Exchange rate APIs you can pay per call

What exchange rate APIs do

An exchange rate API returns the value of one currency in another. The simplest request asks for a rate between two currencies; a conversion request adds an amount and returns the converted total. An agent uses it to show prices in a buyer's currency, total a multi-currency invoice, value a past payment or watch a currency it is exposed to.

Rates are not all the same kind of number. A reference rate is published by a central bank or an aggregator, often once per working day, and is meant for statistics, accounting and information. A dealing quote is the price a bank, broker or liquidity provider is offering at a moment, usually as a bid and an ask. A street or parallel rate describes a market outside the official one where it exists. Each answers a different question, and mixing them in one column produces numbers that cannot be compared.

Time is part of every rate. A daily reference rate carries a reference date, and a request made on a Sunday may return Friday's value. A live quote carries a timestamp in seconds. A historical request should name the date of the transaction it values. Store the date with the rate, because a conversion repeated tomorrow with the same inputs can give a different total.

A rate from an API is information, not a promise. Providers can label their rates indicative, cache them for a period or derive cross rates through the euro or the dollar. When money actually changes hands, the bank or payment provider applies its own rate and fees. Use API rates to estimate, display and reconcile, and keep the provider's own caveats with the result.

Compare the returned data, scope and limitations

The latest type covers routes that return a current or latest published fiat rate, with or without an amount conversion. The historical type covers rates for a chosen past date or a series over time. Both can qualify a service. A route can belong to both when it returns today's rate and a recent series in one response.

Bid and ask routes return two sides of a quote, or the buying and selling rates a bank publishes. Street-rate routes describe a parallel market derived from other sources. Both stay separate from the latest-rate quote: a cheaper street rate cannot stand in for an official reference, and a spread changes the meaning of the number.

Wider products can include a rate among other data. A travel bundle, a country snapshot, a macro report or an invoice workflow can contain exchange rates without being a rate lookup. They stay adjacent and cannot qualify a service or set its row price. Crypto prices and currency lists stay out of the task even when they share words with it.

Vibe Springs, AgentBIT, x402node, Soren, Busker, Ni Biashara — Africa FX & services for agents, Polyform, DYOE Agent Services, Datakoot, AgentShop and Premium Rewards data GETs name ECB reference rates or Frankfurter in matched descriptions. Losbeto — LLM Gateway & Market Intelligence, zaref, POKT Agent — Korea data & checks for AI agents and SENTINEL Compliance Intelligence name another central bank or official fixing. Losbeto — LLM Gateway & Market Intelligence and SuVerse Pay name ExchangeRate-API, and Ni Biashara — Africa FX & services for agents name Bybit P2P order books for a street rate. A named source is the provider's statement; check the reference date the response returns.

Each price is the cheapest endpoint of that service for that kind of data: the same number wherever this page quotes it.

Compare 20 exchange rate services

Each row keeps the selected rate endpoint and its reference price. The order follows observed paying wallets for the service; it does not rank the accuracy of the rates.

$/CALL is the price of the endpoint named under it: the cheapest current or latest published fiat rate, with or without conversion and reference rate for a past date or a time series endpoint of the service or, for a service without one, its cheapest exchange rate endpoint. Never the cheapest tool of a gateway. Other kinds of data have their own price in the tables below. EXCHANGE RATE ENDPOINTS counts the exchange rate endpoints out of all the endpoints the service lists. BUYERS 30D counts distinct wallets that paid the whole service on-chain in 30 days, not only its exchange rate endpoints. "Generalist" marks a gateway that sells more than three unrelated kinds of tools: it is never called the cheapest.

How to choose an exchange rate endpoint

Decide which rate you need

Displaying an approximate price, closing the books at month end, valuing a payment on its date and pricing a trade need different rates. Write down whether you need a daily reference, a past date, a live quote or a regional official rate before comparing routes.

Check the currencies and the base

A route built on ECB reference rates covers the currencies the ECB publishes and derives other pairs through the euro. A regional route covers the currencies of its region. A dollar-based set can list many more currencies with a different source. Confirm that both currencies of your pair are covered directly or say how the cross rate is built.

Keep the reference date and source

Store the rate, the reference date or timestamp, the source and the route with every conversion. Without them, a later audit cannot tell a stale rate from a live one or explain why two systems converted the same amount differently.

Read the caveats

A provider can state that a rate is indicative only and not for transactions, that a value is cached or that a cross rate is derived. Those statements matter more than the price of the call. Pass them on to whoever reads the converted amount.

Test the operating limits

The monitored median uptime is 100% and the median selected quote is $0.005. Monitoring latency describes our checks, not how fresh a rate is. Request a weekend date, an unsupported currency and a pair that needs a cross rate, and note how each route answers.

Choose by the output your workflow needs

Start with the rate your next step can use. The candidates below use the same type classification as the comparison table. Each quote belongs to the lowest priced endpoint of the requested types, with the path kept.

Convert a price at the latest rate

Store the rate, its reference date and the source with the converted amount. A reference rate published once a day is not a live dealing price, so label it as indicative wherever a customer sees it.

Candidates today, most buyers first: Tick Aggregator FX API ($0.005/call, 308 buyers) · Vibe Springs ($0.002/call, 140 buyers) · AgentBIT ($0.005/call, generalist, 71 buyers) · x402node ($0.004/call, 65 buyers) · Losbeto — LLM Gateway & Market Intelligence ($0.012/call, generalist, 32 buyers) · Soren ($0.01/call, 28 buyers) · SuVerse Pay ($0.05/call, generalist, 28 buyers) · zaref ($0.005/call, generalist, 14 buyers) · Busker ($0.001/call, generalist, 13 buyers) · Ni Biashara — Africa FX & services for agents ($0.01/call, 13 buyers) · Polyform ($0.003/call, generalist, 11 buyers) · GadgetHumans API ($0.002/call, 8 buyers) · DYOE Agent Services ($0.01/call, generalist, 8 buyers) · Datakoot ($0.01/call, generalist, 7 buyers) · SENTINEL Compliance Intelligence ($0.001/call, generalist, 5 buyers) · AgentShop ($0.001/call, generalist, 2 buyers) · Premium Rewards data GETs ($0.001/call, 2 buyers) · x402.eleeth.com ($0.01/call, generalist, 1 buyer) · AnT API — live market data for AI agents ($0.001/call)

Value a past transaction on its date

Ask for the date of the transaction, not the date of the request. Check how the route handles weekends and holidays, when no reference rate is published, and record which date the answer actually used.

Candidates today, most buyers first: Vibe Springs ($0.002/call, 140 buyers) · POKT Agent — Korea data & checks for AI agents ($0.005/call, generalist, 13 buyers) · Datakoot ($0.01/call, generalist, 7 buyers) · SENTINEL Compliance Intelligence ($0.001/call, generalist, 5 buyers)

Quote with a spread

Keep bid, ask and mid apart. An indicative spread from a reference feed and a best bid and ask from trading sources are different evidence, and neither is a price you can deal at.

Candidates today, most buyers first: Tick Aggregator FX API ($0.005/call, 308 buyers) · AgentBIT ($0.005/call, generalist, 71 buyers) · POKT Agent — Korea data & checks for AI agents ($0.005/call, generalist, 13 buyers) · SENTINEL Compliance Intelligence ($0.001/call, generalist, 5 buyers)

Track a street rate next to the official one

A street rate is derived from a market the official rate does not cover. Keep its method, source and capture time with every value, and never put it in the same field as the official reference.

Candidates today, most buyers first: Ni Biashara — Africa FX & services for agents ($0.05/call, 13 buyers)

What the providers describe

These paragraphs attribute output contracts and limits to each provider. Reference prices follow the matching endpoint type rather than an amount written in a marketing description.

Datakoot

Datakoot lists separate rate routes. /api/fx_rates describes the latest rates for a base currency, /api/fx_convert converts an amount at the latest ECB reference rate, /api/fx_historical returns rates for a past date and /api/fx_timeseries returns a range of up to about a year. The latest-rate quote starts at $0.01 and the historical quote at $0.01. A currency list on the same host returns names, not rates, so it does not set either quote. The provider says calls are charged only on success; check your own result records before relying on that.

4 exchange rate endpoints of 48 · $0.01/call (GET /api/fx_convert) · Base · uptime 30d 100% · 86 ms · 7 buyers in 30 days

Tick Aggregator FX API

Tick Aggregator describes /tick/latest and /tick/all as best bid and ask for FX pairs aggregated, in its words, from multiple institutional liquidity sources, with quality metadata such as the number of fresh sources. Its bid and ask quote starts at $0.005. The provider claims tighter spreads than any single source; that is its own measurement. A best bid and ask is a market quote at a moment, not a reference rate for accounting, and the provider lists 14 instruments, including gold against the dollar.

2 exchange rate endpoints of 3 · $0.005/call (GET /tick/all) · Base/SOL · uptime 30d 100% · 266 ms · 308 buyers in 30 days

Ni Biashara — Africa FX & services for agents

Ni Biashara separates official and street rates for African currencies. Its official routes return rates against the dollar via Frankfurter, and the description itself says the number is a blend of published central-bank reference rates rather than a single central bank's fixing; the official quote starts at $0.01. The street routes for naira and cedi are derived from Bybit's public P2P order books, with hourly history from the provider's own archive, and start at $0.05. A street rate is the provider's derived estimate of a market the official rate leaves out; keep both side by side rather than replacing one with the other.

6 exchange rate endpoints of 22 · $0.01/call (GET /shelf/fx-official) · Base · uptime 30d 100% · 278 ms · 13 buyers in 30 days

Soren

Soren describes /v1/oracle/fx as a signed, timestamped ECB reference rate for any pair among the currencies the ECB publishes. The response is said to include the ECB reference date, the underlying euro rates, a SHA-256 hash of the returned bytes and an Ed25519 signature. Its quote starts at $0.01. A signature proves which bytes the provider returned; it does not make a daily reference rate live, so the reference date still decides how the number can be used.

1 exchange rate endpoint of 9 · $0.01/call (GET /v1/oracle/fx) · Base · uptime 30d 100% · 239 ms · 28 buyers in 30 days

AgentBIT

AgentBIT describes /v1/finance/fx as live rates for one or many pairs with mid, indicative bid and ask, source attribution, timestamp and confidence, derived from ECB reference rates and cached for 30 seconds. Its quote starts at $0.005. An indicative spread built around a reference rate helps display a range; it is not a dealing quote from a bank or broker. Keep the source and timestamp from the response with each converted amount.

1 exchange rate endpoint of 25 · $0.005/call (GET /v1/finance/fx) · ARB/Base/POL/SOL · uptime 30d 100% · 130 ms · 71 buyers in 30 days

Cost per call and for a larger workload

The median selected route costs $0.005 per call. At the same request shape, 100,000 calls total $500.00. Use the generated table as a reference calculation, then count how many lookups one finished task needs.

Each service at the price of its main exchange rate endpoint, the one named in the table above.

The number of calls depends on how rates are used. A daily reference rate changes once per working day, so a cached value can serve many conversions on the same date. A route that returns every currency for a base in one call can replace many pair lookups. A live quote that must be fresh for every price shown needs far more calls. Keep the exact endpoint, parameters and quote with each result, so a cheap single-pair call is not mistaken for the cost of a full price list.

Set a budget per task and a rule for reusing a rate within its reference date. Separate an unsupported currency, a missing date and an unavailable upstream in the result record. The provider's terms decide whether those outcomes are charged. Read the payment challenge for the exact request before authorizing it, and do not estimate rate lookups from a gateway's cheapest unrelated tool.

Inspect a request and its payment evidence

For a conversion at the latest rate, Datakoot documents GET /api/fx_convert, with a latest-rate reference quote of $0.01. Read its current schema to pass the amount and both currencies, and verify that the response carries the rate and date your record needs.

The listed method and description establish the advertised contract. This explanation does not reproduce an HTTP 402 challenge or certify a paid response. Open the service page's payment evidence and obtain the challenge for the exact request before authorizing payment. Compare resource, method, input, network, asset and amount together; do not reuse a challenge from a neighboring historical or currency-list route.

How this comparison is built

The comparison starts with services that are online and payment-ready, have a known price, a description of at least 80 characters and measured 30-day uptime of at least 90%. Task selection then reads the documented endpoints. Currency or forex words in a service description can make a service a candidate without proving that a captured route returns a fiat exchange rate. A rate advertised in the description but missing from the captured endpoints is not quoted. Pages below the index threshold can still be read directly.

Provider claims were reviewed against the public service and endpoint descriptions captured on October 22, 2026. They remain provider claims. Monitoring supplies operating figures and reference prices; it does not check a rate against its official source. Buyer counts describe observed paying wallets for the service, with the coverage limits explained on its linked page.

The endpoint classification supplies the comparison quote, per-type prices and job candidates. A row needs a fixed quote for a latest or historical fiat rate. Bid and ask sides, street rates and wider reports remain adjacent types and cannot qualify a service on their own. Keep the named path when comparing services: an adjacent route can have a different input, unit and evidentiary value on the same host.

Questions

How to pay

Each service answers an unpaid call with HTTP 402 and its price; your agent signs a USDC payment on the listed network and retries. No API key, no account, no subscription. See what x402 is.