Tharser: Tiny Handheld Parser Game Engine

Tharser is a parser interactive-fiction engine for the TinyCircuits Thumby (a 72×40 pixel handheld) and the browser. Author a game once in JSON; it runs on real hardware as MicroPython and in any browser as a single self-contained HTML file.

(Thumby + Parser = Tharser.)

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⚠️ Still under development

Tharser is a work in progress. It is usable today and ships complete games, but there may be bugs, and features are still being added. If you hit a problem, a confusing corner, or something that just won't work — please reach out. Bug reports and questions are genuinely welcome and help the engine get better. Use the forum/comments below.

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What it does

• One source, two targets. Write your game as a JSON file in the editor, then export to MicroPython .py for the Thumby device or to a standalone browser .html.
• Two engine kinds. Parser (type or wheel-select commands) and Choice (branching menus). Both run on hardware and in browsers with identical behavior.
• Three input schemes. Predictive Wheel (letter wheel with autocomplete, closest to the Thumby feel), QWERTY (free typing), and Letter Wheel (cycle letters one at a time).
• Built-in reference panel. Every exported game gets an automatic, spoiler-gated FAQ — map, command list, item synonyms, hints, and an optional walkthrough — generated from your game's own data.
• Mobile-friendly out of the box. Exported games adapt to phones: a touch d-pad via swipes, tap to confirm, and a flip between the game and the menu/reference.
• The Cabinet. Bundle several games into one self-contained HTML file with a picker sidebar.

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What you get

• tharser_editor.html — the authoring tool. Open it in a browser; build, test, and export games. No install, no server, no account.
• Example games — ready-to-open samples (Cave, Closet, Cellar) showing parser and choice play.
• Example cabinet — three games in one file, to see the multi-game shell.
• STARTER_TEMPLATE.json — a documented starting point showing every game field, including the new faq, mobile, hints, and walkthrough options.
• Thumby device games — ready-to-load MicroPython .py versions of the example games. Own a Thumby? Drop them on the device and play on real hardware. (Install guide included.)
• Developer source — the full engine source for those who want to dig in.

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Games made with Tharser

Help! I am Locked in a Fortune Cookie Factory!
A complete parser text adventure that fits on a 72×40 screen — a proposed world's-smallest parser game. You're trapped in a cookie factory at demolition time; every exit fails until the one that doesn't. Submitted to ParserComp 2026.
→ outgrabe.itch.io/fortune-cookie

Connection: A Rotifer's Tale
A tiny natural-history game about a sessile rotifer that builds its own tube from rounded pellets of bacteria and detritus, held together by mucus secretion. A small, strange life rendered in small, strange pixels.
→ outgrabe.itch.io/connection-rotifer

More games are on the way. Show us what you've made with it!

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What works today — and what's coming

Tharser is in active development. It's a real, usable engine that ships finished games, but it's honest to say where the edges are right now. Here's the current state, so nothing surprises you mid-project.

Fully working

• The browser is the complete experience. Everything below works in the editor and in exported .html games: parser and choice games, all three input schemes (predictive wheel, letter wheel, QWERTY), NPCs with dialogue and gifts, the auto-reference panel, and mobile touch support.
• Parser and choice games export to the Thumby as single-file MicroPython, and run on the device.
• All three input schemes now run on hardware — including QWERTY and predictive wheel, not just the verb wheel.

Known limits on hardware (the browser has no such limits)

• NPCs — TALK and GIVE — are browser-only for now. A game that uses dialogue or gift-giving plays fully in the browser; on the Thumby those verbs aren't available yet. Rooms, items, exits, and puzzles all work on-device.
• Large games can exceed the device's memory. The Thumby is a tiny computer; very big games may run in the browser but be too heavy for the hardware. Smaller, focused games are the sweet spot on-device.
• Hardware export is newer than browser export. If a .py build misbehaves on your Thumby, that's useful information — please send the on-screen error so it can be fixed.

On the roadmap

• TALK / GIVE / NPC support on hardware, to match the browser.
• Tighter memory use so larger games fit on-device.
• More built-in verbs and richer scripting.
• More example games and templates.

None of this blocks you from making and shipping a game today — the browser path is complete, and most Thumby games will run on hardware. The notes above just mark where the frontier is. Questions and bug reports are genuinely welcome and shape what gets built next.

About

Studio: Outgrabe — indie games, interactive fiction, and scent-scored paper works. New Haven, Missouri.

The hardware: the TinyCircuits Thumby is a keychain-sized handheld with a 72×40 OLED, an RP2040 chip, and a six-button d-pad + A/B layout. It runs MicroPython. Tharser targets it directly — and the browser, for everyone without the device.

Free. No ads. No tracking.

Tharser and its games by Tyler Wright, DET — working as Outgrabe.