Faraid Visualizer

The problem

Dividing an inheritance under Islamic law (faraid) is a common source of family disputes in Indonesia. Few people outside pesantren-trained scholars can do the calculation. Online calculators oversimplify, quietly pick one school of law, or print a number with no working. People accept a result more readily when they can follow the reasoning.

There is a second problem underneath. Indonesia's Compilation of Islamic Law (KHI, Inpres No. 1/1991) and classical Syafi'i fiqh differ on points that change the answer. These include substitute heirs (KHI Pasal 185), where the remainder goes when no eligible heir is left, and deducting marital joint property before the estate is divided. Most calculators blur the two.

What I built

Every share points to its source

I wrote the calculation engine as a standalone Python package with no outside dependencies. Each result records the heir, the share, the rule applied and the source for that rule. I built the citation list before any logic: 35 sources, including 14 KHI articles, classical references, Qur'anic verses and hadith. Qur'an and hadith are stored as references, never reproduced text. A rule with no source fails the tests and can't ship.

KHI and Syafi'i are two separate rule sets

I modelled each school as its own rule set, with its own choices and citations. The same family can run under both, side by side, so a user sees exactly where the answers part. A predeceased child's children, for example, inherit under KHI and not under classical Syafi'i. Hanafi, Maliki and Hanbali rule sets also exist, marked Beta.

When a case isn't covered, it says so

Some family configurations have intricate sub-cases, such as certain grandfather-and-siblings cases, that the engine doesn't cover. There it stops and says "this configuration isn't supported yet". It never falls back to a nearest match. The page shows this as a normal answer, and the site states that its results are educational, not a legal ruling. Rounding is shown too. Shares can sum a cent off the estate, and moving that cent would be a fiqh decision, so the page shows the gap.

The same Python engine runs in the browser

The first version was a Django site with a database. Inheritance data is about as private as data gets, so I moved to a static site that never receives it. The browser downloads a Python runtime and runs the same package the server runs. Nothing leaves the device. A case can be shared because it is encoded in the link. A cold first load takes about 20 seconds, so the form works straight away while the engine loads in the background. A later pass added a guided, family-tree picker for Personal mode, drawing relationships around the deceased instead of filling a form, but sending the engine the exact same data either way.

Tests decide whether it ships

The deploy runs the validation bank and the API tests. It also checks that no AI model call exists in the calculation code, and that the built site contains the engine. Any failure blocks the release. Every new rule arrived with its source and a test in the same change.

Result

Faraid Visualizer is live and free on GitHub Pages, with no backend and no account. It shows who is blocked and by whom, each fixed share, how the remainder splits, and every citation, as text and as a diagram. KHI and classical Syafi'i pass all 61 worked examples in the validation bank, plus a separate set of cases where the two schools disagree. Professional mode exports a PDF with the full citation trail, in Indonesian or English, for notaries and court staff. I built it alone in two phases: the engine, the static-site move and PDF export in July and early August 2026. A later pass through September added the guided family-tree input and redesigned the derivation view.