Phonetic Encoder API

About the Phonetic Encoder API

A phonetic encoder API with Soundex and Metaphone for matching words by how they sound rather than how they are spelled. Compare two words to check if they sound alike, or encode individual words for database indexing and search applications. Essential for name matching, spell checking, and genealogical research.

Encoding a word returns its Soundex code, its Metaphone code, or both. Comparing two words returns each word's codes and a match flag per algorithm, so "Smith" and "Smythe" can be recognized as the same name in a customer list. Store the codes next to your records and you get fuzzy name matching with a plain equality lookup, which is how sounds-alike search works in CRMs, record linkage, census and family-history data.

Soundex is coarse and forgiving, while Metaphone follows more English pronunciation rules; returning both lets you choose the trade-off per use. Every field is available on every plan, including the Free plan.

How it works

Phonetic Encoder implements both algorithms directly. Each word is trimmed, uppercased and stripped of everything except A to Z before encoding, so digits, spaces, apostrophes and accented letters are dropped. A word with no letters left encodes to an empty string.

Soundex keeps the first letter and maps the remaining consonants to digits: B F P V to 1, C G J K Q S X Z to 2, D T to 3, L to 4, M N to 5 and R to 6. Adjacent letters with the same digit collapse into one. Vowels and Y separate repeats, so the second P in "Pepper" is still coded, while H and W do not, so "Ashcraft" encodes as A261. The code is padded with zeros or cut to exactly four characters.

Metaphone applies English spelling rules and has no fixed length. It drops the silent first letter of KN, GN, PN, AE and WR, turns WH into W and an initial X into S, keeps a vowel only when it is the first letter, and maps letter groups to sounds: PH to F, a C before I, E or Y to S, CH and SH to X, TH to 0 (theta), DGE to J. Repeated letters other than C are skipped. "Smith" and "Smythe" both encode as SM0.

algorithm is soundex, metaphone or both (the default) and controls which codes are returned. Passing compare switches to comparison mode: word1 and word2 echo the trimmed inputs, and soundex and metaphone become objects holding word1Code, word2Code and a boolean match that is true when the two codes are identical. The response is identical on every plan.

What people use it for

Name Matching

Find similar names despite spelling variations

Search Enhancement

Improve search results with phonetic matching

Data Deduplication

Identify duplicate records with name variations

Genealogy Research

Match historical records with spelling variations

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON

Default REST response

XML

Markup format

YAML

Human-readable

CSV

Tabular export

Beta

GraphQL

Query language

New

MCP

For AI agents

Request parameters — GET /v1/phonetic

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Optional

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curl "https://api.apiverve.com/v1/phonetic?word=smith&algorithm=both" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Response — GET /v1/phonetic

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

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{
  "status": "ok",
  "error": null,
  "data": {
    "word": "smith",
    "soundex": "S530",
    "metaphone": "SM0"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

What a call costs — 2 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Zero-code embed — one snippet, no backend

Drop an interactive Phonetic Encoder form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.

Changelog — Phonetic Encoder API

Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.

Currently v1