The referenced Lightspark SSP server implementation is not publicly accessible

What the evidence shows

Technical and product details

1. Documented behavior

   Spark's public README directs engineers testing local SSP changes to run sparkcore.server from Lightspark's webdev project and links to a server-side Sparkcore test. The referenced repository URL returned 404 without authentication when rechecked on 2026-07-13. 12

   Supporting material shown on this page

   Sparkcore SSP instructionsPinned source code · github.com · checked 2026-07-14

   254## Testing against local SSP changes
   255
   256To run the server with local changes go to your sparkcore folder in the lightspark webdev project:
   257
   258```
   259export QUART_APP=sparkcore.server
   260export QUART_ENV=development

   referenced non-public implementationReferenced non-public implementation · github.com · checked 2026-07-14
2. Documented behavior

   Public flow documentation expressly allows the SSP to reject a previously quoted static-deposit claim, while public wallet code routes default Lightning and cooperative-exit requests through the configured SSP. 456789

   Supporting material shown on this page

   documented SSP rejection pointPinned source code · github.com · checked 2026-07-14

   29    Alice->>SSP: quote for UTXO
   30    SSP-->>Alice: quote<id, utxo, credit_amount, signed: ssp_id_key>
   31    Note right of Alice: utxo is <transaction_id, output_index, network>
   32
   33    Alice->>SSP: ClaimStaticDeposit <utxo, credit_amount_sats, deposit_secret_key, user_signature>
   34    Note right of SSP: SSP does not commit to a quote and can reject any previously provided quotes
   35    SSP->>SSP: create transfer to Alice and tweak the keys

   default Lightning SSP flowPinned source code · github.com · checked 2026-07-14

   4222          // Advance local state — leaves are now locked on the SO
   4223          await this.leafManager.handleTransferEvent(swapResponse.transfer);
   4224
   4225          const sspResponse = await sspClient.requestLightningSend({
   4226            encodedInvoice: invoice,
   4227            amountSats: isZeroAmountInvoice ? amountSatsToSend! : undefined,

   default cooperative-exit flowPinned source code · github.com · checked 2026-07-14

   5037          path: leaf.id,
   5038        },
   5039        newKeyDerivation: {
   5040          type: KeyDerivationType.RANDOM,
   5041        },
   5042        receiverIdentityPublicKey: sspPubKey,
   5043      }));

   Breez SSP configurationPinned source code · github.com · checked 2026-07-14

   54            Network::Mainnet => Self {
   55                network,
   56                operator_pool: Self::default_operator_pool_config(network),
   57                reconnect_interval_seconds: 1,
   58                service_provider_config: Self::create_service_provider_config(
   59                    "https://api.lightspark.com",
   60                    "023e33e2920326f64ea31058d44777442d97d7d5cbfcf54e3060bc1695e5261c93",

   Breez Lightning SSP flowPinned source code · github.com · checked 2026-07-14

   665            return Ok((to_pay_sat, Some(receiver_address)));
   666        }
   667
   668        let fee_estimate = self
   669            .ssp_client
   670            .get_lightning_send_fee_estimate(invoice, Some(to_pay_sat))
   671            .await?;

   Breez cooperative-exit SSP flowPinned source code · github.com · checked 2026-07-14

   149        withdrawal_address: Address,
   150    ) -> Result<CoopExitFeeQuote, ServiceError> {
   151        let leaf_external_ids: Vec<String> =
   152            leaves.iter().map(|leaf| leaf.id.to_string()).collect();
   153
   154        self.ssp_client
   155            .get_coop_exit_fee_quote(leaf_external_ids, &withdrawal_address.to_string())

Scope control

What this does not establish

• Public inaccessibility does not establish why the implementation is private, what policies it contains, or that sanctions screening is deployed there. Lightspark's open-source statement concerns Spark and does not expressly promise an open-source SSP. 1310

Sources and excerpts

Primary sources

The relevant details and available source-code excerpts appear alongside the claims above. This list preserves the complete original-source trail for independent verification.