REST API · No infrastructure required

Fuzzy match
messy data with a
single API call

Send two arrays. Get back fuzzy matches, deduplication clusters, and similarity scores — from 10 records to 10 million. No pipeline to build. No infrastructure to maintain.

2 endpoints·10M+ records, same call·Any HTTP environment
reconcile.py
# Match your CRM leads against master database
import requests

r = requests.post("https://api.similarity-api.com/reconcile",
    headers={"Authorization": f"Bearer {API_KEY}"},
    json={
        "data_a": ["Microsft Corp", "apple inc"],
        "data_b": master_db,
        "config": {
            "similarity_threshold": 0.75,
            "to_lowercase": True,
            "use_token_sort": True
        }
    }
)
↳ Response
"Microsft Corp""Microsoft Corporation"0.94
"apple inc""Apple Inc."1.00

Used by teams doing data work including

Data EngineersRevOps & GTM teamsCRM ConsultantsData AgenciesETL Pipelines

The Problem

Works fine at 1,000 rows.
Breaks at 100,000.

Matching a few hundred records? Any approach works. Once you cross 100K rows, every in-house solution starts collapsing under its own weight.

📈

Pairwise comparison doesn't scale

Naive fuzzy matching is O(n²). At 1M records, that's trillions of comparisons — hours of CPU, gigabytes of memory, and a job that times out before it finishes.

🔧

You maintain more than you ship

Normalization preprocessing, blocking strategies, threshold tuning, algorithm selection — every project reinvents the same plumbing. It's not your core product.

🔒

Locked to one language and stack

Open-source matching libraries are Python-only. The moment your pipeline runs in Go, Java, a Salesforce flow, or an n8n automation — you're on your own.

The Alternative

Ship fuzzy matching
without the fuzzy pipeline

Everything you'd have to build and maintain yourself — replaced by a single POST request.

Build it yourself

⚙️Design & algorithm selection
Preprocessing & normalization
🧱Blocking strategy (for scale)
📊Scoring & threshold tuning
🔽Filtering & candidate ranking
📁Output formatting

Pipeline to build, test, and maintain

VS

Call Similarity API

Similarity API

1 API Call
One integration
Scales automatically
No maintenance
Any HTTP environment
GCP bucket input for very large datasets

Performance at Scale

The gap isn't linear.
It's exponential.

Anyone can match small datasets. The question is what happens at a million rows.

1,000×
faster than TheFuzz at 1M records
300×
faster than RapidFuzz at 1M records
422s
to process 1M rows vs. 130,000s+ for others

Same hardware. Representative datasets. Full methodology available.

Processing Time (seconds)
10K100K1M200K400K468Ks394Ks130Ks0.8s59s422sSimilarity APIRapidFuzzTheFuzzpython-Levenshtein

What Happens to Your Data

Noisy input.
Clean output.

Real-world records are inconsistent — casing, punctuation, word order, missing suffixes. The API scores similarity at the character level and groups records that refer to the same entity, however they were written.

Works the same whether you're deduplicating a single list or reconciling two datasets against each other.

How It Works

Two endpoints.
Every data matching problem.

Deterministic, explainable similarity scoring — stable across runs, tunable with clear parameters.

/reconcile

POST

Match records in Dataset A against a reference Dataset B. One call handles two strings or two million — same API, same parameters.

  • CRM lead matching against master account list
  • Vendor name reconciliation across ERP systems
  • Product catalog linkage without clean IDs
  • Fuzzy JOIN between datasets from different sources

/dedupe

POST

Find near-duplicate records within a single dataset. Returns pairs, clusters, or a clean deduplicated list — your choice of output format.

  • Clean contact lists before CRM import
  • Detect duplicate company or supplier records
  • Identify re-registrations in signup flows
  • Content deduplication in knowledge bases

Tunable parameters on every request: set a similarity_threshold, control preprocessing ( to_lowercase, remove_punctuation, use_token_sort ), strip common business entity suffixes and prefixes (Inc., Corp., Ltd., LLC, and more), and choose output format. Results are deterministic — same input always returns the same scores.

Use Cases

The same problem
across every industry

Anywhere humans type names into fields, you need fuzzy matching.

CRM Deduplication

Clean contact and account records before import. Catch "Microsoft Corp", "Microsoft Corporation", and "MSFT" as the same entity.

Data Reconciliation

Link records across two systems that share no common ID — supplier names in your ERP vs your finance system.

Product Catalog Matching

Match incoming vendor SKUs against your master catalog. Handle abbreviations, missing punctuation, and word-order differences.

KYC & Compliance

Screen entity names against watchlists and sanction databases where name variants, transliterations, and abbreviations abound.

Lead Routing & Enrichment

Match inbound leads against your CRM before creating new records. Stop sales reps from contacting the same company twice.

ETL & Data Pipelines

Add fuzzy matching as a step in your ingestion pipeline without spinning up additional infrastructure or managing Python dependencies.

Built For

Works for your team,
in your stack

For practitioners wiring systems together — whether that's code, a cloud pipeline, or a no-code automation.

Data Engineers

Drop fuzzy matching into Airflow, Databricks, or any cloud pipeline as a plain HTTP step. No Python dependency, no blocking logic, no infra.

GTM & RevOps Engineers

Call directly from HubSpot workflows or Salesforce Flow. Match inbound leads, dedup contacts, and route accounts — without leaving your CRM.

CRM & Data Consultants

Deliver cleaner migrations and reconciliation projects faster — without rebuilding matching scripts from scratch for every client engagement.

If it speaks HTTP, it works

Automation

  • n8n
  • Zapier
  • Make
  • Workato

CRM & RevOps

  • Salesforce Flow
  • HubSpot Workflows
  • Pipedrive
  • Zoho CRM

Data & Cloud

  • Databricks
  • AWS Lambda
  • GCP Functions
  • Azure Data Factory

Orchestration

  • Apache Airflow
  • Prefect / Dagster
  • dbt (via hooks)
  • Any REST client

In no-code tools: use any HTTP Request node — POST, Bearer token, JSON body. No plugin needed.

Copy-Paste Ready

Works in your language,
in your stack

One REST call. Structured JSON response. Node, Python, Go, Java — all covered in the docs.

Stop rebuilding the same pipeline

Your first match in

under 5 minutes

Free API key. No credit card. Copy the curl command from the docs and you're matching records before your coffee gets cold.