All workOwn product · 2026

Cíl

“Diligence gets you to the goal.”

A study app for the Cambridge B1 Preliminary, B2 First and C1 Advanced exams. Every exercise explains why the answer is the answer, it works offline without an account, and an optional AI review comments on your writing. Cíl is Czech for goal; it was split off from Píle, Czech for diligence.

cambridge-helper-cumorah.vercel.appAndroid & Windows downloadsSource on GitHub
Cíl practice screen: goal chips for B1, B2 and C1, a goal card and topic cards such as Present perfect and Passive voice
Dates
Sep 29 – 30, 2026
Platforms
Android · Windows · Web
Stack
Flutter · Vercel Functions · Groq / Anthropic
Logbook

How it was built, day by day

Written from the project's commit history. Decisions are marked in red.

  1. Launch

    Cíl ships, split off from Píle

    Exam practice pulled out of Píle into its own app. Deliberately not called anything with "Cambridge" in the name: it is an unofficial study aid and should not suggest otherwise.

  2. Decision

    The site follows main, downloads follow tags

    Every push updates the web app, while Android and Windows builds are only published from version tags. Vercel builds the Flutter web app itself with a pinned SDK, so no extra tokens are needed.

  3. Design

    Made for laptops too

    A navigation rail on desktop, constrained page widths, and writing, speaking and answer sheets reworked for wide screens.

  4. Build

    AI reviews for writing

    An optional review of a written answer through a serverless function: Groq first, Anthropic as a fallback, structured output and strict input limits. Drafts are not stored or logged, and the feedback keeps facts and valid spelling variants intact.

    The Cíl writing editor: the B2 essay task and checklist on the left, a word counter and answer box on the right
    The writing editor, with word count, timer and review button
  5. Design

    A goal of your own

    An optional nickname, reason, target date and daily target. Encouragement after answers, study reminders, and illustrations that animate once and respect reduced motion.

    A solved exercise: the correct answer highlighted, a "Well done" card with a medal and the explanation of the rule
    Every answer comes with the reason it is right
  6. Build

    Signed Android downloads

    Android releases publish on their own, without waiting for Windows, and the workflow refuses any APK that is not properly signed.

  7. Design

    Feedback for every answer in the mock tests

    After marking, each answer says whether it is correct, incorrect, partial or blank, and why. The explanations work offline.

  8. Content

    Original papers and a free listening library

    Practice papers written for Cíl with a comment for every answer, commented model essays, and British Council listening lessons linked rather than copied.

    The Mock tests screen listing papers written for Cíl, each with its time, questions and marks
    Mock tests written for Cíl, with the text included
  9. Decision

    Reviews that read what the learner wrote

    The AI review first checks whether the answer does what the task asked, then builds its suggestions on the learner’s own sentences instead of rewriting them.

  10. Content

    Three times the B1 practice

    B1 items went from 21 to 63 across three new topics, plus an original B1 Reading paper.

Cíl practice screen on a phone, with the bottom navigation bar
same site, on a phone
Back to all workStart a project