API Reference

Base URL: https://apibase.dev/v1

API Key required. Pass your key via X-Api-Key header on every request. Get a key →

Authentication

Include your API key in the X-Api-Key request header. Alternatively, pass it as a query parameter ?api_key=.

# Recommended: header
curl https://apibase.dev/v1/spellnumber?number=1000 \
     -H "X-Api-Key: sk_live_your_key_here"

# Alternative: query param
curl "https://apibase.dev/v1/spellnumber?number=1000&api_key=sk_live_your_key_here"

Errors

HTTP Status	Meaning
`200`	Success
`401`	Missing API key
`403`	Invalid key or quota exceeded
`400`	Bad parameter value (unsupported language, country, or year)
`422`	Missing or invalid required parameter (e.g., non-numeric `number`, NIK not 16 digits)

Quota

Every response includes a quota object showing your current usage. Each successful request counts as 1 call. Quota resets monthly with your billing cycle.

"quota": {
  "used":       3,
  "limit":      10000,
  "remaining":  9997,
  "resets_at":  "2026-07-23 10:00:00"
}

Quota resets automatically each billing cycle (triggered by renewal payment).

Spell Number

Convert any integer into its written-word equivalent in 19 languages.

GET /v1/spellnumber

Parameters

Parameter	Type	Required	Description
`number`	integer	required	The number to spell out. Supports negative numbers. Range: up to ±999 trillion.
`lang`	string	optional	Language code. Default: `id`. 19 supported — see full list ↓

Example requests

# Indonesian (default)
curl "https://apibase.dev/v1/spellnumber?number=1500000&lang=id" \
     -H "X-Api-Key: sk_live_your_key"

# English
curl "https://apibase.dev/v1/spellnumber?number=1500000&lang=en" \
     -H "X-Api-Key: sk_live_your_key"

# Chinese
curl "https://apibase.dev/v1/spellnumber?number=1500000&lang=zh" \
     -H "X-Api-Key: sk_live_your_key"

# Negative number
curl "https://apibase.dev/v1/spellnumber?number=-42&lang=en" \
     -H "X-Api-Key: sk_live_your_key"

Example responses

// lang=id
{
  "number": 1500000,
  "words":  "satu juta lima ratus ribu",
  "lang":   "id",
  "quota":  { "used": 1, "limit": 10000, "remaining": 9999 }
}

// lang=en
{
  "number": 1500000,
  "words":  "one million five hundred thousand",
  "lang":   "en",
  "quota":  { "used": 2, "limit": 10000, "remaining": 9998 }
}

// lang=zh
{
  "number": 1500000,
  "words":  "一百五十万",
  "lang":   "zh",
  "quota":  { "used": 3, "limit": 10000, "remaining": 9997 }
}

NIK Decoder

Decode an Indonesian NIK (Nomor Induk Kependudukan — 16-digit national ID number). Extracts province, birth date, gender, and district code.

GET /v1/nik

Parameters

Parameter	Type	Required	Description
`nik`	string	required	16-digit Indonesian NIK number.

NIK structure

Digits	Meaning
`1–2`	Province code
`3–4`	City / regency (kabupaten/kota) code
`5–6`	District (kecamatan) code
`7–12`	Date of birth (DDMMYY). For women, DD is DD+40 (e.g., born on the 5th → `45`).
`13–16`	Unique sequence number

Example request

curl "https://apibase.dev/v1/nik?nik=3201010150020001" \
     -H "X-Api-Key: sk_live_your_key"

Example response

{
  "nik":             "3201010150020001",
  "valid":           true,
  "province":        { "code": "32", "name": "Jawa Barat" },
  "city_code":       "3201",
  "district_code":   "320101",
  "birth_date":      "2002-02-01",
  "gender":          "M",
  "sequence":        1,
  "quota":           { "used": 1, "limit": 10000, "remaining": 9999 }
}

// Female example (DD+40): NIK with digits 7-8 = "45" → born on the 5th, gender F
{
  "gender":     "F",
  "birth_date": "2002-02-05"
  // ... other fields
}

Bank Holiday

Indonesian public holiday and joint-leave (cuti bersama) calendar. Data sourced from official Keputusan Bersama (Joint Ministerial Decree) published annually by the Indonesian government. Currently covers 2025–2026.

GET /v1/holidays

Parameters

Parameter	Type	Required	Description
`country`	string	optional	Country code. Default: `ID`. Available: `ID` Indonesia · `SG` Singapore · `MY` Malaysia · `TH` Thailand · `PH` Philippines · `VN` Vietnam
`year`	integer	optional	Year to query. Default: current year. Available: `2025`, `2026`.

Holiday types

Type	Meaning
`national`	Hari Libur Nasional — official national public holiday
`joint_leave`	Cuti Bersama — government-declared joint leave days (widely followed by private sector)

Example request

curl "https://apibase.dev/v1/holidays?country=ID&year=2026" \
     -H "X-Api-Key: sk_live_your_key"

Example response

{
  "country":  "ID",
  "year":     2026,
  "count":    25,
  "holidays": [
    { "date": "2026-01-01", "name": "Tahun Baru Masehi",              "type": "national"    },
    { "date": "2026-01-16", "name": "Isra Mikraj Nabi Muhammad SAW",  "type": "national"    },
    { "date": "2026-02-16", "name": "Cuti Bersama Tahun Baru Imlek",  "type": "joint_leave" },
    // ... 22 more entries
  ],
  "quota": { "used": 1, "limit": 10000, "remaining": 9999 }
}

Language Codes

Pass the code via ?lang=. Default is id.

Code	Language	1500000 →
id	Indonesian	satu juta lima ratus ribu
en	English	one million five hundred thousand
ms	Malay	satu juta lima ratus ribu
zh	Chinese (Simplified)	一百五十万
ja	Japanese	百五十万
ko	Korean	백오십만
ar	Arabic	مليون خمسمئة ألف
hi	Hindi	पंद्रह लाख
ru	Russian	один миллион пятьсот тысяч
de	German	eine Million fünfhunderttausend
fr	French	un million cinq cents mille
es	Spanish	un millón quinientos mil
pt	Portuguese	um milhão e quinhentos mil
it	Italian	un milione cinquecentomila
nl	Dutch	één miljoen vijfhonderdduizend
sv	Swedish	en miljon femhundratusen
tr	Turkish	bir milyon beşyüzbin
th	Thai	หนึ่งล้านห้าแสน
vi	Vietnamese	một triệu năm trăm nghìn