We use these in our new ESP8266 Sensor Server but will make more generic programming notes here.
Arduino pin numbers. source 
Developer boards available in a three-pack. CP2102 usb interface. NodeMCU firmware. amazon
We're using one-wire digital thermometers accessed via Paul Stoffregen's Arduino-compatible library hacked to meet our needs. pjrc
We can avoid hard-coding WiFi credentials into Arduino sketches using a llibrary called WiFiManager. post
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Official Espressif IoT Development Framework. github
The examples are grouped into subdirectories by category. Each category directory contains one or more example projects: - `bluetooth/bluedroid` Classic BT, BLE and coex examples using default Bluedroid host stack. - `bluetooth/nimble` BLE examples using NimBLE host stack. - `bluetooth/esp_ble_mesh` ESP BLE Mesh examples. - `bluetooth/hci` HCI transport (VHCI and HCI UART) examples. - `build_system` Examples of build system features. - `cxx` C++ language utilization examples and experimental components. - `ethernet` Ethernet network examples. - `get-started` Simple examples with minimal functionality. Good start point for beginners. - `ieee802154` IEEE802.15.4 examples. - `mesh` Wi-Fi Mesh examples. - `network` Examples related to general network environment, test & analysis. - `openthread` OpenThread examples. - `peripherals` Examples showing driver functionality for the various onboard ESP32 peripherals. - `protocols` Examples showing network protocol interactions. - `provisioning` Wi-Fi provisioning examples. - `security` Examples about security features. - `storage` Examples showing data storage methods using SPI flash, external storage like the SD/MMC interface and flash partitioning. - `system` Demonstrates some internal chip features, or debugging & development tools. - `wifi` Advanced Wi-Fi features (For network protocol examples, see `protocols` instead.) - `Zigbee` Zigbee network and device examples.