Loop Gateway · Developer tool
Check the challenge.
Before you pay.
A free, offline reader for L402 payment challenges. Paste the 402 response and see whether the macaroon, the invoice, the advertised amount and the announced payment hash actually agree with each other.
The challenge
Paste the raw 402 response.
Include the status line, every header, then a blank line and the body. A bare JSON body also works, and the missing status is reported.
What it checks
Four things that must agree.
- The response is 402 and offers the L402 scheme.
- The macaroon decodes as base64 and carries the version current clients expect.
- The invoice is valid BOLT11, and its amount and payment hash can be read out of it.
- The amount and hash the body advertises match the invoice itself.
The checker runs entirely in this tab. It makes no network request, stores nothing, and never reads a wallet, a token or a payment preimage. Your pasted text is not uploaded.
Report
Scope
A challenge is not a delivery.
A conformant challenge only means a client can read the price and pay it. It does not mean the invoice will settle, that the credit will be claimed, or that the paid request will be answered. Those are separate checks, and this tool reports them as separate steps rather than folding them into one green light.
The payee signature is structurally present in the invoice this tool reads, but it is not cryptographically verified here, and the tool says so rather than implying more.
Build with us
Bring one real workflow.
Building an agent that buys inference with Lightning? Paste a challenge from your own server, run it here, and tell us which finding surprised you.
Do not send wallet keys, bearer tokens, payment preimages or customer data.