and reports ragged rows individually, with both field counts. Use this before loading a CSV, and whenev.”
How secure is the Payload Validator MCP server?
Every server in the gate directory has to pass the same four checks before your AI can touch it. Here's how Payload Validator holds up.
Official endpoint
Operated by Payload Validator (gumballtools.com) at its documented MCP endpoint — not a third-party mirror or community re-host.
No sign-in needed
This server only exposes public data — no account and no credentials are involved when you connect.
Scanned before it goes live
gate checks every tool for prompt injection, hidden instructions, data-exfiltration hints, and over-broad permissions before the server is available through your gateway.
Watched for drift
If Payload Validator adds or changes tools later, gate re-scans and alerts you — before your AI acts on the change.
Connected in three steps
Connect your gate
Add one gateway URL to Claude, ChatGPT, or any MCP client. One-time setup, about two minutes.
Pick Payload Validator
Choose Payload Validator in the gate directory. No sign-in needed.
Use it anywhere
Payload Validator's tools are live in every AI client you've connected — with rules and logging built in.
Free to start · No credit card · No hosting needed
The actual tools Payload Validator exposes
Fetched live from the official endpoint and re-checked daily by gate — not marketing copy.
validate_json — Validates a JSON document and reports every problem with an exact line and column. Use this whenever you need to know why a JSON payload is
validate_yaml — Validates a YAML document, including the values that mean different things to different YAML loaders. Use this for any YAML you are about t
validate_xml — Validates an XML document for well-formedness, namespace correctness, and the entity-based attacks that arrive as XML. Use this before pars
validate_csv — Validates CSV text against RFC 4180 and reports ragged rows individually, with both field counts. Use this before loading a CSV, and whenev
validate_auto — Detects whether a payload is JSON, YAML, XML or CSV, then validates it. Use this when you have a blob of text and do not know what it is —
Who runs the Payload Validator MCP server?
The Payload Validator MCP server at a glance
https://payload-validator.gumballtools.com/api/mcpQuestions, answered
Is there an official Payload Validator MCP server?
Yes — Payload Validator operates its own remote MCP server at payload-validator.gumballtools.com. gate connects you to that official endpoint and adds security scanning, per-tool access rules, and an activity log on top.
How do I connect Payload Validator to Claude or ChatGPT?
Add gate's gateway URL to your AI client once, then pick Payload Validator in the directory. No account or sign-in is needed. From then on, Payload Validator's tools are available in every client you've connected to gate.
Do I need to host anything?
No. Payload Validator runs the server, and gate is fully managed. You just connect one URL — there's nothing to install, deploy, or maintain.
Is the Payload Validator MCP server safe to connect?
It's the vendor's official endpoint, and gate scans its tools for prompt injection and hidden instructions before it goes live, re-checks it whenever it changes, and lets you allow, block, or require approval for every single tool.
Is it free?
Yes — you can get started with gate for free and connect Payload Validator in minutes. No credit card required.
Connect more than just Payload Validator
Every server below works through the same gateway URL — connect once, add tools anytime.
Squarespace DomainsDesignView →Set up Payload Validator in: Claude · Claude Code · ChatGPT · Cursor · VS Code
Give your AI Payload Validator — safely.
One URL. All MCPs. Full control. Free to start.
Get started free