The comparison, as JSON

The rates themselves are free

Every lender publishes its rates under the Consumer Data Right. That data is public. It is not mine, and I do not sell it. Download the whole set, rebuilt every night, free under CC BY 4.0.

What you pay for is the reading of it: the going rate, the fee allowance, which lenders this borrower could actually move to, and what to do about it. Plus who each loan is for, which no lender files and the CSV does not carry.

Fetching the files on a schedule

Checking for a new file costs nothing. Send the file's ETag back as If-None-Match (If-Modified-Since works as well) and, if nothing has changed, you get a 304 and no download. The files are rebuilt once a day, after the 19:30 UTC capture, so the other 287 times you ask today cost nothing on either side. Every page on this site answers the same way.

A call

curl -X POST https://rategap.com.au/v1/compare \
  -H "Authorization: Bearer YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "balance": 650000,
    "rate": 6.9,
    "years": 25,
    "propertyValue": 850000,
    "purpose": "OWNER_OCCUPIED",
    "repayment": "PRINCIPAL_AND_INTEREST"
  }'

Call it from your server. There is no CORS, on purpose: a key in a browser is a key anyone can read.

{
  "gapBand": "large_gap",
  "rate": {
    "paying": 6.9,
    "effective": 6.9,
    "feeState": "UNKNOWN",
    "benchmark": 6.0992,
    "anchor": 6.09,
    "feeAllowance": 0.0092,
    "surplus": 0,
    "belowAnchor": false
  },
  "gapPoints":      { "backBook": 0, "switching": 0.8008 },
  "dollarsPerYear": { "backBook": 0, "switching": 5204.78 },
  "ownLender": null,
  "market": { "pool": 118, "eligible": 96, "advertisedBelowYou": 91, "lowestAdvertisedEligible": 5.64 },
  "targets": [
    {
      "lender": "coral-coast",
      "lenderName": "Coral Coast Bank",
      "product": "Sharp Variable Home Loan",
      "rate": 5.64,
      "comparisonRate": 5.68,
      "annualFee": 0,
      "upfrontFees": 350,
      "conditions": [],
      "link": "https://example.com/rates"
    }
  ],
  "switchCosts": {
    "ownDischarge": null,
    "dischargeBand": [250, 500],
    "upfrontBand":   [250, 1930],
    "total":         [650, 2830]
  },
  "asOf": "2026-09-09T19:50:00Z"
}

Add ?include=lines to get the full rate table behind the answer. It is large. Most callers never need it.

Who each loan is for

One call. Every restricted product, and the lender's own words for why.

A lender does not file who may take a loan. The Consumer Data Right has a field for it, and it is boilerplate: across 312 sampled products it said OTHER 399 times, and one lender files its first-home-buyer rule under STAFF.

So the real restrictions live in prose. Defence only. Members of that mutual. First home buyers. Not for a self-managed super fund. This site reads them out of the text the lender publishes, and keeps the sentence that said so.

That sentence is the point. Every tag can be checked against the lender's own wording instead of taken on trust.

curl https://rategap.com.au/v1/conditions   -H "Authorization: Bearer $RATEGAP_KEY"

{
  "asOf": "2026-09-09T19:30:00.000Z",
  "licence": "Licensed to the subscriber ...",
  "vocabulary": {
    "defence": "defence force only",
    "membership": "members of that mutual or credit union only",
    ...
  },
  "counts": {
    "products": 1929,
    "restricted": 902,
    "tags": 1180,
    "byCondition": { "membership": 479, "package": 198, ... }
  },
  "products": [
    {
      "lender": "ABC",
      "lenderName": "Example Mutual",
      "productId": "abc-123",
      "product": "Defence Home Loan",
      "conditions": [
        {
          "condition": "defence",
          "source": "regex",
          "evidence": "Available to serving and ex-serving members of the ADF."
        }
      ]
    }
  ]
}

Only restricted products are listed. A product that is not there has no restriction this site found — that is the answer, not a gap. The full product list is in the free CSV.

The access field says which of the two answers you got: full or summary.

Where a tag came from

Told apart rather than blended, so you can weigh them differently. The comparison on this site treats both as restrictions.

The words

The same list the site shows a borrower, from the same code.

A free key sees the shape, not the data

Ask with a free key and you get the counts, the vocabulary and the date — how many products carry each restriction, and what every word means. Enough to decide whether this is worth paying for.

The classifications themselves need the subscription. One call is the whole layer, so a free tier that included them would be the product, given away.

This part is not CC BY

The rates are the lenders'. This is not. It is not in their filings, and it is not republishable as a dataset — it is licensed for use inside what you build.

It changes when the nightly capture changes, which is rarely: product wording moves far more slowly than pricing. Keep the ETag and send it back as If-None-Match. A 304 costs you nothing and does not count as a call.

What you send

Send a value it does not recognise and you get an error naming the field. The borrower's page quietly corrects those instead. A program that sends one has a bug, and answering the wrong question would hide it.

The gapBand field

This is the one most callers want. It says how large the gap is and where it comes from. What to do about it is yours to decide.

The site's own headline is worked out from this same value, by the same code. It is not a second opinion worked out for the API.

When it says no

Every reply carries an x-calls-remaining header. A call only counts when you get an answer. A bad request costs you nothing, and neither does a 304.

The 429 is the only one that lifts by itself. It says when, in Retry-After and in a reset field: midnight UTC on the first, because the count is a calendar month and so is the invoice.

What it will not do

It will not tell anyone what to do with their money. It reports what lenders advertise, and what the arithmetic says about it. It does not assess whether any loan suits anyone, and it is not credit assistance or advice.

It also keeps nothing. The loan figures you send are used to answer the call, then dropped. That is the same promise the privacy page makes for the site. All I record is which key called, and when.

One more party sees the request: Cloudflare sits in front of this and keeps short-lived logs of the requests themselves, headers and all. Three days, or seven. Nothing here can opt a single header out of that, and it is worth knowing before you put a key in one.

Terms

• You are responsible for any licence or authorisation your use of this needs, including under credit and financial services law. This site holds none and does not supply any.
• Do not present the output to your own customers as this site's recommendation, or as advice about their loan. It describes advertised rates.
• The figures are rates lenders advertise, read on the date shown. They can be out of date, and a lender can decline to offer one. Check with the lender before relying on a figure.
• The rates themselves are free under CC BY 4.0, and you must credit RateGap. The derived figures and eligibility readings are this site's own work, and are licensed for use inside what you build. Do not resell them as a competing data service.
• A key can be withdrawn for misuse, such as sharing it or going round the monthly limit.