--- title: "Simple statutory interest on a principal at the cited statutory-interest series rate (Actual/365)" method: POST path: "/v1/answers/statutory-interest" tags: ["Answers"] --- # Simple statutory interest on a principal at the cited statutory-interest series rate (Actual/365) `POST /v1/answers/statutory-interest` ## Request - Base URL: `https://mearef.dev` - URL: `https://mearef.dev/v1/answers/statutory-interest` - Auth: one of: - API key in header `PAYMENT-SIGNATURE` - API key in header `X-PAYMENT` - API key in header `X-API-Key` Simple interest at the cited statutory rate (Actual/365, `from` inclusive, `to` exclusive), 2 dp with workings. Not legal advice; no compounding. Give `days` or `from`+`to`; bad input is refused free. receipt:true embeds an answer_receipt. ## Headers - `X-Free-Trial` '1' ## Request body - object - `country` 'ae' | 'bh' | 'il' | 'iq' | 'jo' | 'kw' | 'om' | 'qa' | 'sa', required: ISO 3166-1 alpha-2 in this brand's catalog that holds a statutory-interest series. - `principal` number, required: Principal in the country's currency. Must be a finite number greater than 0. - `days` number: Positive day-count days. Supply this, or from and to. If both are sent and disagree, the call is 400 free. - `from` string, date: Start date YYYY-MM-DD, inclusive. Required together with to when days is omitted. - `to` string, date: End date YYYY-MM-DD, exclusive. Day count is the UTC calendar difference to − from. - `receipt` boolean: Optional. Default false. When true, a paid HTTP 200 embeds an Ed25519-signed receipt (kind answer_receipt) the caller can file and later verify at /certified/public-key. Included in this answer's existing price — no extra charge. The field is omitted on unpaid 402 and on free 4xx refusals. This is not a series certified extract: GET /v1/certified/{country}/{series} is a different artifact, with its own price. ## Response `200` Interest, the cited rate, Actual/365 workings, disclaimer and limitations. Optional property receipt (schema AnswerReceipt, kind answer_receipt) is present only when the request set receipt:true and this response is a paid HTTP 200. Unpaid 402 and free 4xx refusals do not include receipt. Not a series certified extract (GET /v1/certified/{country}/{series}). - object: Simple statutory interest on the cited statutory-interest series. The rate is that series' numeric value after derived materialization, not a rate invented for this call. Interest is rounded to 2 decimal places. Not legal advice. - `status` 'ok', required - `confidence_label` 'high' | 'medium' | 'low': Derived from source type, verification age, stale. Rules: /label-rules - `coverage_label` 'ready' | 'partial' | 'gap': ready=complete, partial=limited, gap=no number. Rules: /label-rules - `label_basis` object: Inputs and rule ids behind both labels - `country` string, required: ISO 3166-1 alpha-2 - `principal` number, required - `days` number, required: Day-count days used. From the request, or the UTC calendar difference to − from. - `rate` number, required: Cited series rate in percent, after the same materialization as GET /v1/{country}/statutory-interest. - `rate_unit` 'percent', required - `day_count_basis` 'actual/365_simple', required - `interest` number, required: principal × (rate / 100) × (days / 365), rounded to 2 decimal places. - `workings` string, required: The arithmetic, including the 2-decimal rounding. - `disclaimer` string, required: COMPUTED_DISCLAIMER. This is a computation, not a cited value and not advice. - `limitations` string[], required: Always populated. Not legal advice; the computation is over the cited series as of last_confirmed; Actual/365 simple only. - `provenance` object, required - `effective_from` string, date, nullable - `last_confirmed` string, date, nullable - `source` object - `name` string - `url` string - `receipt` AnswerReceipt: Signed record of one paid answer computation. Present only on HTTP 200 when the request body set receipt:true. kind is answer_receipt. This object is not a series certified extract: GET /v1/certified/{country}/{series} returns a different artifact (value, citation, archived-source fingerprint, verification chain) at its own price. An answer receipt is included in the answer's existing price — no extra charge. It is not legal advice. It only covers the computation over the cited series as of each series' last_confirmed. Signing: build the object without signature, set receipt_id from the sha256 of that canonical JSON (first 24 hex chars, same pattern as extract_id), re-canonicalize including receipt_id, then sign. Verify with the free key at /certified/public-key — the same key and the same canonicalization rule as series certified extracts, not a second key. - `kind` 'answer_receipt', required - `receipt_id` string, required: First 24 hex characters of sha256 over the canonical JSON of this object before signature is attached. Same pattern as certified extract_id. The signature covers the object including receipt_id. - `answer` string, required: Route or tool name of the paid answer, e.g. vat, wage-check, working-days, settlement-date, income-tax, statutory-interest, payroll, employment-cost. - `request` object, required: Sanitized inputs echoed from the request. Properties are route-specific. - `result` object, required: Compact summary of the answer status and workings already returned on this 200. Properties are route-specific. - `cited_series` object[], required: Series the computation cited. Empty only when the answer cited none. - `country` string, required - `series_id` string, required - `value` union, required: Cited series value as held. Number, string, or null. - number - string - `last_confirmed` string, date, nullable, required: ISO date the cited series was last confirmed, or null. - `source_url` string, nullable, required - `source_sha256` string, nullable, required: Hex fingerprint from provenance when available, otherwise null. - `issued_at` string, date-time, required: ISO8601 timestamp when the receipt was issued. - `limitations` string[], required: Always populated. States that this receipt is not a series certified extract and is not legal advice, and that it only covers the computation over the cited series as of each series' last_confirmed. - `signature` object, required: Ed25519 signature over the canonical JSON of this receipt with the signature field omitted. Same key_id and same canonicalization rule as series certified extracts, published at /certified/public-key. Not a second production key. - `alg` 'Ed25519', required - `key_id` string, required: Same key_id as GET /certified/public-key and as series certified extracts. - `public_key` string, required: Absolute URL of GET /certified/public-key. - `signed_payload` string, required: canonical JSON of answer_receipt: keys sorted recursively, no whitespace (see /certified/public-key) - `value` string, required: Base64 Ed25519 signature. ## Other responses - `400`: Invalid body, free, before payment. No receipt. Includes a non-finite or non-positive principal, a bad date, days together with from/to that disagree, or receipt that is not a boolean. - `402`: Payment Required. No receipt object is returned on 402, including when the body set receipt:true. - `404`: Unknown country for this brand, or no statutory-interest series for that country. Free. No receipt. - `422`: Free, before payment. No receipt. The statutory-interest series is present but has no numeric rate after derived materialization (current value null or not a number). Typical of a mechanism-only series, for example a treasury-bill reference that does not publish a prescribed percent. The body includes the series notes or explanation. A non-answer is never sold. --- [API](https://skmtc.dev/mearef/apis/mearef-middle-eastern-government-reference-data.md) · [All operations](https://skmtc.dev/mearef/apis/mearef-middle-eastern-government-reference-data/llms.txt) · [OpenAPI document](https://skmtc.dev/mearef/apis/mearef-middle-eastern-government-reference-data/revisions/7b64e3502210?raw)