WanderWallet: A Fully Offline Travel Budget App Built in .NET MAUI Without Any Backend

·2 views

Horizon Software, a solo Android developer, has built WanderWallet, a travel budgeting app that operates entirely on-device with no backend, cloud services, or user account required. The app stores all data in a local SQLite database and handles currency conversion by caching exchange rates for around 155 currencies whenever a connection is available, freezing each rate at the time of expense entry to prevent historical budget drift. Receipt scanning uses on-device OCR via ML Kit through Plugin.Maui.OCR, with a custom text parser extracting amounts, dates, and merchant names without sending data to any external server. Trip mapping is achieved by rendering a bundled Creative Commons world image using a plate carrée projection rather than relying on a tile-streaming mapping SDK. The project demonstrates that features commonly assumed to require server infrastructure — currency conversion, OCR, and maps — can be fully implemented offline with careful architectural choices.

Read the full story at DEV Community

This is an AI-generated summary. ShortSingh links to the original source for the complete article.

Discussion (0)

Developer builds LLM pricing API, finds AI agents are its most likely users

A developer created LLM Price Watch, an API that aggregates and compares per-token pricing across major AI models including Claude, GPT, Gemini, DeepSeek, and Grok. Beyond standard pricing endpoints, a recommendation endpoint was added that suggests the best model for a given use case — such as coding assistance or document summarization — based on both cost and editorial analysis. The developer noted that AI agents performing runtime tool selection, not just human developers, emerged as a core audience for the API. Design decisions like open CORS and no API key requirement were made deliberately to reduce friction for agent-based callers. Pricing data was verified directly against each provider's official pages to avoid the lag common in third-party aggregators.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

Open-source audit reveals how 18 major sites secretly filter AI crawlers

A developer built an open-source tool called geo-crawl-audit to test how major websites treat AI web crawlers such as GPTBot, ClaudeBot, and PerplexityBot compared to regular browsers. Testing 18 prominent sites on August 7, the audit found that firewall configurations often contradict stated robots.txt policies, effectively making crawler access a business decision rather than a technical one. The New York Times, currently in litigation with OpenAI, blocked nearly all AI crawlers, while The Guardian, which holds a content deal with OpenAI, selectively allowed OpenAI bots but blocked Anthropic and Perplexity crawlers. Reddit's robots.txt disallows all AI bots, yet several were served live content anyway, exposing the gap between declared policy and actual enforcement. The audit also highlighted that most major AI crawlers do not execute JavaScript, meaning heavily client-rendered sites like LinkedIn and Reddit expose near-empty pages to crawlers regardless of access permissions.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

Docker Basics Explained: Images, Containers, Ports, and Volumes Demystified

Docker is a platform that packages applications along with their dependencies into isolated environments called containers, solving the common 'it works on my machine' problem. A Docker image is a read-only blueprint containing the application code, runtime, and configuration, while a container is a live, running instance created from that image. A single image can be used to spin up multiple containers simultaneously, making applications highly portable and scalable. Port mapping bridges the gap between a container's internal network and the host machine, allowing external access using the syntax -p HOST_PORT:CONTAINER_PORT. Understanding these four core concepts — images, containers, ports, and volumes — forms the foundation needed to work effectively with Docker.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

Digital Marketer Builds Browser Games Using Only HTML, CSS, and JavaScript

A digital marketer behind GamesMom, a free browser-based educational games platform for children, shared lessons learned from building interactive games without a dedicated game engine. The project, which includes math, word, typing, and memory games playable without downloads or accounts, revealed that many simple games can be built using just HTML, CSS, and vanilla JavaScript. The author found that starting with the question of what a specific game actually needs — rather than reaching for complex frameworks — led to simpler, more manageable solutions. Key concepts like browser event listeners and JavaScript timers proved sufficient for most of the interactivity required. The experience highlighted that a sophisticated technology stack is not always necessary to deliver functional, engaging web-based experiences.

0 comments Read more at DEV Community