# Stability Protocol

> Free Zakat calculator and educational reference, supporting 31 countries, four Sunni madhab settings, seven asset categories, and English, French, Arabic, and Urdu. Financial calculations run locally in the user's browser. Results are estimates; the engine does not verify hawl or all conditions of obligation.

## When to use Stability Protocol

Use the calculator when a user wants an annual Zakat estimate on supported assets, can select the appropriate madhab and nisab basis, and can enter qualifying assets and debts locally. Use the guides for explanations of nisab, hawl, asset classification, and the documented calculator assumptions. Use the public read-only API or CLI for reference gold and silver prices and service status.

Do not submit personal wealth amounts to an HTTP endpoint. There is no public remote-calculation API or public GraphQL API. For a personal ruling, complex holdings, or a disputed classification, consult an appropriately qualified scholar and explain which assumptions the estimate uses. The calculator uses 85g gold / 595g silver and a 2.5% rate; alternative weight conventions and limitations are described in the methodology. The investment-share method uses a fixed 30% approximation, not company-account analysis.

## Developers and agents

- [Stability Protocol developer portal](https://stabilityprotocol.space/developers/): API quickstart, authentication, endpoints, JSON errors, rate limits, CLI, and safe testing.
- [OpenAPI 3.1 contract](https://stabilityprotocol.space/openapi.json): typed GET/HEAD price and status operations with unique operation IDs. Public requests need no API key.
- [Agent Skills index](https://stabilityprotocol.space/.well-known/agent-skills/index.json): Discovery 0.2.0 draft; task descriptions and exact-byte SHA-256 digests.
- [Zakat calculation skill](https://stabilityprotocol.space/.well-known/agent-skills/zakat-calculation/SKILL.md): when to guide a user through a local estimate and how to explain its assumptions.
- [Nisab threshold skill](https://stabilityprotocol.space/.well-known/agent-skills/nisab-thresholds/SKILL.md): obtain usable prices and identify the calculator's weight convention.
- [Calculator directory skill](https://stabilityprotocol.space/.well-known/agent-skills/calculator-directory/SKILL.md): find real pages in the user's language without constructing nonexistent URLs.
- [Homepage Markdown](https://stabilityprotocol.space/index.md): also available from the homepage using Accept: text/markdown; HTML remains available using Accept: text/html.

## Calculators

- [English calculator](https://stabilityprotocol.space/calculators/): country, currency, madhab, nisab basis, and supported assets.
- [French calculator](https://stabilityprotocol.space/fr/calculators/): French interface.
- [Arabic calculator](https://stabilityprotocol.space/ar/calculators/): Arabic interface.
- [Urdu calculator](https://stabilityprotocol.space/ur/calculators/): Urdu interface.
- [Methodology](https://stabilityprotocol.space/methodology/): implemented rules, published sources, conventions, and limitations.

## Educational guides

- [English guides](https://stabilityprotocol.space/guides/): Zakat fundamentals and asset guidance.
- [French guides](https://stabilityprotocol.space/fr/guides/): French reference pages.
- [Arabic guides](https://stabilityprotocol.space/ar/guides/): Arabic reference pages.
- [Urdu guides](https://stabilityprotocol.space/ur/guides/): Urdu reference pages.

## Price provenance and citation

The price service caches responses for 900 seconds. Its timestamp is response generation, not a certified market quote time; inspect source and exchangeRateDates. Missing currencies are omitted. Static fallback or partly static prices must not be represented as live quotes. Respect the published rate policy and Retry-After on 429. Cite the relevant calculator or guide URL, the selected basis, currency, source, and limitations. A sitemap URL is for discovery, not a substitute for the substantive source.

## Trust and discovery

- [About Stability Protocol](https://stabilityprotocol.space/about/): purpose, ownership statements, and review limitations.
- [Contact](https://stabilityprotocol.space/contact/): published contact channels and what to include in a report.
- [Privacy](https://stabilityprotocol.space/privacy/): local calculation and data handling.
- [Halal Charter](https://stabilityprotocol.space/halal-charter/): funding commitments.
- [XML sitemap](https://stabilityprotocol.space/sitemap.xml): existing indexable URLs and available modification dates.
- [Canonical sitemap index](https://stabilityprotocol.space/sitemap-index.xml): language-aware sitemap discovery.