MurmurHash API

About the MurmurHash API

A MurmurHash API that returns MurmurHash3 values for any text, in the 32-bit or 128-bit variant, with an optional seed. Send a string and get back the hash as a number and as a lowercase hex string, so you can compare it with what your own code, database or data pipeline produces.

MurmurHash is fast and spreads keys evenly, which is why it sits behind hash tables, bloom filters, sharding keys and sampling buckets. Not suitable for cryptographic purposes - use for data structures, deduplication, consistent hashing, and other performance-critical applications where the goal is distribution rather than secrecy. It is also handy for checking that two systems agree on a hash, or for computing bucket assignments in a no-code tool that has no hashing function of its own.

Every plan, including the Free plan, returns the full result for both variants. Change the seed to get an independent hash family from the same input, which is how bloom filters and count-min sketches derive several hash functions from one algorithm.

How it works

MurmurHash implements MurmurHash3 in two forms. variant=32 (the default) is MurmurHash3_x86_32; variant=128 is MurmurHash3_x86_128, transcribed from Austin Appleby's reference code. Any variant other than 32 produces the 128-bit hash.

The text you POST is hashed one byte per character, taking the low eight bits of each JavaScript character code. For ASCII text this is identical to hashing the UTF-8 bytes, so results match standard MurmurHash3 implementations. For characters outside ASCII it is not: an accented letter or emoji contributes only the low byte of its code, so hashes of non-ASCII text will not match a library that hashes UTF-8. Encode such input, for example as hex or Base64, before comparing across systems.

seed is parsed as an integer and defaults to 0. The same text and seed always give the same hash, and changing the seed gives an unrelated value.

For the 32-bit variant, hash is the result as an unsigned integer from 0 to 4,294,967,295, and hashHex is the same value as eight hex digits, zero-padded. For the 128-bit variant both hash and hashHex contain the same 32-character hex string, because the value is too large to return as a JSON number. It is the four 32-bit state words in order, each written in little-endian byte order. variant is returned as murmur3_32 or murmur3_128, and seed echoes the seed used. There is no plan-based difference in the output.

What people use it for

Hash Tables

Generate keys for hash-based data structures

Data Partitioning

Consistently distribute data across shards

Bloom Filters

Fast hashing for probabilistic data structures

Deduplication

Quickly identify duplicate records

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 — POST /v1/murmurhash

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

Optional

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curl -X POST "https://api.apiverve.com/v1/murmurhash" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"hello world","seed":0,"variant":"32"}'

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 — POST /v1/murmurhash

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": {
    "hash": 1586663183,
    "hashHex": "5e928f0f",
    "variant": "murmur3_32",
    "seed": 0
  }
}

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 — 1 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 MurmurHash 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 — MurmurHash 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