API Ninjas for AI agents

API Ninjas offers a large catalog of small, single-purpose utility APIs, covering everything from currency conversion to text analysis, aimed at developers who need real data for real applications. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.

Connect API Ninjas See the 129 actions ↓

Developer toolsAPI keyMCP + RESTapi-ninjas.com

AUDIT LOG · API NINJASPOLICY: acme-support

09:41:07 · claude · u_8f2read

api_ninjas.get_gdp

Get GDP Data✓ allowed · 212ms

09:41:08 · claude · u_8f2read

api_ninjas.get_cars

Get Car Specifications✓ allowed · 164ms

09:41:09 · claude · u_8f2write

api_ninjas.bitcoin

Get Bitcoin Price and Market Data✓ approved · approved by user

EVERY API NINJAS CALL, ON THE RECORD

01 · USE CASES

What agents do in API Ninjas.

Check if a date is a holiday

Confirm whether a given date is a recognized holiday before scheduling around it.

Convert currency or units

Convert an amount between currencies or a value between measurement units for a calculation.

Look up crypto or bitcoin price

Pull the current price and market data for bitcoin or another cryptocurrency.

02 · ACTIONS

129 API Ninjas actions, graded by risk.

Every API Ninjas action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.

read

102

Look things up. Allowed by default.

api_ninjas.get_gdp
Get GDP Data
api_ninjas.get_cars
Get Car Specifications
api_ninjas.get_cats
Get Cat Breed Information
api_ninjas.get_city
Get City Information
api_ninjas.get_dogs
Get Dog Breed Information
api_ninjas.get_emoji
Get Emoji Information
api_ninjas.get_facts
Get Random Facts
api_ninjas.get_jokes
Get Random Jokes
api_ninjas.get_stars
Get Star Information
api_ninjas.get_whois
Get WHOIS Information
api_ninjas.get_advice
Get Random Life Advice
api_ninjas.get_county
Get County Information
api_ninjas.get_quotes
Get Random Quotes
api_ninjas.get_recipe
Get Recipe
api_ninjas.get_rhymes
Get Rhyming Words
api_ninjas.get_ticker
Get Ticker

+ 86 MORE

write

Create and change things. Allow, or ask the user first.

api_ninjas.bitcoin
Get Bitcoin Price and Market Data
api_ninjas.etf_info
ETF Info
api_ninjas.inflation
Get Inflation Data
api_ninjas.nutrition
Extract Nutrition Information
api_ninjas.bin_lookup
BIN Lookup
api_ninjas.dns_lookup
DNS Lookup
api_ninjas.market_cap
Market Cap
api_ninjas.iban_lookup
IBAN Lookup
api_ninjas.crypto_price
Crypto Price
api_ninjas.solve_sudoku
Solve Sudoku Puzzle
api_ninjas.interest_rate
Interest Rate
api_ninjas.mortgage_rate
Mortgage Rate
api_ninjas.commodity_price
Commodity Price
api_ninjas.generate_sudoku
Generate Sudoku Puzzle
api_ninjas.barcode_generate
Generate Barcode Image
api_ninjas.filter_profanity
Filter Profanity from Text

+ 11 MORE

destructive

Delete, cancel or archive. Ask first, or deny outright.

No destructive actions.

03 · HOW IT WORKS

API Ninjas in three steps.

01Your users connect API NinjasThey add their API Ninjas api key on Arc0 Connect, under your brand. It goes straight into the vault.
02You set the rulesReads run, and writes like “get Bitcoin Price and Market Data” can wait for the user to approve.
03Any agent can actYour agent calls API Ninjas through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.

POLICY.TS

await arc0.policies.set('api_ninjas', {
  read: 'allow',
  write: 'ask',        // bitcoin
  destructive: 'deny',  
})

# Claude Code: the same connection, one URL
$ claude mcp add --transport http arc0 \
    https://mcp.arc0.ai/u/u_8f2

04 · AUTH AND DATA

How API Ninjas connects.

Users add their API Ninjas api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

The same API Ninjas connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →

AUTH: API key
CREDENTIALS: Per-tenant encrypted vault
MODEL SEES: Results only, never credentials
AUDIT LOG: Every call, on every plan

05 · WORKS WITH

Use API Ninjas from any agent.

Claude

ChatGPT

Cursor

Codex

VS Code

OpenAI Agents SDK

Claude Agent SDK

Vercel AI SDK

Mastra

LangGraph

06 · RELATED

More developer tools apps.

Addressfinder17 actions

Addresszen2 actions

Alchemy36 actions

ALL DEVELOPER TOOLS APPS →

07 · FAQ

API Ninjas and Arc0, answered.

Q01

Can I use API Ninjas with Claude, ChatGPT or Cursor?

Yes. Connect API Ninjas to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the API Ninjas actions you allow.

Q02

How do users connect API Ninjas?

Users add their API Ninjas api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

Q03

Which API Ninjas actions can my agent take?

129 in total: 102 read, 27 write and 0 destructive, such as “get Bitcoin Price and Market Data”. Your policies decide which of them each agent may call.

Q04

Can I make my agent read-only in API Ninjas?

Yes. Allow read actions and deny writes in the API Ninjas policy. Your agent can still look things up, and any write it attempts is blocked and logged.

Q05

Can my own backend call API Ninjas too?

Yes. The same API Ninjas connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.

Get started

Plug API Ninjas into your agent.

Your users connect API Ninjas once, under your brand. Your agent gets 129 actions behind your policies, with every call on the record.

Connect API Ninjas Browse all apps →

Free to build · MCP + REST · Audit log on every plan