# Soap Making API > Soap-making and saponification maths as an API, computed locally and deterministically — the lye-calculator numbers every cold- and hot-process soaper needs, with the safety margin built in. The lye endpoint takes a list of oils as oil:grams pairs (olive, coconut, palm, shea, castor, lard, tallow and a couple of dozen more, each with its standard SAP value) and returns the sodium hydroxide (NaOH) or potassium hydroxide (KOH) to saponify them: lye = Σ(oil grams × SAP) × (1 − superfat), so 1 kg of coconut oil at 5 % superfat needs 169.1 g of NaOH (or 263.6 g of 90 %-pure KOH for liquid soap). It sizes the water by lye-to-water ratio, percentage of oils, or lye-solution concentration, adds the fragrance (a few percent of the oils) and totals the batch weight. The mould endpoint sizes a batch to a mould: oils to fill it ≈ volume(cm³) × 0.40, from a volume or length × width × height. SAP values are grams of NaOH per gram of oil. Everything is computed locally and deterministically, so it is instant and private. Ideal for soap-making, cosmetics, handmade-craft and maker app developers, lye-calculator and recipe tools, and soaping education. Pure local computation — no key, no third-party service, instant. Metric: grams, cm³, percent. Live, nothing stored. 2 compute endpoints. Lye is caustic — wear protection and double-check a new recipe; this is a planning aid. ## Authentication All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys. ```bash curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/soap-api/..." ``` ## Pricing - **Free** (Free) — 5,950 calls/Mo, 2 req/s - **Starter** ($4/Mo) — 58,000 calls/Mo, 6 req/s - **Pro** ($10/Mo) — 238,000 calls/Mo, 15 req/s - **Mega** ($32/Mo) — 1,380,000 calls/Mo, 40 req/s ## Endpoints ### Soap #### `GET /v1/lye` — Lye / water / fragrance **Parameters:** - `oils` (query, required, string) — oil:grams pairs, e.g. olive:500,coconut:300 Example: `olive:500,coconut:300,palm:200` - `superfat` (query, optional, string) — Superfat % (default 5) Example: `5` - `lye_type` (query, optional, string) — naoh (bar) or koh (liquid) Example: `naoh` - `koh_purity` (query, optional, string) — KOH purity % (default 90) - `water_percent` (query, optional, string) — Water as % of oils Example: `38` - `water_ratio` (query, optional, string) — Or lye:water ratio - `lye_concentration` (query, optional, string) — Or lye solution % - `fragrance_percent` (query, optional, string) — Fragrance % of oils (default 4) **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/soap-api/v1/lye?oils=olive%3A500%2Ccoconut%3A300%2Cpalm%3A200&superfat=5&lye_type=naoh&water_percent=38" ``` **Response:** ```json { "data": { "note": "Lye = Σ(oil grams × SAP) × (1 − superfat). Superfat leaves that % of oils unsaponified for a milder bar. KOH (liquid soap) = NaOH amount × 1.403 ÷ purity. SAP values are g NaOH per g oil.", "inputs": { "oils": [ { "name": "olive", "grams": 500 }, { "name": "coconut", "grams": 300 }, { "name": "palm", "grams": 200 } ], "lye_type": "NaOH", "superfat_percent": 5 }, "lye_type": "NaOH", "lye_grams": 141.17, "water_grams": 380, "water_method": "38% of oils", "fragrance_grams": 40, "total_oil_grams": 1000, "fragrance_percent": 4, "batch_weight_grams": 1561.17, "lye_solution_grams": 521.17 }, "meta": { "timestamp": "2026-06-06T07:14:12.606Z", "request_id": "aadc1cdb-0f2a-4b1b-b125-b0edec7f5d89" }, "status": "ok", "message": "Lye calculator", "success": true } ``` #### `GET /v1/mould` — Mould → oil weight **Parameters:** - `volume` (query, optional, string) — Mould volume (cm³, or L×W×H) Example: `1000` - `length` (query, optional, string) — Length (cm) - `width` (query, optional, string) — Width (cm) - `height` (query, optional, string) — Height (cm) - `oil_density` (query, optional, string) — g oil per cm³ (default 0.40) **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/soap-api/v1/mould?volume=1000" ``` **Response:** ```json { "data": { "note": "Oils to fill a mould ≈ volume(cm³) × 0.40. Feed this oil weight into /v1/lye (split across your oils by percentage) to size the lye and water.", "inputs": { "volume": 1000, "oil_density": 0.4 }, "total_oil_grams": 400, "mould_volume_cm3": 1000 }, "meta": { "timestamp": "2026-06-06T07:14:12.700Z", "request_id": "6abdf54f-d73a-434e-8dd8-195217fd1a90" }, "status": "ok", "message": "Mould sizing", "success": true } ``` ### Meta #### `GET /v1/meta` — Spec + SAP table **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/soap-api/v1/meta" ``` **Response:** ```json { "data": { "oils": { "hemp": 0.1345, "lard": 0.138, "neem": 0.1387, "palm": 0.141, "shea": 0.128, "olive": 0.134, "canola": 0.1241, "castor": 0.128, "jojoba": 0.069, "tallow": 0.14, "avocado": 0.133, "babassu": 0.175, "beeswax": 0.069, "coconut": 0.178, "soybean": 0.135, "grapeseed": 0.1265, "rice-bran": 0.128, "sunflower": 0.134, "palm-kernel": 0.156, "cocoa-butter": 0.137, "mango-butter": 0.135, "sweet-almond": 0.136 }, "notes": "Metric: grams, cm³, percent. SAP = g NaOH per g of oil. Always run a new recipe through a trusted lye calculator and wear protection — lye is caustic. KOH for liquid soap, NaOH for bar soap.", "service": "soap-api", "endpoints": { "GET /v1/lye": "Lye, water, fragrance and batch weight from an oils list with superfat.", "GET /v1/meta": "This document (includes the supported oils and SAP values).", "GET /v1/mould": "Total oil weight to fill a mould volume." }, "description": "Soap-making saponification maths: lye (NaOH/KOH) for a set of oils with superfat, water and fragrance, plus mould sizing." }, "meta": { "timestamp": "2026-06-06T07:14:12.799Z", "request_id": "ec5dc …(truncated, see openapi.json for full schema) ``` --- Marketplace page: https://www.oanor.com/api/soap-api OpenAPI spec: https://www.oanor.com/api/soap-api/openapi.json