How to install MicroWebSrv on an ESP32?

Copy the three core files (microWebSrv.py, microWebSocket.py, microWebTemplate.py) to your device's flash, typically in /flash/www, then import and start the server with mws.Start(threaded=True) as shown in the basic example. Ensure MicroPython is properly set up on the ESP32 first.

MicroWebSrv vs MicroWebSrv2: which is better?

MicroWebSrv2 is the newer version with enhanced features and likely better maintenance. For new projects, consider MicroWebSrv2, but MicroWebSrv remains useful for simpler, compatible setups on older MicroPython environments.

Does MicroWebSrv support JSON APIs?

Yes, it handles JSON payloads via methods like httpClient.ReadRequestContentAsJSON() and httpResponse.WriteResponseJSONOk(), making it suitable for building REST APIs directly on microcontrollers, as demonstrated in the route handlers.

How to create a captive portal with MicroWebSrv?

Use mws.SetNotFoundPageUrl() to redirect unmatched requests to your device's IP or domain, and integrate with a DNS server like MicroDNSSrv to intercept all queries for seamless Wi-Fi configuration portals.

What are the limitations of .pyhtml templating?

.pyhtml files allow embedded MicroPython code but have a simple syntax with limited control structures (like if, for loops). They rely on the microWebTemplate.py module and may not support advanced templating features found in full web frameworks.

Can MicroWebSrv handle file uploads?

The README shows support for reading posted form data via httpClient.ReadRequestPostedFormData(), which can handle file uploads in multipart forms, but it's basic and may require manual processing due to microcontroller memory limits.

Open-Awesome

MicroWebSrv

MITPython

A lightweight HTTP web server with WebSocket support and Python templating for MicroPython on ESP32 and Pycom devices.

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What is MicroWebSrv?

MicroWebSrv is a micro HTTP web server built for MicroPython, enabling embedded devices like ESP32 and Pycom modules to host web interfaces and APIs. It provides essential web server functionalities—including routing, WebSocket support, and Python-based HTML templating—in a lightweight package suitable for resource-limited environments. The project solves the need for a simple, integrated web server on microcontrollers without requiring complex infrastructure.

Target Audience

Embedded developers and IoT engineers working with MicroPython on devices such as ESP32, Pycom modules, or Pyboard D-series who need to add web-based configuration, monitoring, or interaction capabilities.

Value Proposition

Developers choose MicroWebSrv for its minimal footprint, ease of integration, and comprehensive feature set tailored for MicroPython. Unlike generic web servers, it is optimized for embedded systems, offering WebSockets, templating, and REST support out of the box with just three files, reducing overhead and complexity.

Overview

A micro HTTP Web server that supports WebSockets, html/python language templating and routing handlers, for MicroPython (used on Pycom modules & ESP32)

Use Cases

Best For

Adding a web configuration interface to ESP32-based IoT devices
Creating captive portals for Wi-Fi setup on microcontroller projects
Building REST APIs directly on MicroPython-enabled hardware
Serving dynamic web pages with embedded Python logic via .pyhtml templates
Implementing real-time data dashboards using WebSockets on embedded systems
Developing lightweight web servers for Pycom or Pyboard D-series modules

Not Ideal For

Projects requiring high-concurrency web serving, as embedded devices have limited RAM and CPU for handling multiple simultaneous connections.
Development on standard Python (CPython) environments, since MicroWebSrv is specifically optimized for MicroPython on microcontrollers.
Applications needing built-in HTTPS encryption, as the server lacks native support for secure communications.
Teams seeking extensive plugin ecosystems or middleware, due to its minimalistic, three-file design with no extension framework.

Pros & Cons

Pros

Minimal Footprint

Consists of only three files (microWebSrv.py, microWebSocket.py, microWebTemplate.py), making it easy to integrate and lightweight for resource-constrained MicroPython devices like ESP32.

WebSocket Support

Enables real-time, bidirectional communication through optional WebSockets, allowing for fast data exchange in IoT dashboards or interactive interfaces.

Python Templating

Uses .pyhtml files to embed MicroPython code directly in HTML, enabling dynamic page rendering without external templating engines, as detailed in the examples.

Captive Portal Ready

Easily redirects all not-found queries via SetNotFoundPageUrl(), simplifying Wi-Fi setup portals for device configuration, often paired with MicroDNSSrv.

Cons

Outdated and Superseded

The README actively promotes MicroWebSrv2, indicating this version is legacy and may lack recent updates, bug fixes, or new features.

No HTTPS Support

Lacks built-in encryption for secure connections, requiring additional layers or proxies for applications handling sensitive data.

Limited Performance Scalability

Designed for low-traffic scenarios on microcontrollers; performance can degrade with multiple concurrent connections or heavy WebSocket usage due to hardware constraints.

Frequently Asked Questions

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