Fixer.io for AI agents

Fixer.io provides current and historical foreign exchange rates and currency conversion through a lightweight API, used by applications that need to display prices in local currency. 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 Fixer.io See the 5 actions ↓

Developer toolsAPI keyMCP + RESTfixer.io

AUDIT LOG · FIXER.IOPOLICY: acme-support

09:41:07 · claude · u_8f2read

fixer_io.get_fluctuation

Get Currency Fluctuations✓ allowed · 212ms

09:41:08 · claude · u_8f2read

fixer_io.get_time_series

Get Time Series✓ allowed · 164ms

EVERY FIXER.IO CALL, ON THE RECORD

01 · USE CASES

What agents do in Fixer.io.

Convert between currencies

Convert an amount from one currency to another for a quote shown to a customer.

Check currency fluctuations

Get fluctuation data for a currency pair over a period to explain a pricing change.

Read-only time series checks

Get a time series of rates as a read-only step before a finance team reviews trends.

02 · ACTIONS

5 Fixer.io actions, graded by risk.

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

read

Look things up. Allowed by default.

fixer_io.get_fluctuation
Get Currency Fluctuations
fixer_io.get_time_series
Get Time Series
fixer_io.get_historical_rates
Get Historical Rates
fixer_io.get_supported_symbols
Get Supported Symbols
fixer_io.convert_currency
Convert Currency

write

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

No write actions.

destructive

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

No destructive actions.

03 · HOW IT WORKS

Fixer.io in three steps.

01Your users connect Fixer.ioThey add their Fixer.io api key on Arc0 Connect, under your brand. It goes straight into the vault.
02You set the rulesReads run, and writes like “updates” can wait for the user to approve.
03Any agent can actYour agent calls Fixer.io 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('fixer_io', {
  read: 'allow',
  write: 'ask',        
  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 Fixer.io connects.

Users add their Fixer.io 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 Fixer.io 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 Fixer.io 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

Fixer.io and Arc0, answered.

Q01

Can I use Fixer.io with Claude, ChatGPT or Cursor?

Yes. Connect Fixer.io 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 Fixer.io actions you allow.

Q02

How do users connect Fixer.io?

Users add their Fixer.io 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 Fixer.io actions can my agent take?

5 in total: 5 read, 0 write and 0 destructive. Your policies decide which of them each agent may call.

Q04

Can I make my agent read-only in Fixer.io?

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

Q05

Can my own backend call Fixer.io too?

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

Get started

Plug Fixer.io into your agent.

Your users connect Fixer.io once, under your brand. Your agent gets 5 actions behind your policies, with every call on the record.

Connect Fixer.io Browse all apps →

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