Text Similarity API POST

Documentation Start for free →

Text Similarity is a simple tool for checking the similarity between two texts. It returns the similarity score.

Try it — live request, no key required

Request

POSTapi.apiverve.com/v1/textsimilarity

Verification

Format

No key required to try it. Get a key to use it in your app.

200 OK

{
  "status": "ok",
  "error": null,
  "data": {
    // Text Similarity response payload
  }
}

About the Text Similarity API

Text Similarity works by comparing the two texts and calculating the similarity score based on various factors. It returns the similarity score in a structured format.

What people use it for

Plagiarism Detection: Use the Text Similarity API to check for plagiarism in texts. Use the data to identify duplicate content and prevent academic dishonesty
Content Analysis: Analyze content by using the Text Similarity API to check the similarity between texts. Use the data to compare articles, essays, and research papers
Document Comparison: Compare documents by using the Text Similarity API to check the similarity between texts. Use the data to find similarities and differences in text content
Text Matching: Match text by using the Text Similarity API to check the similarity between texts. Use the data to find related content and improve search results

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

View all integrations →

Other ways to use Text Similarity

Same data, same APIVerve account, same credit balance — one key works on all of them.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.on VerveKit Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.on VerveSheets

Questions.

Common questions about the Text Similarity API.

Read the docs →

What does the Text Similarity API do?

Text Similarity is a simple tool for checking the similarity between two texts. It returns the similarity score.

How do I authenticate Text Similarity API requests?

Pass your API key in the x-api-key header over HTTPS. One key works across all 300+ APIVerve APIs — there are no per-endpoint credentials.

How much does the Text Similarity API cost?

Each call spends 2 credits from your shared pool. The free tier includes 200 credits every month, and paid plans add more headroom.

How fast is the Text Similarity API?

Response time depends on the endpoint — the p50 through p99 latency for this API is published on this page. Requests are served over HTTPS through a global edge network.

What response formats does the Text Similarity API support?

JSON by default, plus XML and YAML via the format parameter. GraphQL and an MCP interface for AI agents are available across the catalog.

What HTTP method does the Text Similarity API use?

POST over HTTPS, following standard REST conventions with a consistent { status, error, data } response envelope.

Request parameters — POST /v1/textsimilarity

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
`text1`Required	string	`The quick brown fox jumps over the lazy dog`	The first text to compare. Must be less than 1000 characters
`text2`Required	string	`A fast brown fox leaps over a sleepy dog`	The second text to compare. Must be less than 1000 characters

Example request

curl -X POST "https://api.apiverve.com/v1/textsimilarity" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text1":"I'\''m so excited that tomorrow is going to be sunny! Can'\''t wait!","text2":"We'\''re pretty excited about the weather tomorrow. It'\''s going to be sunny!"}'

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-key`Required	Every request	Your API key. Header names are case-insensitive, so `X-API-Key` is the same header.
`Authorization`Alternate	Instead of the above	`Bearer <key>` — for clients that only expose bearer auth. Resolves to the same account and the same billing.
`content-type`Required	POST body	`application/json`

401 is the only auth verdict

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/textsimilarity

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.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "simiarity": 45.83,
    "similarityCaseSensitive": 47.22,
    "difference": {
      "count": 7,
      "percentage": 58.33
    }
  }
}

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
`simiarity`	number	`45.83`
`similarityCaseSensitive`	number	`47.22`
`difference`	object	`{...}`
`count`	number	`7`
`percentage`	number	`58.33`	Similarity percentage between 0 and 100

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 Similarity 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.

Compare all pricing tiers →

Call it from cURL — POST /v1/textsimilarity

No SDK to install — this is a plain HTTPS call to /v1/textsimilarity with your key in the x-api-key header. Swap in a real key and it runs as-is.

cURL

1
2

curl "https://api.apiverve.com/v1/textsimilarity" \
  -H "x-api-key: YOUR_API_KEY"

Resources

GitHubapiverve/textsimilarity-apiSource, issues and the examples this page is built from.ReferenceText Similarity API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/textsimilaritynpm apiverve-textsimilarityPyPI APIVerve.API.TextSimilarityNuGet

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/textsimilarity

Install the Node.js SDK, then call the Text Similarity API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — npm

npm install @apiverve/textsimilarity

Node.js

const res = await fetch("https://api.apiverve.com/v1/textsimilarity", {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);

Resources

npm@apiverve/textsimilarityThe published Node.js client, versioned and signed.GitHubapiverve/textsimilarity-apiSource, issues and the examples this page is built from.ReferenceText Similarity API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

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/textsimilarity

Install the Python SDK, then call the Text Similarity API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — PyPI

pip install apiverve-textsimilarity

Python

import requests

res = requests.get(
    "https://api.apiverve.com/v1/textsimilarity",
    headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])

Resources

PyPIapiverve-textsimilarityThe published Python client, versioned and signed.GitHubapiverve/textsimilarity-apiSource, issues and the examples this page is built from.ReferenceText Similarity API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/textsimilaritynpm APIVerve.API.TextSimilarityNuGet

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/textsimilarity

Install the C# / .NET SDK, then call the Text Similarity API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — NuGet

dotnet add package APIVerve.API.TextSimilarity

C# / .NET

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var json = await client.GetStringAsync("https://api.apiverve.com/v1/textsimilarity");
Console.WriteLine(json);

Resources

NuGetAPIVerve.API.TextSimilarityThe published C# / .NET client, versioned and signed.GitHubapiverve/textsimilarity-apiSource, issues and the examples this page is built from.ReferenceText Similarity API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/textsimilaritynpm apiverve-textsimilarityPyPI

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Go — POST /v1/textsimilarity

No SDK to install — this is a plain HTTPS call to /v1/textsimilarity 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/textsimilarity", 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

@apiverve/textsimilaritynpm apiverve-textsimilarityPyPI APIVerve.API.TextSimilarityNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from PHP — POST /v1/textsimilarity

No SDK to install — this is a plain HTTPS call to /v1/textsimilarity with your key in the x-api-key header. Swap in a real key and it runs as-is.

PHP

$ch = curl_init("https://api.apiverve.com/v1/textsimilarity");
curl_setopt($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

@apiverve/textsimilaritynpm apiverve-textsimilarityPyPI APIVerve.API.TextSimilarityNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Ruby — POST /v1/textsimilarity

No SDK to install — this is a plain HTTPS call to /v1/textsimilarity with your key in the x-api-key header. Swap in a real key and it runs as-is.

Ruby

require "net/http"

uri = URI("https://api.apiverve.com/v1/textsimilarity")
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.body

Resources

Also published for

@apiverve/textsimilaritynpm apiverve-textsimilarityPyPI APIVerve.API.TextSimilarityNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Text Processing

View all 45 →

All articles →

Take Your App Multilingual (No Rewrite)Add language support to an existing app without rearchitecting. Practical strategies for translation, detection, and localization.Read

Summarize Text with AI: A Practical GuideUse AI to summarize articles, documents, and user content. Tutorial with code for content platforms, research tools, and dashboards.Read

7 Content Moderation Mistakes That Sink AppsYour app allows user content. Here are the moderation mistakes that get apps pulled from stores.Read

Text Similarity API POST

Try it — live request, no key required

About the Text Similarity API

What people use it for

Ways to call it

Other ways to use Text Similarity

Questions.

Request parameters — POST /v1/textsimilarity

Required

Authentication

Response — POST /v1/textsimilarity

Response fields

Response headers

Errors

What a call costs — 2 credits per call

Call it from cURL — POST /v1/textsimilarity

Resources

Also published for

Call it from Node.js — POST /v1/textsimilarity

Resources

Also published for

Call it from Python — POST /v1/textsimilarity

Resources

Also published for

Call it from C# / .NET — POST /v1/textsimilarity

Resources

Also published for

Call it from Go — POST /v1/textsimilarity

Resources

Also published for

Call it from PHP — POST /v1/textsimilarity

Resources

Also published for

Call it from Ruby — POST /v1/textsimilarity

Resources

Also published for

Zero-code embed — one snippet, no backend

Changelog — Text Similarity API

Text Processing

Related articles

Ready to build with Text Similarity? Start with 200 free credits — one key unlocks all 300+ APIs.

Explore the catalog