78Worlds

A tarot reading has several steps: choosing a spread, drawing or recording the cards, interpreting them and keeping the result to consult later. 78Worlds brings those steps together in one mobile app.

78Worlds is a mobile tarot app, built with React Native and Expo, that offers 22 ready-made spreads, three decks of 78 cards and an interface in six languages.

The person asks a question, chooses a spread and a deck, and the app guides the reading to the end. Its features include:

• automatic readings, in which the app draws the cards and the person reveals them by tapping a fan, or manual readings, in which the person records the cards drawn from a physical deck;
• 22 ready-made spreads, grouped by the intent of the question (everyday, conflicts, processes, relationships and self-knowledge), with favorites and a card-of-the-day option;
• a visual editor for custom spreads, with automatic AI translation into the six languages that can be reviewed before saving;
• three decks of 78 cards: Rider-Waite, Tarot de Marseille and the app’s own 78Worlds deck;
• AI interpretation with a light and shadow analysis and practical advice, plus spread suggestions based on the question;
• a history with search and filters, notes per card and an overall note, a photo attached to manual readings, export to JSON and PDF, and sharing as an image;
• a card encyclopedia, reading statistics, a Learn tab with five sections of educational content, and a light, dark or system theme.

The flow has four phases: question, spread and mode, cards, and reading. On the spread preview, the person sees the diagram, the description and the meaning of each position, and chooses between automatic and manual mode.

Readings, spreads, decks and the language and theme preferences are stored on the device. The Supabase edge function is involved only in the AI features (interpretation, spread suggestions and statistics insights) and in translations. The app works without a connection using what is stored on the device; the AI features need the network.

To keep the interpretation from inventing details of the card art, the request includes a visual description of each card in the deck being used. The instruction forbids claims about images without a supplied description.

78Worlds is in beta. It is distributed for testing, with TestFlight builds on iOS. The app’s code is proprietary.

Sigil Labs built 78Worlds, and it applies two of the studio’s services: custom software, in the mobile app, and AI and LLM work, in the interpretation layer. Some of the practices behind how that layer is run:

• the default reading model was chosen by a blind, paired test of 30 generated readings (2 models, 3 scenarios, 5 repetitions);
• the test ended in a tie on the objective measures; the chosen model cost 40% of the previous one and wrote about 25% less, and the decision came from human preference over shuffled, unlabeled pairs;
• the project rule is to pin the exact model identifier, never an alias that the vendor can point at a different model with no change on our side;
• an automated check confirms the server’s health every two hours and makes one real AI call per day, with messages that name the cause of a failure;
• metrics and error telemetry is on by default and can be switched off in Settings. Metric events carry only identifiers, enumerations and numbers; the typed event catalog rejects the question, the context and the notes at compile time.