Provisioning - first-boot WiFi setup via a captive portal

Layer: L7 Application · Build flags: PC_ENABLE_PROVISIONING

What this example teaches

On first boot, with no stored credentials, the device brings up a softAP ("PC-Setup") and a catch-all DNS responder (raw lwIP UDP, no add-on library), so joining the AP with a phone pops a credentials form. The submitted SSID/PSK persist to NVS; on the next boot the device finds them, connects as a station, and serves normally. No external libraries are needed: just WiFi softAP, lwIP UDP, and Preferences (NVS).

The boot decision: load credentials, else open the portal.

char ssid[33], psk[64];
if (pc_provisioning_load(ssid, sizeof(ssid), psk, sizeof(psk))) {
    init_wifi_physical(ssid, psk);          // we have creds -> normal station
    server.on("/", HttpMethod::HTTP_GET, handle_root);
    server.begin(80);
} else {
    server.begin(80);
    pc_provisioning_begin(server, "PC-Setup"); // no creds -> captive portal
}

pc_provisioning_load() returns false until the device has been provisioned; pc_provisioning_begin() stands up the softAP, the catch-all DNS, and the form handler that writes NVS and reboots. To re-provision later, call pc_provisioning_clear() (for example from a button handler).

Build and run

pio ci --board=esp32dev --project-option="framework=arduino" \
  --project-option="build_flags=-DPC_ENABLE_PROVISIONING=1" \
  --lib="." examples/L7-Application/Provisioning/Provisioning.ino

Flash, join the WiFi network "PC-Setup" with a phone, open any page to reach the captive portal, and submit your network's SSID/password. The device reboots into station mode.

Annotated source

The complete sketch (Provisioning.ino), reproduced verbatim with added explanatory comments:

// Copyright (C) 2026 Douglas Quigg (dstroy0) <dquigg123@gmail.com>
// SPDX-License-Identifier: AGPL-3.0-or-later
 
#define PC_ENABLE_PROVISIONING 1
 
#include "protocore.h"
#include "network_drivers/physical/physical.h"
#include "services/provisioning_service.h"
 
PC server;
 
void handle_root(uint8_t slot_id, HttpReq *req)
{
    (void)req;
    server.send(slot_id, 200, "text/plain", "Provisioned - hello from station mode!");
}
 
void setup()
{
    Serial.begin(115200);
 
    char ssid[33];
    char psk[64];
    if (pc_provisioning_load(ssid, sizeof(ssid), psk, sizeof(psk)))
    {
        // Credentials present: connect as a normal station.
        init_wifi_physical(ssid, psk);
        Serial.print("Connecting to ");
        Serial.println(ssid);
        while (!wifi_ready())
            delay(250);
        uint32_t ip = pc_net_egress_ip(); // library egress IP (network byte order), no Arduino WiFi
        Serial.printf("IP: %u.%u.%u.%u\n", (unsigned)(ip & 0xFF), (unsigned)((ip >> 8) & 0xFF),
                      (unsigned)((ip >> 16) & 0xFF), (unsigned)((ip >> 24) & 0xFF));
 
        server.on("/", HttpMethod::HTTP_GET, handle_root);
        server.begin(80);
        Serial.println("Station mode; serving on port 80");
    }
    else
    {
        // No credentials: bring up the captive portal (softAP + catch-all DNS + form).
        server.begin(80);
        pc_provisioning_begin(server, "PC-Setup");
        Serial.println("Provisioning: join WiFi 'PC-Setup' and open any page");
    }
}
 
void loop()
{
    server.handle();
}