Phase 5: Lightning auto-payout with LNURL-pay and NUT-05 melt

- New lnurl_pay.c/h: LNURL-pay protocol (GET .well-known/lnurlp + callback)
- New lightning_payout.c/h: threshold-based auto-payout with multi-recipient split
- Extended nucula_wallet bridge with nucula_wallet_melt() (NUT-05)
- Config: payout section with multi-mint, multi-recipient, fee_tolerance
- Default: enabled, TollGate@coinos.io, min_payout=128, min_balance=64
- 18 new unit tests (all passing), 134 total

20 files changed, 669 insertions, 19 deletions

diff --git a/CHECKLIST.md b/CHECKLIST.md
index dd21b0c..5cedd30 100644
--- a/CHECKLIST.md
+++ b/CHECKLIST.md
@@ -192,29 +192,29 @@
 ## Phase 4: ESP32 TollGate Client Detection + Auto-Payment — IN PROGRESS
 
 ### tollgate_client.c/h (New)
-- [ ] Create `tollgate_client.h` — types: `tollgate_discovery_t`, `tollgate_client_state_t` enum (IDLE/DETECTING/NEEDS_PAY/PAYING/PAID/RENEWING)
-- [ ] Create `tollgate_client.c` — detection, payment, monitoring, state machine
-- [ ] `tollgate_client_detect(gw_ip)` — HTTP GET `http://{gw}:2121/`, parse kind=10021, extract price tags
-- [ ] `tollgate_client_pay(gw_ip, amount_sats)` — `nucula_wallet_send()` → POST to upstream → parse kind=1022/21023
-- [ ] `tollgate_client_on_sta_connected()` — extract gw from DHCP, detect, pay (blocking)
-- [ ] `tollgate_client_tick()` — GET `/usage`, renew at 20% remaining
-- [ ] `tollgate_client_on_sta_disconnected()` — reset state
-- [ ] `tollgate_client_get_usage(gw_ip)` — GET `/usage` → parse remaining/total
+- [x] Create `tollgate_client.h` — types: `tollgate_discovery_t`, `tollgate_client_state_t` enum (IDLE/DETECTING/NEEDS_PAY/PAYING/PAID/RENEWING)
+- [x] Create `tollgate_client.c` — detection, payment, monitoring, state machine
+- [x] `tollgate_client_detect(gw_ip)` — HTTP GET `http://{gw}:2121/`, parse kind=10021, extract price tags
+- [x] `tollgate_client_pay(gw_ip, amount_sats)` — `nucula_wallet_send()` → POST to upstream → parse kind=1022/21023
+- [x] `tollgate_client_on_sta_connected()` — extract gw from DHCP, detect, pay (blocking)
+- [x] `tollgate_client_tick()` — GET `/usage`, renew at 20% remaining
+- [x] `tollgate_client_on_sta_disconnected()` — reset state
+- [x] `tollgate_client_get_usage(gw_ip)` — GET `/usage` → parse remaining/total
 
 ### Config Changes
-- [ ] Add to `config.h`: `client_enabled`, `client_steps_to_buy`, `client_renewal_threshold_pct`, `client_retry_interval_ms`
-- [ ] Parse new fields in `config.c`
+- [x] Add to `config.h`: `client_enabled`, `client_steps_to_buy`, `client_renewal_threshold_pct`, `client_retry_interval_ms`
+- [x] Parse new fields in `config.c`
 
 ### Integration (tollgate_main.c)
-- [ ] Make wallet init synchronous (call `nucula_wallet_init()` directly, not as task)
-- [ ] Add `tollgate_client_on_sta_connected()` in `ip_event_handler` (blocking, before `start_services()`)
-- [ ] Add `tollgate_client_on_sta_disconnected()` in `wifi_event_handler`
-- [ ] Add `tollgate_client_tick()` in main loop
-- [ ] Update `main/CMakeLists.txt` — add `tollgate_client.c`
+- [x] Make wallet init synchronous (call `nucula_wallet_init()` directly, not as task)
+- [x] Add `tollgate_client_on_sta_connected()` in `ip_event_handler` (blocking, before `start_services()`)
+- [x] Add `tollgate_client_on_sta_disconnected()` in `wifi_event_handler`
+- [x] Add `tollgate_client_tick()` in main loop
+- [x] Update `main/CMakeLists.txt` — add `tollgate_client.c`
 
 ### Unit Tests
-- [ ] `tests/unit/test_tollgate_client.c` — discovery parsing, price extraction, state machine, renewal threshold
-- [ ] All unit tests passing
+- [x] `tests/unit/test_tollgate_client.c` — discovery parsing, price extraction, state machine, renewal threshold
+- [x] All unit tests passing (30 new, 116 total) — committed at `78dd599`
 
 ### Integration Tests
 - [ ] ESP32→OpenWRT auto-payment (Scenario 4)
diff --git a/components/nucula_lib/nucula_wallet.cpp b/components/nucula_lib/nucula_wallet.cpp
index 50583f9..9a24e89 100644
--- a/components/nucula_lib/nucula_wallet.cpp
+++ b/components/nucula_lib/nucula_wallet.cpp
@@ -197,3 +197,38 @@ void nucula_wallet_print_status(void)
                  proofs[i].amount, proofs[i].id.c_str());
     }
 }
+
+esp_err_t nucula_wallet_melt(const char *bolt11_invoice, uint64_t max_fee_sats)
+{
+    if (!s_wallet || !bolt11_invoice) return ESP_FAIL;
+
+    cashu::MeltQuote quote;
+    if (!s_wallet->request_melt_quote(std::string(bolt11_invoice), quote)) {
+        ESP_LOGE(TAG, "Melt quote request failed");
+        return ESP_FAIL;
+    }
+
+    uint64_t total_cost = (uint64_t)quote.amount + (uint64_t)quote.fee_reserve;
+    if (total_cost > max_fee_sats) {
+        ESP_LOGE(TAG, "Melt cost %llu exceeds max %llu (amount=%d fee=%d)",
+                 (unsigned long long)total_cost, (unsigned long long)max_fee_sats,
+                 quote.amount, quote.fee_reserve);
+        return ESP_FAIL;
+    }
+
+    int balance_before = s_wallet->balance();
+    if (balance_before < quote.amount) {
+        ESP_LOGE(TAG, "Insufficient balance: %d < %d", balance_before, quote.amount);
+        return ESP_FAIL;
+    }
+
+    int change_amount = 0;
+    if (!s_wallet->melt_tokens(quote, change_amount)) {
+        ESP_LOGE(TAG, "Melt tokens failed");
+        return ESP_FAIL;
+    }
+
+    ESP_LOGI(TAG, "Melted: %d sats paid, %d change, balance=%d->%d",
+             quote.amount, change_amount, balance_before, s_wallet->balance());
+    return ESP_OK;
+}
diff --git a/components/nucula_lib/nucula_wallet.h b/components/nucula_lib/nucula_wallet.h
index 64b7c24..784a126 100644
--- a/components/nucula_lib/nucula_wallet.h
+++ b/components/nucula_lib/nucula_wallet.h
@@ -22,6 +22,8 @@ char *nucula_wallet_proofs_json(void);
 
 esp_err_t nucula_wallet_swap_all(void);
 
+esp_err_t nucula_wallet_melt(const char *bolt11_invoice, uint64_t max_fee_sats);
+
 void nucula_wallet_print_status(void);
 
 #ifdef __cplusplus
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index be4d564..c2aaeb2 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -11,6 +11,8 @@ idf_component_register(SRCS "tollgate_main.c"
                             "geohash.c"
                             "wifistr.c"
                             "tollgate_client.c"
+                            "lnurl_pay.c"
+                            "lightning_payout.c"
                     INCLUDE_DIRS "."
                     REQUIRES esp_wifi esp_event esp_netif nvs_flash esp_http_server
                              lwip json esp_http_client mbedtls esp-tls log spiffs
diff --git a/main/config.c b/main/config.c
index c074410..9257397 100644
--- a/main/config.c
+++ b/main/config.c
@@ -26,6 +26,11 @@ esp_err_t tollgate_config_init(void)
     g_config.client_steps_to_buy = 1;
     g_config.client_renewal_threshold_pct = 20;
     g_config.client_retry_interval_ms = 30000;
+    g_config.payout.enabled = true;
+    g_config.payout.fee_tolerance_pct = 10;
+    g_config.payout.check_interval_s = 60;
+    g_config.payout.recipient_count = 0;
+    g_config.payout.mint_count = 0;
 
     esp_vfs_spiffs_conf_t conf = {
         .base_path = "/spiffs",
@@ -166,6 +171,75 @@ esp_err_t tollgate_config_init(void)
     cJSON *client_retry = cJSON_GetObjectItem(root, "client_retry_interval_ms");
     if (client_retry) g_config.client_retry_interval_ms = client_retry->valueint;
 
+    cJSON *payout = cJSON_GetObjectItem(root, "payout");
+    if (payout && cJSON_IsObject(payout)) {
+        cJSON *p_en = cJSON_GetObjectItem(payout, "enabled");
+        if (p_en && cJSON_IsBool(p_en)) g_config.payout.enabled = cJSON_IsTrue(p_en);
+
+        cJSON *p_fee = cJSON_GetObjectItem(payout, "fee_tolerance_pct");
+        if (p_fee) g_config.payout.fee_tolerance_pct = (uint64_t)p_fee->valuedouble;
+
+        cJSON *p_interval = cJSON_GetObjectItem(payout, "check_interval_s");
+        if (p_interval) g_config.payout.check_interval_s = p_interval->valueint;
+
+        cJSON *recipients = cJSON_GetObjectItem(payout, "recipients");
+        if (recipients && cJSON_IsArray(recipients)) {
+            int rcount = cJSON_GetArraySize(recipients);
+            if (rcount > PAYOUT_MAX_RECIPIENTS) rcount = PAYOUT_MAX_RECIPIENTS;
+            for (int i = 0; i < rcount; i++) {
+                cJSON *r = cJSON_GetArrayItem(recipients, i);
+                cJSON *addr = cJSON_GetObjectItem(r, "lightning_address");
+                cJSON *factor = cJSON_GetObjectItem(r, "factor");
+                if (addr && cJSON_IsString(addr)) {
+                    strncpy(g_config.payout.recipients[i].lightning_address, addr->valuestring,
+                            sizeof(g_config.payout.recipients[i].lightning_address) - 1);
+                }
+                if (factor && cJSON_IsNumber(factor)) {
+                    g_config.payout.recipients[i].factor = factor->valuedouble;
+                }
+            }
+            g_config.payout.recipient_count = rcount;
+        }
+
+        cJSON *mints = cJSON_GetObjectItem(payout, "mints");
+        if (mints && cJSON_IsArray(mints)) {
+            int mcount = cJSON_GetArraySize(mints);
+            if (mcount > PAYOUT_MAX_MINTS) mcount = PAYOUT_MAX_MINTS;
+            for (int i = 0; i < mcount; i++) {
+                cJSON *m = cJSON_GetArrayItem(mints, i);
+                cJSON *murl = cJSON_GetObjectItem(m, "url");
+                cJSON *mbal = cJSON_GetObjectItem(m, "min_balance");
+                cJSON *mpay = cJSON_GetObjectItem(m, "min_payout_amount");
+                if (murl && cJSON_IsString(murl)) {
+                    strncpy(g_config.payout.mints[i].url, murl->valuestring,
+                            sizeof(g_config.payout.mints[i].url) - 1);
+                }
+                if (mbal && cJSON_IsNumber(mbal)) {
+                    g_config.payout.mints[i].min_balance = (uint64_t)mbal->valuedouble;
+                }
+                if (mpay && cJSON_IsNumber(mpay)) {
+                    g_config.payout.mints[i].min_payout_amount = (uint64_t)mpay->valuedouble;
+                }
+            }
+            g_config.payout.mint_count = mcount;
+        }
+    }
+
+    if (g_config.payout.mint_count == 0 && g_config.mint_url[0] != '\0') {
+        strncpy(g_config.payout.mints[0].url, g_config.mint_url,
+                sizeof(g_config.payout.mints[0].url) - 1);
+        g_config.payout.mints[0].min_balance = 64;
+        g_config.payout.mints[0].min_payout_amount = 128;
+        g_config.payout.mint_count = 1;
+    }
+
+    if (g_config.payout.recipient_count == 0) {
+        strncpy(g_config.payout.recipients[0].lightning_address, "TollGate@coinos.io",
+                sizeof(g_config.payout.recipients[0].lightning_address) - 1);
+        g_config.payout.recipients[0].factor = 1.0;
+        g_config.payout.recipient_count = 1;
+    }
+
     cJSON_Delete(root);
 
     if (g_config.nostr_relay_count == 0) {
diff --git a/main/config.h b/main/config.h
index 4c6116e..de9f856 100644
--- a/main/config.h
+++ b/main/config.h
@@ -6,6 +6,8 @@
 #include "esp_netif.h"
 #include <stdbool.h>
 
+#include "lightning_payout.h"
+
 #define TOLLGATE_MAX_WIFI_NETWORKS 5
 #define TOLLGATE_MAX_MINT_URLS     3
 #define TOLLGATE_MAX_AP_SSID_LEN   32
@@ -54,6 +56,8 @@ typedef struct {
     int client_steps_to_buy;
     int client_renewal_threshold_pct;
     int client_retry_interval_ms;
+
+    payout_config_t payout;
 } tollgate_config_t;
 
 void tollgate_config_derive_unique(tollgate_config_t *cfg);
diff --git a/main/lightning_payout.c b/main/lightning_payout.c
new file mode 100644
index 0000000..42593a9
--- /dev/null
+++ b/main/lightning_payout.c
@@ -0,0 +1,93 @@
+#include "lightning_payout.h"
+#include "lnurl_pay.h"
+#include "nucula_wallet.h"
+#include "esp_log.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include <string.h>
+#include <math.h>
+
+static const char *TAG = "ln_payout";
+
+static payout_config_t s_config;
+static int64_t s_last_check_ms = 0;
+
+static int64_t get_time_ms(void) {
+    return (int64_t)(xTaskGetTickCount() * portTICK_PERIOD_MS);
+}
+
+esp_err_t lightning_payout_init(const payout_config_t *config)
+{
+    if (!config) return ESP_FAIL;
+    memcpy(&s_config, config, sizeof(s_config));
+    s_last_check_ms = get_time_ms();
+    ESP_LOGI(TAG, "Payout initialized: %d mints, %d recipients, interval=%ds",
+             s_config.mint_count, s_config.recipient_count, s_config.check_interval_s);
+    return ESP_OK;
+}
+
+static esp_err_t payout_one(const char *lightning_address, uint64_t amount_sats, uint64_t fee_tolerance_pct)
+{
+    if (amount_sats == 0) return ESP_OK;
+
+    char bolt11[LNURL_MAX_BOLT11_LEN];
+    esp_err_t err = lnurl_get_invoice(lightning_address, amount_sats, bolt11, sizeof(bolt11));
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "Failed to get invoice for %s (%llu sats)", lightning_address, (unsigned long long)amount_sats);
+        return err;
+    }
+
+    uint64_t max_cost = amount_sats + (amount_sats * fee_tolerance_pct / 100);
+    err = nucula_wallet_melt(bolt11, max_cost);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "Melt failed for %s", lightning_address);
+        return err;
+    }
+
+    ESP_LOGI(TAG, "Payout: %llu sats -> %s", (unsigned long long)amount_sats, lightning_address);
+    return ESP_OK;
+}
+
+void lightning_payout_tick(void)
+{
+    if (!s_config.enabled) return;
+    if (s_config.recipient_count == 0) return;
+
+    int64_t now = get_time_ms();
+    int64_t elapsed = now - s_last_check_ms;
+    int64_t interval_ms = (int64_t)s_config.check_interval_s * 1000;
+    if (elapsed < interval_ms) return;
+
+    s_last_check_ms = now;
+
+    uint64_t balance = nucula_wallet_balance();
+
+    for (int m = 0; m < s_config.mint_count; m++) {
+        const payout_mint_config_t *mc = &s_config.mints[m];
+
+        if (balance < mc->min_payout_amount) {
+            ESP_LOGI(TAG, "Balance %llu < min_payout %llu for %s, skipping",
+                     (unsigned long long)balance, (unsigned long long)mc->min_payout_amount, mc->url);
+            continue;
+        }
+
+        uint64_t payout_pool = balance - mc->min_balance;
+        if (payout_pool == 0) continue;
+
+        ESP_LOGI(TAG, "Payout pool: %llu sats (balance=%llu - reserve=%llu)",
+                 (unsigned long long)payout_pool, (unsigned long long)balance,
+                 (unsigned long long)mc->min_balance);
+
+        for (int r = 0; r < s_config.recipient_count; r++) {
+            const payout_recipient_t *recip = &s_config.recipients[r];
+            if (recip->factor <= 0.0 || recip->lightning_address[0] == '\0') continue;
+
+            uint64_t share = (uint64_t)round((double)payout_pool * recip->factor);
+            if (share == 0) continue;
+
+            payout_one(recip->lightning_address, share, s_config.fee_tolerance_pct);
+        }
+
+        balance = nucula_wallet_balance();
+    }
+}
diff --git a/main/lightning_payout.h b/main/lightning_payout.h
new file mode 100644
index 0000000..d353902
--- /dev/null
+++ b/main/lightning_payout.h
@@ -0,0 +1,37 @@
+#ifndef LIGHTNING_PAYOUT_H
+#define LIGHTNING_PAYOUT_H
+
+#include "esp_err.h"
+#include <stdint.h>
+#include <stdbool.h>
+
+#define PAYOUT_MAX_RECIPIENTS     4
+#define PAYOUT_MAX_MINTS          3
+#define PAYOUT_MAX_ADDR_LEN       128
+
+typedef struct {
+    char lightning_address[PAYOUT_MAX_ADDR_LEN];
+    double factor;
+} payout_recipient_t;
+
+typedef struct {
+    char url[256];
+    uint64_t min_balance;
+    uint64_t min_payout_amount;
+} payout_mint_config_t;
+
+typedef struct {
+    bool enabled;
+    payout_mint_config_t mints[PAYOUT_MAX_MINTS];
+    int mint_count;
+    payout_recipient_t recipients[PAYOUT_MAX_RECIPIENTS];
+    int recipient_count;
+    uint64_t fee_tolerance_pct;
+    int check_interval_s;
+} payout_config_t;
+
+esp_err_t lightning_payout_init(const payout_config_t *config);
+
+void lightning_payout_tick(void);
+
+#endif
diff --git a/main/lnurl_pay.c b/main/lnurl_pay.c
new file mode 100644
index 0000000..bf3a932
--- /dev/null
+++ b/main/lnurl_pay.c
@@ -0,0 +1,156 @@
+#include "lnurl_pay.h"
+#include "esp_log.h"
+#include "esp_http_client.h"
+#include "esp_crt_bundle.h"
+#include "cJSON.h"
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+static const char *TAG = "lnurl_pay";
+
+static esp_err_t http_get_json(const char *url, char *resp_buf, size_t resp_buf_size, int *status_out)
+{
+    esp_http_client_config_t config = {
+        .url = url,
+        .method = HTTP_METHOD_GET,
+        .timeout_ms = 15000,
+        .crt_bundle_attach = esp_crt_bundle_attach,
+    };
+    esp_http_client_handle_t client = esp_http_client_init(&config);
+    if (!client) return ESP_FAIL;
+
+    esp_err_t err = esp_http_client_open(client, 0);
+    if (err != ESP_OK) {
+        esp_http_client_cleanup(client);
+        return ESP_FAIL;
+    }
+
+    int content_length = esp_http_client_fetch_headers(client);
+    (void)content_length;
+    int status = esp_http_client_get_status_code(client);
+    if (status_out) *status_out = status;
+
+    int resp_len = esp_http_client_read(client, resp_buf, resp_buf_size - 1);
+    esp_http_client_cleanup(client);
+
+    if (resp_len < 0) return ESP_FAIL;
+    resp_buf[resp_len] = '\0';
+    return ESP_OK;
+}
+
+esp_err_t lnurl_get_invoice(const char *lightning_address, uint64_t amount_sats,
+                            char *bolt11_out, size_t bolt11_out_size)
+{
+    if (!lightning_address || !bolt11_out) return ESP_FAIL;
+
+    const char *at = strchr(lightning_address, '@');
+    if (!at) {
+        ESP_LOGE(TAG, "Invalid lightning address: missing '@'");
+        return ESP_FAIL;
+    }
+
+    size_t user_len = at - lightning_address;
+    char username[64];
+    if (user_len >= sizeof(username)) return ESP_FAIL;
+    memcpy(username, lightning_address, user_len);
+    username[user_len] = '\0';
+
+    const char *domain = at + 1;
+
+    char url[512];
+    snprintf(url, sizeof(url), "https://%s/.well-known/lnurlp/%s", domain, username);
+
+    ESP_LOGI(TAG, "LNURL-pay step 1: GET %s", url);
+
+    char *resp_buf = malloc(4096);
+    if (!resp_buf) return ESP_ERR_NO_MEM;
+
+    int status = 0;
+    esp_err_t err = http_get_json(url, resp_buf, 4096, &status);
+    if (err != ESP_OK || status != 200) {
+        ESP_LOGE(TAG, "LNURL-pay step 1 failed: status=%d err=%s", status, esp_err_to_name(err));
+        free(resp_buf);
+        return ESP_FAIL;
+    }
+
+    cJSON *root = cJSON_Parse(resp_buf);
+    if (!root) {
+        ESP_LOGE(TAG, "LNURL-pay step 1: invalid JSON");
+        free(resp_buf);
+        return ESP_FAIL;
+    }
+
+    cJSON *callback = cJSON_GetObjectItemCaseSensitive(root, "callback");
+    if (!callback || !cJSON_IsString(callback)) {
+        ESP_LOGE(TAG, "LNURL-pay step 1: missing callback");
+        cJSON_Delete(root);
+        free(resp_buf);
+        return ESP_FAIL;
+    }
+
+    char callback_url[512];
+    strncpy(callback_url, callback->valuestring, sizeof(callback_url) - 1);
+
+    cJSON *min_sendable = cJSON_GetObjectItemCaseSensitive(root, "minSendable");
+    cJSON *max_sendable = cJSON_GetObjectItemCaseSensitive(root, "maxSendable");
+
+    uint64_t amount_msat = amount_sats * 1000;
+    if (min_sendable && cJSON_IsNumber(min_sendable) && amount_msat < (uint64_t)min_sendable->valuedouble) {
+        ESP_LOGE(TAG, "Amount %llumsat below min %g", (unsigned long long)amount_msat, min_sendable->valuedouble);
+        cJSON_Delete(root);
+        free(resp_buf);
+        return ESP_FAIL;
+    }
+    if (max_sendable && cJSON_IsNumber(max_sendable) && amount_msat > (uint64_t)max_sendable->valuedouble) {
+        ESP_LOGE(TAG, "Amount %llumsat above max %g", (unsigned long long)amount_msat, max_sendable->valuedouble);
+        cJSON_Delete(root);
+        free(resp_buf);
+        return ESP_FAIL;
+    }
+
+    cJSON_Delete(root);
+
+    char callback_with_amount[768];
+    snprintf(callback_with_amount, sizeof(callback_with_amount), "%s%samount=%llu",
+             callback_url, strchr(callback_url, '?') ? "&" : "?",
+             (unsigned long long)amount_msat);
+
+    free(resp_buf);
+
+    ESP_LOGI(TAG, "LNURL-pay step 2: GET %s", callback_with_amount);
+
+    resp_buf = malloc(4096);
+    if (!resp_buf) return ESP_ERR_NO_MEM;
+
+    err = http_get_json(callback_with_amount, resp_buf, 4096, &status);
+    if (err != ESP_OK || status != 200) {
+        ESP_LOGE(TAG, "LNURL-pay step 2 failed: status=%d", status);
+        free(resp_buf);
+        return ESP_FAIL;
+    }
+
+    root = cJSON_Parse(resp_buf);
+    free(resp_buf);
+    if (!root) return ESP_FAIL;
+
+    cJSON *pr = cJSON_GetObjectItemCaseSensitive(root, "pr");
+    if (!pr || !cJSON_IsString(pr)) {
+        ESP_LOGE(TAG, "LNURL-pay step 2: missing 'pr' (bolt11)");
+        cJSON_Delete(root);
+        return ESP_FAIL;
+    }
+
+    size_t pr_len = strlen(pr->valuestring);
+    if (pr_len >= bolt11_out_size) {
+        ESP_LOGE(TAG, "BOLT11 too long: %zu >= %zu", pr_len, bolt11_out_size);
+        cJSON_Delete(root);
+        return ESP_FAIL;
+    }
+
+    memcpy(bolt11_out, pr->valuestring, pr_len + 1);
+    cJSON_Delete(root);
+
+    ESP_LOGI(TAG, "Got BOLT11 invoice (%zu bytes) for %llu sats", pr_len, (unsigned long long)amount_sats);
+    return ESP_OK;
+}
diff --git a/main/lnurl_pay.h b/main/lnurl_pay.h
new file mode 100644
index 0000000..8969e38
--- /dev/null
+++ b/main/lnurl_pay.h
@@ -0,0 +1,14 @@
+#ifndef LNURL_PAY_H
+#define LNURL_PAY_H
+
+#include "esp_err.h"
+#include <stdint.h>
+#include <stddef.h>
+
+#define LNURL_MAX_BOLT11_LEN 2048
+#define LNURL_MAX_ADDR_LEN   128
+
+esp_err_t lnurl_get_invoice(const char *lightning_address, uint64_t amount_sats,
+                            char *bolt11_out, size_t bolt11_out_size);
+
+#endif
diff --git a/main/tollgate_main.c b/main/tollgate_main.c
index d4dcf0d..3f83923 100644
--- a/main/tollgate_main.c
+++ b/main/tollgate_main.c
@@ -20,6 +20,7 @@
 #include "nucula_wallet.h"
 #include "wifistr.h"
 #include "tollgate_client.h"
+#include "lightning_payout.h"
 
 #define MAX_STA_RETRY 5
 static const char *TAG = "tollgate_main";
@@ -89,6 +90,8 @@ static void ip_event_handler(void *arg, esp_event_base_t event_base,
         const tollgate_config_t *cfg = tollgate_config_get();
         nucula_wallet_init(cfg->mint_url);
 
+        lightning_payout_init(&cfg->payout);
+
         char gw_ip_str[16];
         snprintf(gw_ip_str, sizeof(gw_ip_str), IPSTR, IP2STR(&event->ip_info.gw));
         tollgate_client_on_sta_connected(gw_ip_str);
@@ -282,5 +285,6 @@ void app_main(void)
         vTaskDelay(pdMS_TO_TICKS(1000));
         session_tick();
         tollgate_client_tick();
+        lightning_payout_tick();
     }
 }
diff --git a/tests/unit/Makefile b/tests/unit/Makefile
index e4ea388..f31172b 100644
--- a/tests/unit/Makefile
+++ b/tests/unit/Makefile
@@ -17,11 +17,11 @@ CFLAGS := -Wall -Wextra -Wno-unused-parameter -Wno-unused-function -Wno-sign-com
           -I $(SECP256K1_CFG) \
           -I /usr/include/cjson
 
-LDFLAGS := -lmbedcrypto -lcjson
+LDFLAGS := -lmbedcrypto -lcjson -lm
 
 SECP256K1_OBJ := secp256k1.o precomputed_ecmult.o precomputed_ecmult_gen.o
 
-TESTS := test_geohash test_identity test_nostr_event test_cashu test_session test_tollgate_client
+TESTS := test_geohash test_identity test_nostr_event test_cashu test_session test_tollgate_client test_lnurl_pay test_lightning_payout
 
 .PHONY: all test clean $(TESTS)
 
@@ -65,5 +65,11 @@ test_session: test_session.c $(REPO_ROOT)/main/session.c
 test_tollgate_client: test_tollgate_client.c
         $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 
+test_lnurl_pay: test_lnurl_pay.c
+        $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
+
+test_lightning_payout: test_lightning_payout.c
+        $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
+
 clean:
         rm -f $(TESTS) $(SECP256K1_OBJ)
diff --git a/tests/unit/stubs/nucula_wallet.h b/tests/unit/stubs/nucula_wallet.h
index 260ec35..399b3b5 100644
--- a/tests/unit/stubs/nucula_wallet.h
+++ b/tests/unit/stubs/nucula_wallet.h
@@ -12,6 +12,7 @@ uint64_t nucula_wallet_balance(void);
 int nucula_wallet_proof_count(void);
 char *nucula_wallet_proofs_json(void);
 esp_err_t nucula_wallet_swap_all(void);
+esp_err_t nucula_wallet_melt(const char *bolt11_invoice, uint64_t max_fee_sats);
 void nucula_wallet_print_status(void);
 
 #endif
diff --git a/tests/unit/test_geohash b/tests/unit/test_geohash
index db87d33..dc5045f 100755
--- a/tests/unit/test_geohash
+++ b/tests/unit/test_geohash
diff --git a/tests/unit/test_identity b/tests/unit/test_identity
index c89de17..7ad1485 100755
--- a/tests/unit/test_identity
+++ b/tests/unit/test_identity
diff --git a/tests/unit/test_lightning_payout b/tests/unit/test_lightning_payout
new file mode 100755
index 0000000..b10888c
--- /dev/null
+++ b/tests/unit/test_lightning_payout
diff --git a/tests/unit/test_lightning_payout.c b/tests/unit/test_lightning_payout.c
new file mode 100644
index 0000000..8501eb9
--- /dev/null
+++ b/tests/unit/test_lightning_payout.c
@@ -0,0 +1,97 @@
+#include "test_framework.h"
+#include "../../main/lightning_payout.h"
+#include "../../main/config.h"
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+
+static void test_payout_calculation(void)
+{
+    printf("\n--- Payout pool calculation ---\n");
+    {
+        uint64_t balance = 500;
+        uint64_t min_balance = 64;
+        uint64_t min_payout_amount = 128;
+
+        ASSERT(balance >= min_payout_amount, "500 >= 128 triggers payout");
+
+        uint64_t pool = balance - min_balance;
+        ASSERT_EQ_INT(436, (int)pool, "pool = 500 - 64 = 436");
+    }
+
+    printf("\n--- Payout below threshold ---\n");
+    {
+        uint64_t balance = 100;
+        uint64_t min_payout_amount = 128;
+
+        ASSERT(balance < min_payout_amount, "100 < 128, no payout");
+    }
+
+    printf("\n--- Multi-recipient split ---\n");
+    {
+        uint64_t pool = 436;
+        double factors[] = {0.79, 0.21};
+        const char *names[] = {"owner", "developer"};
+
+        uint64_t total = 0;
+        for (int i = 0; i < 2; i++) {
+            uint64_t share = (uint64_t)round((double)pool * factors[i]);
+            printf("  %s: factor=%.2f share=%llu\n", names[i], factors[i], (unsigned long long)share);
+            total += share;
+        }
+        ASSERT_EQ_INT(436, (int)total, "79/21 split sums to pool");
+    }
+
+    printf("\n--- Single recipient 100%% ---\n");
+    {
+        uint64_t pool = 436;
+        double factor = 1.0;
+        uint64_t share = (uint64_t)round((double)pool * factor);
+        ASSERT_EQ_INT(436, (int)share, "1.0 factor = full pool");
+    }
+
+    printf("\n--- Fee tolerance calculation ---\n");
+    {
+        uint64_t share = 344;
+        uint64_t fee_pct = 10;
+        uint64_t max_cost = share + (share * fee_pct / 100);
+        ASSERT_EQ_INT(378, (int)max_cost, "344 + 10% = 378");
+    }
+
+    printf("\n--- Zero pool (balance == reserve) ---\n");
+    {
+        uint64_t balance = 64;
+        uint64_t min_balance = 64;
+        uint64_t pool = balance - min_balance;
+        ASSERT_EQ_INT(0, (int)pool, "no payout when balance == reserve");
+    }
+
+    printf("\n--- Payout config defaults ---\n");
+    {
+        payout_config_t cfg;
+        memset(&cfg, 0, sizeof(cfg));
+        cfg.enabled = true;
+        cfg.mint_count = 1;
+        strncpy(cfg.mints[0].url, "https://testnut.cashu.space", sizeof(cfg.mints[0].url) - 1);
+        cfg.mints[0].min_balance = 64;
+        cfg.mints[0].min_payout_amount = 128;
+        cfg.recipient_count = 1;
+        strncpy(cfg.recipients[0].lightning_address, "TollGate@coinos.io",
+                sizeof(cfg.recipients[0].lightning_address) - 1);
+        cfg.recipients[0].factor = 1.0;
+        cfg.fee_tolerance_pct = 10;
+        cfg.check_interval_s = 60;
+
+        ASSERT(cfg.enabled, "payout enabled");
+        ASSERT_EQ_INT(1, cfg.mint_count, "1 mint");
+        ASSERT_EQ_INT(1, cfg.recipient_count, "1 recipient");
+        ASSERT_EQ_STR("TollGate@coinos.io", cfg.recipients[0].lightning_address, "default LNURL");
+    }
+}
+
+int main(void)
+{
+    printf("=== test_lightning_payout ===\n");
+    test_payout_calculation();
+    TEST_SUMMARY();
+}
diff --git a/tests/unit/test_lnurl_pay b/tests/unit/test_lnurl_pay
new file mode 100755
index 0000000..1f16293
--- /dev/null
+++ b/tests/unit/test_lnurl_pay
diff --git a/tests/unit/test_lnurl_pay.c b/tests/unit/test_lnurl_pay.c
new file mode 100644
index 0000000..d630b9c
--- /dev/null
+++ b/tests/unit/test_lnurl_pay.c
@@ -0,0 +1,125 @@
+#include "test_framework.h"
+#include <cjson/cJSON.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+static const char *SAMPLE_LNURLP_RESPONSE =
+    "{\"callback\":\"https://coinos.io/lnurlp/callback/abc123\","
+    "\"maxSendable\":1000000000,"
+    "\"minSendable\":1000,"
+    "\"metadata\":\"[[\\\"text/identifier\\\",\\\"TollGate@coinos.io\\\"]]\","
+    "\"tag\":\"payRequest\"}";
+
+static const char *SAMPLE_CALLBACK_RESPONSE =
+    "{\"pr\":\"lnbc1pvjluezpp5qqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqqqsyqcyq5rqwzqfqypqhp58yjmdan7s4g2e65tr58a50k2jdhz3l8eqc5x5z5f9e3u70fxnh00x09ml0q CONSTANTS\"}";
+
+static const char *SAMPLE_MISSING_AT = "no-at-sign.com";
+static const char *SAMPLE_MISSING_CALLBACK = "{\"tag\":\"payRequest\"}";
+static const char *SAMPLE_MISSING_PR = "{\"status\":\"ERROR\"}";
+
+static bool test_parse_lnurlp_response(void)
+{
+    cJSON *root = cJSON_Parse(SAMPLE_LNURLP_RESPONSE);
+    if (!root) return false;
+
+    cJSON *callback = cJSON_GetObjectItemCaseSensitive(root, "callback");
+    bool ok = (callback && cJSON_IsString(callback) &&
+               strcmp(callback->valuestring, "https://coinos.io/lnurlp/callback/abc123") == 0);
+
+    cJSON *min_sendable = cJSON_GetObjectItemCaseSensitive(root, "minSendable");
+    ok = ok && (min_sendable && cJSON_IsNumber(min_sendable) && min_sendable->valuedouble == 1000);
+
+    cJSON *max_sendable = cJSON_GetObjectItemCaseSensitive(root, "maxSendable");
+    ok = ok && (max_sendable && cJSON_IsNumber(max_sendable));
+
+    cJSON_Delete(root);
+    return ok;
+}
+
+static bool test_parse_callback_response(void)
+{
+    cJSON *root = cJSON_Parse(SAMPLE_CALLBACK_RESPONSE);
+    if (!root) return false;
+
+    cJSON *pr = cJSON_GetObjectItemCaseSensitive(root, "pr");
+    bool ok = (pr && cJSON_IsString(pr) && strncmp(pr->valuestring, "lnbc", 4) == 0);
+
+    cJSON_Delete(root);
+    return ok;
+}
+
+static bool test_lightning_address_parse(void)
+{
+    const char *addr = "TollGate@coinos.io";
+    const char *at = strchr(addr, '@');
+    if (!at) return false;
+
+    size_t user_len = at - addr;
+    if (user_len != 8) return false;
+
+    char username[64];
+    memcpy(username, addr, user_len);
+    username[user_len] = '\0';
+
+    if (strcmp(username, "TollGate") != 0) return false;
+    if (strcmp(at + 1, "coinos.io") != 0) return false;
+
+    return true;
+}
+
+static bool test_amount_validation(void)
+{
+    uint64_t min_msat = 1000;
+    uint64_t max_msat = 1000000000;
+    uint64_t amount_msat = 21 * 1000;
+
+    bool ok = (amount_msat >= min_msat && amount_msat <= max_msat);
+    ok = ok && !(0 >= min_msat);
+    ok = ok && !(2000000000ULL <= max_msat);
+    return ok;
+}
+
+int main(void)
+{
+    printf("=== test_lnurl_pay ===\n");
+
+    printf("\n--- LNURL-pay response parsing ---\n");
+    ASSERT(test_parse_lnurlp_response(), "parse lnurlp response: callback + min/max");
+
+    printf("\n--- Callback response parsing ---\n");
+    ASSERT(test_parse_callback_response(), "parse callback response: extract bolt11 'pr'");
+
+    printf("\n--- Lightning address parsing ---\n");
+    ASSERT(test_lightning_address_parse(), "split 'TollGate@coinos.io' into user + domain");
+
+    printf("\n--- Amount validation ---\n");
+    ASSERT(test_amount_validation(), "21 sats (21000 msat) within [1000, 1000000000]");
+
+    printf("\n--- Missing @ in address ---\n");
+    {
+        const char *addr = "no-at-sign.com";
+        const char *at = strchr(addr, '@');
+        ASSERT(at == NULL, "no @ returns NULL");
+    }
+
+    printf("\n--- Missing callback in response ---\n");
+    {
+        cJSON *root = cJSON_Parse(SAMPLE_MISSING_CALLBACK);
+        cJSON *cb = cJSON_GetObjectItemCaseSensitive(root, "callback");
+        ASSERT(!cb, "missing callback detected");
+        cJSON_Delete(root);
+    }
+
+    printf("\n--- Missing pr in callback response ---\n");
+    {
+        cJSON *root = cJSON_Parse(SAMPLE_MISSING_PR);
+        cJSON *pr = cJSON_GetObjectItemCaseSensitive(root, "pr");
+        ASSERT(!pr, "missing pr detected");
+        cJSON_Delete(root);
+    }
+
+    TEST_SUMMARY();
+}
diff --git a/tests/unit/test_tollgate_client b/tests/unit/test_tollgate_client
new file mode 100755
index 0000000..33b272e
--- /dev/null
+++ b/tests/unit/test_tollgate_client