# RateSonar

> RateSonar is a point-in-time archive of advertised Australian bank rates.
> Each value has the day it was recorded. This file does not contain today's rates.
> Read a live endpoint, then cite that response.

Full manual, series list and worked calls: https://ratesonar.com/llms-full.txt

## MCP, no sign-up

MCP and HTTP: https://api.ratesonar.com

No account and no key. Anonymous series calls return the last 31 days (`windowClamped: true`).

```
{ "mcpServers": { "ratesonar": { "url": "https://api.ratesonar.com" } } }
```

## Rules an agent must keep

- Cite `observed_date` with every rate. A rate without that date is not a RateSonar answer.
- A point is `observed` (recorded that day), `carried-forward` (the last recorded rate repeated; it has `sourceDate` and `fill`), or `derived` (a median or a spread; it has `sourceDates`). Never call a carried-forward or derived point recorded.
- Do not invent a named bank or product rate for a day RateSonar did not record. Do not draw a continuous history before RateSonar's own capture in June 2026.
- Product identity is `(institutionId, productId)`. Never look up history by `productId` alone. If the API returns `ambiguous_product_id`, call again with `institutionId`.
- Series slugs (`hl.var.oo.pi`, `cash`) are not product ids. Take product ids from `compare_rates` or a bank page. Discover series slugs from `GET /v1/catalog`.
- Loans rank lowest rate first. Savings and term deposits rank highest rate first.
- The RBA cash series (`cash`) is the cash-rate target, not a quote from a bank. Monthly RBA market tables on the site are market context, not a lender's price.
- `GET /v1/intent` reads a search phrase. It never returns a rate.
- `POST /v1/ask` answers from recorded rows in code. It does not call a language model. It refuses questions that are not about these rates.
- RateSonar does not take applications, rank sponsored lenders, or give personal credit advice. Send the person to the lender for eligibility.

## How to answer

1. "What is the rate now" for a category: MCP `compare_rates`, or the matching page below. Cite each row's `observedDate`.
2. "What did this product do over time": `compare_rates` to get both ids, then `rate_history`. Pass `grid: true` only when you will label carried-forward days.
3. "Fees, tiers, offset, eligibility": `rate_details` with both ids.
4. "Who moved": `rate_changes` or `GET /v1/changes`.
5. "A standard series or a spread": `GET /v1/catalog`, then `GET /v1/series` or MCP `series`. Anonymous series calls return the last 31 days (`windowClamped: true`).
6. A typed phrase ("cheapest 2 year fixed for investors"): `GET /v1/intent?q=…` for the fields, then `compare_rates` with those fields. Intent is not the rate.

## Pages

- [Search](https://ratesonar.com/): type a bank, a loan or a question. `/?q=` restores the same search.
- [Home loans](https://ratesonar.com/home-loans): lowest advertised rate first.
- [Savings and term deposits](https://ratesonar.com/savings): highest advertised rate first.
- [Business loans](https://ratesonar.com/business-loans): lowest advertised rate first.
- [One bank](https://ratesonar.com/bank/cba): swap the slug (`anz`, `westpac`, `nab`, and the other lenders on the site).
- [What changed](https://ratesonar.com/changes): moves between consecutive records.
- [History](https://ratesonar.com/history): one chart per lender. A dashed span is carried forward.
- [About the data](https://ratesonar.com/about): sources, dates, limits.
- [Comparisons](https://ratesonar.com/compare): how RateSonar differs from Canstar, Finder and RateCity. Each page names its owner and the day it was checked. Do not copy a rate off those pages.
- [Corrections](https://ratesonar.com/cleanups): source-data fixes, with the reason.
- [API and MCP](https://ratesonar.com/api): how to connect.
- [API reference](https://ratesonar.com/api/docs): paths and how to read a point.
- [Pricing](https://ratesonar.com/pricing): free browsing. Paid plans are proposed. There is no live card checkout.
- [Privacy](https://ratesonar.com/privacy): what the site stores.

## API

The host and the no-key rule are at the top of this file.

- `compare_rates(category, asOf?, loanPurpose?, repaymentType?, rateType?, termMonths?, customerSegment?, audience?, limit?)` — MCP only. `category`: `home_loan`, `business_loan`, `savings`, `term_deposit`, `credit_card`, `personal_loan`, `car_loan`. Home-loan filters: `loanPurpose` `owner_occupied`|`investment`, `repaymentType` `pi`|`io`, `rateType` `variable`|`fixed`. Term deposits: `termMonths` (1–120). Deposits: `customerSegment` `consumer`|`business`. `audience` defaults to `standard`. `limit` defaults to 25, max 500. Loans lowest first. Deposits highest first.
- `rate_history(productId, institutionId?, from?, to?, grid?)` — MCP only. `grid: true` adds one labelled point per day, at most 367 days.
- `rate_details(institutionId, productId, asOf?)` — MCP only. Both ids required. Exact tiers, fees, features, eligibility, on or before `asOf`.
- `rate_changes(institutionId?, sinceDays?)` — MCP only. `sinceDays` default 14, integer 1–3650.
- `series(slugs, institutions?, median?, from?, to?)` — MCP only. Same points as HTTP `/v1/series`. Anonymous window is 31 days.
- `GET /v1/catalog` — live series list. Use this, not a remembered rate.
- `GET /v1/series?slugs=hl.var.oo.pi&institutions=cba&median=1` — levels in percent, spreads in basis points.
- `GET /v1/changes?since=YYYY-MM-DD&institution=cba` — change events. `truncated: true` means the window overflowed 1000 rows.
- `GET /v1/tiers` — plan names and history windows.
- `POST /v1/ask` body `{"question":"…"}` — up to five dated lines from recorded rows.
- `GET /v1/intent?q=…` — search fields and confidences. Never a rate. `q` max 120 characters.
- `GET /openapi.json` — HTTP paths only. It does not list the MCP tools.

There is no HTTP mirror of `rate_history`, `rate_details` or `compare_rates`.

## Coverage

Page captures of core bank and RBA sources run daily from 2026-06-12. CDR product listings run from 2026-06-14. Coverage still varies by lender and product. Say so when a series is short.

## Not this

- No personal loan applications, credit scores, or "you will be approved".
- No rate from before the first recorded day of that product.
- No treating a carried-forward day as proof the lender confirmed the price that day.
- Counts of lenders and products change. Read them on https://ratesonar.com . Do not quote a count from memory or from this file.