Normalize inflected words back to their dictionary forms.
Text Lemmatizer reduces inflected words in submitted text down to their dictionary base forms. It confirms when valid lemmas exist, while paid plans return full word-by-word mappings.
Try it — live request, no key required
No key required to try it. Get a key to use it in your app.
{
"status": "ok",
"error": null,
"data": {
"found": 3,
"lemmas": {
"cat": 1,
"ran": 1,
"door": 2
}
}
}
About the Text Lemmatizer API
Lemmatizer works by analyzing the text provided and lemmatizing it. It uses advanced algorithms to lemmatize the text and returns the lemmatized text.
What people use it for
- Search Query Normalization
- Search engines convert user queries into root words to match plural or conjugated variations against indexed product titles.
- Customer Feedback Clustering
- Group incoming support tickets by topic after reducing verbs and nouns to base forms for cleaner text classification.
- Vocabulary Learning Systems
- Language learning platforms detect inflected verb forms across reading exercises and map them back to headwords in student flashcards.
- SEO Content Auditing
- Before scanning articles for keyword density, content marketing platforms strip grammatical suffixes to measure true term frequencies across drafts.
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
- GraphQL
- Query language
- MCP
- For AI agents
Other ways to use Text Lemmatizer
Same data, same APIVerve account, same credit balance — one key works on all of them.
How many texts does the Free plan cover?
Can I get the word-by-word lemma mappings on the Free plan?
Can I submit full sentences or multi-word passages?
How are lemmatized words organized in the response?
What natural language processing tasks is this tool suited for?
Request parameters — POST /v1/lemmatizer
Sent as JSON in the request body. 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
| Parameter | Type | Example | Description |
|---|---|---|---|
textRequired | string | The dogs were running and jumping over the fences | The text to lemmatize |
curl -X POST "https://api.apiverve.com/v1/lemmatizer" \
-H "x-api-key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"text":"The cats ran from door to door"}'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.
| Header | When | Value |
|---|---|---|
x-api-keyRequired | Every request | Your API key. Header names are case-insensitive, so X-API-Key is the same header. |
AuthorizationAlternate | Instead of the above | Bearer <key> — for clients that only expose bearer auth. Resolves to the same account and the same billing. |
content-typeRequired | POST body | application/json |
A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.
Response — POST /v1/lemmatizer
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.
{
"status": "ok",
"error": null,
"data": {
"found": 3,
"lemmas": {
"cat": 1,
"ran": 1,
"door": 2
}
}
}
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.
| Field | Type | Example | Description |
|---|---|---|---|
found | number | 3 | The number of lemmas found in the input text |
lemmasPremium | object | {...} | Each word in the text mapped to its lemma, keyed by the word as it appeared |
catPremium | number | 1 | |
ranPremium | number | 1 | |
doorPremium | number | 2 |
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.
| Header | What it carries |
|---|---|
x-api-remaining-credits | Credits left in the current cycle |
x-api-credits-used | Credits spent in the current cycle |
x-api-max-credits | The allowance for the cycle |
x-api-version | Version of the endpoint that answered |
Errors
Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.
| Status | Meaning | What to do |
|---|---|---|
400 | Input was rejected | Read error; it names the parameter that has to change. |
401 | Key missing or invalid | Check the header name and the key value. |
403 | Key valid, but not permitted here | A key restriction or an IP allow-list — never a bad key. |
429 | Rate limited, or out of credits | Read error to tell them apart, then back off or top up. |
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.
| Plan | Per month | Credits | Text Lemmatizer calls | Per 1,000 calls |
|---|---|---|---|---|
| Free | Free | 200 | 100 | Free |
| Starter | $29.99 | 200,000 | 100,000 | $0.30 |
| Pro | $99.99 | 1,000,000 | 500,000 | $0.20 |
| Mega | $299.99 | 4,000,000 | 2,000,000 | $0.15 |
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.
Call it from cURL — POST /v1/lemmatizer
No SDK to install — this is a plain HTTPS call to /v1/lemmatizer with your key in the x-api-key header. Swap in a real key and it runs as-is.
curl "https://api.apiverve.com/v1/lemmatizer" \
-H "x-api-key: YOUR_API_KEY"Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Node.js — POST /v1/lemmatizer
Install the Node.js SDK, then call the Text Lemmatizer API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
npm install @apiverve/lemmatizerconst res = await fetch("https://api.apiverve.com/v1/lemmatizer", {
headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Python — POST /v1/lemmatizer
No SDK to install — this is a plain HTTPS call to /v1/lemmatizer with your key in the x-api-key header. Swap in a real key and it runs as-is.
import requests
res = requests.get(
"https://api.apiverve.com/v1/lemmatizer",
headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from C# / .NET — POST /v1/lemmatizer
Install the C# / .NET SDK, then call the Text Lemmatizer API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
dotnet add package APIVerve.API.TextLemmatizerusing var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");
var json = await client.GetStringAsync("https://api.apiverve.com/v1/lemmatizer");
Console.WriteLine(json);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Go — POST /v1/lemmatizer
No SDK to install — this is a plain HTTPS call to /v1/lemmatizer with your key in the x-api-key header. Swap in a real key and it runs as-is.
req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/lemmatizer", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from PHP — POST /v1/lemmatizer
No SDK to install — this is a plain HTTPS call to /v1/lemmatizer with your key in the x-api-key header. Swap in a real key and it runs as-is.
$ch = curl_init("https://api.apiverve.com/v1/lemmatizer");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);
$response = curl_exec($ch);
echo $response;Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Ruby — POST /v1/lemmatizer
No SDK to install — this is a plain HTTPS call to /v1/lemmatizer with your key in the x-api-key header. Swap in a real key and it runs as-is.
require "net/http"
uri = URI("https://api.apiverve.com/v1/lemmatizer")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.bodyResources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Zero-code embed — one snippet, no backend
Drop an interactive Text Lemmatizer 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 — Text Lemmatizer 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.
Entries are picked up from dated catalog snapshots, so the first one appears after the next snapshot that moves something. A period where nothing changed produces no entry — silence is a valid changelog for the Text Lemmatizer API.
Text Processing
- Acronym Expander
- Anagram Detector
- Antonym Finder
- Cron Expression Parser
- Data Masking
- Did You Mean
- Emoji Decorator
- Gibberish Detector
- Grammar Check
- ISBN Validator
- JSON Schema Validator
- Keyword Extractor
- Leet Speak
- Levenshtein Distance
- Line Sorter
- Markdown Link Extractor
- Palindrome Checker
- Parts Of Speech
- Phonetic Encoder
- Pig Latin
- Profanity Filter
- Reading Time Calculator
- Regex Tester
- Remove Punctuation
- Reverse Text
- Rhyming Words
- Slugify
- Spell Checker
- Syllable Counter
- Tax ID Validator
- Tense Converter
- Text Language
- Text Lemmatizer
- Text Readability Score
- Text Similarity
- Text Styler
- Text Summarizer
- Text to Emoji
- Title Case Converter
- Translator
- Vowel Counter
- Website Readability
- Word Lexicon Analyzer
- Word Opposites
- Word Pronunciation