Crypto News (Flutter)

A small cross-platform Flutter app for reading cryptocurrency headlines. It pulls live articles from the newsdata.io news API (https://newsdata.io) — grab a free API key to run it — and shows them as a scrollable feed with per-token tags, a sentiment summary, and a simple keyword alert.

Features

• Live crypto news feed (newsdata.io /crypto endpoint), with pull-to-refresh and infinite scroll using the nextPage cursor.
• Free-text search across headlines.
• Token cards: a "trending tokens" strip built from the coins each article mentions, with a per-token headline count.
• Per-article keyword chips (always available) plus AI tag chips and an AI summary line when your plan returns them.
• Sentiment badge per article and an aggregate sentiment breakdown at the top of the feed. On a free key these fields are absent, so the chart shows a clearly labeled sample instead of leaving the space blank.
• Keyword alert: set a word (e.g. bitcoin) and get an in-app alert when a refresh brings in new matching headlines.

Requirements

• Flutter 3.10 or newer (Dart 3).
• A newsdata.io API key. The free tier covers everything above; create a key at https://newsdata.io.

Setup

1. Install dependencies:

   flutter pub get
   

2. Put your key in an environment variable:

   export NEWSDATA_API_KEY=your_key_here
   

3. Run the app, forwarding the key into the build with --dart-define:

   flutter run --dart-define=NEWSDATA_API_KEY=$NEWSDATA_API_KEY
   

The key is read at build time from the NEWSDATA_API_KEY define and is never hardcoded. If it is missing, the app shows an error explaining how to pass it.

Optional configuration

• ENABLE_PAID_MODE — when set to true, the app requests larger result pages (a size above 10). That query parameter requires a paid newsdata.io plan; on a free key the request is automatically retried without it, so you still get results.

  flutter run \
    --dart-define=NEWSDATA_API_KEY=$NEWSDATA_API_KEY \
    --dart-define=ENABLE_PAID_MODE=true
  

  Sentiment and the ai_* values are response fields, not query parameters — they arrive automatically in each article when your plan includes them, and the UI renders them when present.

Project layout

• lib/main.dart — app shell, feed screen, search, alerts, trending strip.
• lib/services/news_service.dart — newsdata.io client and error handling.
• lib/models/article.dart — article model and safe parsing of optional fields.
• lib/widgets/article_card.dart — a single article card.
• lib/widgets/sentiment_bar.dart — the sentiment breakdown widget.

Example

Searching for etf and refreshing produces a feed like:

Headline sentiment
  Positive  ########..  6
  Neutral   ####......  3
  Negative  ##........  2
  Sample — live sentiment requires a paid newsdata.io plan.

Trending tokens:  BTC · 5   ETH · 3   SOL · 2

Spot Bitcoin ETF inflows climb for a third week
CoinDesk · 2h ago
#bitcoin  #etf  #markets   [BTC]

Notes

• Network errors, an invalid key (HTTP 401), rate limiting (HTTP 429), and empty result sets are all handled with a message rather than a crash.
• newsdata.io does not provide live price quotes, so the token strip reflects how often each coin appears in the current headlines rather than market prices.

License

MIT