x402 Universal Payer

Discover and pay x402 endpoints with spend caps and safer automated access.

Stars

★ 241

Source

Official Registry

Updated

2026-08-19

// securityHigh risk

Requires keys· MCP_BRIDGE_EVM_PRIVATE_KEY, MCP_BRIDGE_SVM_PRIVATE_KEY, MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC, MCP_BRIDGE_MAX_TOTAL_ATOMIC, MCP_BRIDGE_ALLOWED_PAYTO, MCP_BRIDGE_ALLOWED_HOSTS, MCP_BRIDGE_ALLOW_HTTP, MCP_BRIDGE_DISCOVER_LIMIT, MCP_BRIDGE_BAZAAR_URL, MCP_BRIDGE_BATCH_DEPOSIT_MULTIPLIER, MCP_BRIDGE_MAX_DEPOSIT_ATOMIC, X402_MCP_BRIDGE_CHANNELS_DIR, RPC_URL_8453
Runs locally
Official / curated
Open source
Community-trusted

Summary

This MCP tool comes from an official registry, is open source, and has recent updates, with no obvious malicious red flags in the provided material. However, its core function uses blockchain private keys for automatic payments and may connect to discovered x402 endpoints and chain RPCs, so strict spend caps and allowlists are important.

CredentialsHigh risk

It requires MCP_BRIDGE_EVM_PRIVATE_KEY and MCP_BRIDGE_SVM_PRIVATE_KEY, which can directly authorize on-chain payments. Combined with the stated 'auto-paying bridge' capability, leakage, misconfiguration, or induced use could lead to real fund spending. MAX_PRICE/MAX_TOTAL/ALLOWED_* settings help mitigate this, but the credentials are highly sensitive and carry a clear risk of monetary misuse.

Network egressCaution

No fixed remote host is listed, but the description indicates it can pay x402 endpoints on the open web and use Bazaar discovery. The presence of RPC_URL_8453, MCP_BRIDGE_BAZAAR_URL, ALLOWED_HOSTS, and ALLOW_HTTP also shows it may connect to discovery services, blockchain RPC, and allowed payment endpoints. This is typical network behavior for this type of tool, but host allowlists and any HTTP enablement should be reviewed carefully.

Code executionCaution

The system checks indicate that this tool executes code/spawns processes. For an MCP tool, this is a normal capability. The provided material does not show system permissions clearly beyond its stated function, nor any suspicious execution chain, but it should still be run with least privilege and in a constrained host environment.

Data accessCaution

The presence of X402_MCP_BRIDGE_CHANNELS_DIR suggests it may read/write local channel or state data. Together with private keys and spend settings, related local files may contain sensitive financial or channel information. The material does not indicate broad file-system access beyond its payment function, so this currently looks like limited local state access rather than excessive authorization.

Supply chainCaution

It comes from an official registry, has a public open-source repository, and was updated within the last year, all of which are positive supply-chain signals. However, the missing README, unspecified license, and 0-star community adoption reduce verifiability and maturity confidence. Overall, supply-chain risk does not appear high, but source and dependency review is still advisable before deployment.

Recommendations

Use dedicated low-balance wallets only, and enforce strict MAX_PRICE_PER_CALL, MAX_TOTAL, and MAX_DEPOSIT limits.
Set ALLOWED_HOSTS and ALLOWED_PAYTO carefully, and avoid enabling ALLOW_HTTP unless absolutely necessary.
Store private keys in a secure secret-management solution and avoid long-lived plaintext environment exposure.
Review the source code and dependencies before deployment, especially the payment flow, discovery logic, and local channel-directory read/write behavior.

Audited by: gpt-5.4 · 2026-06-16

// install

Copy the install command and let the AI configure it · recommended for beginners

Please install the "x402 Universal Payer" MCP server from askskill:
Run: claude mcp add 'io-github-nirholas-x402-bridge' -- npx -y @three-ws/mcp-bridge

// docs

No documentation provided

Check the source repo for usage and examples.

Go to source repo ↗

Check trust and reliability scores for x402 endpoints.

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