First Sale Flat Stamp Duty API for Tamil Nadu (UDS)

Example

Request

curl -X POST https://verified.realestate/api/v1/tools/first_sale_uds \
  -H "Authorization: Bearer $LANDLENS_KEY" \
  -H "Content-Type: application/json" \
  -d '{"total_consideration":8500000,"guideline_value":7800000}'

Responsereal answer

{
  "ok": true,
  "status": "ok",
  "data": {
    "found": true,
    "chargeable_value": 8500000,
    "chargeable_basis": "stated consideration (higher than the guideline value supplied)",
    "total_consideration": 8500000,
    "total_was_derived": false,
    "composite_route": {
      "instrument": "Single composite sale deed for the flat, at the first sale concession slabs",
      "deed_type": "Apartments",
      "value": 8500000,
      "stamp_duty": 425000,
      "stamp_rule": "5% of value (tiered: 4% below ₹50L, 5% from ₹50L to ₹3Cr, 7% above)",
      "registration_fee": 170000,
      "registration_rule": "2% of value",
      "total": 595000
    },
    "split_route": null,
    "split_route_retired": null,
    "resale_baseline": {
      "instrument": "Ordinary sale deed, the rate a RESALE flat would pay",
      "deed_type": "Conveyance (Sale)",
      "value": 8500000,
      "stamp_duty": 595000,
      "stamp_rule": "7% of value",
      "registration_fee": 170000,
      "registration_rule": "2% of value",
      "total": 765000
    },
    "saving_vs_resale": 170000,
    "saving_route": "Composite deed",
    "value_mismatch": null,
    "rate_source": "First sale slabs from G.O.(Ms) No.131 of 1 Dec 2023 (4% below Rs 50 lakh, 5% from Rs 50 lakh to Rs 3 crore, 7% above, plus 2% registration fee); the resale rate is the Registration Department's published 7% plus 2%."
  },
  "credits_charged": 0
}

A real answer from the API, with the closing note left out for length.

What it returns

One call, one answer. found is false (status not_found) when no price was given.

Field	What it holds
`chargeable_value, chargeable_basis`	The value the duty is worked out on, and why: the price, or the guideline value when that is higher.
`composite_route`	The first sale deed: value, stamp_duty, stamp_rule, registration_fee, registration_rule and total, in rupees.
`resale_baseline`	The same figures at the ordinary sale rate, for comparison.
`saving_vs_resale`	How much less the first sale deed costs than a resale deed of the same value.
`split_route_retired`	When you sent uds_value and construction_value: why the two-document route is no longer priced, and the deduction for a construction agreement registered on or before 30 November 2023.
`value_mismatch`	Set when the stated total does not equal the land share plus construction you sent.
`total_consideration, total_was_derived`	The price used, and whether it was added up from the two parts.
`rate_source, note`	The order the slabs come from, and what the figure leaves out (GST on an under construction unit).

Inputs

The JSON body of the POST is the arguments. Send total_consideration, or uds_value and construction_value and they are added up. Add guideline_value whenever you have it; without it the figure assumes the price is above the guideline.

Argument	Type	What to send
`total_consideration`	number	Total price of the flat in rupees (land share plus construction). If omitted it is taken as uds_value + construction_value.
`uds_value`	number	Value of the undivided share of land in rupees. Added to construction_value to make the composite price when total_consideration is not given.
`construction_value`	number	Cost of construction in rupees. Added to uds_value to make the composite price when total_consideration is not given.
`guideline_value`	number	The official composite value of the whole flat in rupees, if known (composite_value gives the rate per square foot). Used as a floor.
`uds_guideline_value`	number	Guideline value of the land share alone in rupees. Not used since 1 Dec 2023: a first sale is charged on the composite value of the whole flat, so pass the flat's official composite value instead. Accepted so older calls still run.

Code

Set LANDLENS_KEY to your key. In an AI app, connect https://verified.realestate/mcp once and ask in plain words instead. In Postman, download this API's collection, import it (File, Import) and set apiKey.

curl -X POST https://verified.realestate/api/v1/tools/first_sale_uds \
  -H "Authorization: Bearer $LANDLENS_KEY" \
  -H "Content-Type: application/json" \
  -d '{"total_consideration":8500000,"guideline_value":7800000}'

import os, requests

r = requests.post(
    "https://verified.realestate/api/v1/tools/first_sale_uds",
    headers={"Authorization": f"Bearer {os.environ['LANDLENS_KEY']}"},
    json={
        "total_consideration": 8500000,
        "guideline_value": 7800000
    },
    timeout=20,
)
body = r.json()
print(body["status"], body["credits_charged"], body["data"])

const res = await fetch("https://verified.realestate/api/v1/tools/first_sale_uds", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.LANDLENS_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "total_consideration": 8500000,
    "guideline_value": 7800000
  }),
});
const body = await res.json();
console.log(body.status, body.credits_charged, body.data);

I am buying a new flat from the builder in Chennai for 85 lakh. The guideline value works out to 78 lakh. What will stamp duty and registration cost me?

Your AI applies the first sale slabs and tells you the total and how it compares with a resale flat. It is free.

Responses

Every answer has the same envelope. What status can say for this call:

status	What it means
`ok`	The duty was worked out.
`not_found`	No price was given: send total_consideration, or uds_value and construction_value.
`free_limit_reached`	The account has used its free calls for the hour or the day. retry_after says how many seconds to wait; paid calls keep working.

Where the data comes from

Register

The first sale slabs of G.O.(Ms) No.131 of 1 December 2023 and IGR circular 45438/L1/2023 of 14 December 2023, and the Registration Department's published 7% stamp duty and 2% registration fee for an ordinary sale.

Coverage

Apartments, flats, villas and row houses bought first hand from the builder or developer anywhere in Tamil Nadu. A resale flat, a plot and bare land pay the ordinary rate; use stamp_duty for those.

How current

The slabs in force since 1 December 2023. The answer names the order it applies in rate_source.

How we read it

Duty is charged on the higher of the price and the guideline value you supply. The whole value is charged at the slab it falls in (an 85 lakh flat pays 5% on 85 lakh). The old two-document route (a land share sale deed plus a construction agreement) is not priced, because the department now charges every first sale document on the composite value; the answer says so when you send the two parts.

Who uses it

Builders and their sales teams

Quote the registration cost on every unit's cost sheet from the same slabs the sub registrar applies.

Home loan teams

Add the buyer's registration outlay to the loan file without a manual table.

Property portals

Show "all-in price including registration" on new project listings.

Limits and good practice

First sale residential units only. A resale flat, a plot, a commercial unit and every other deed go to stamp_duty.
Without guideline_value the figure is on the price alone. The sub registrar charges on the higher of the two and fixes the final demand.
GST on an under construction unit is not included.
A construction agreement registered on or before 30 November 2023 earns a deduction under G.O.(Ms) No.166 of 19 December 2025. The answer names it but does not compute it.

Pricing

Free

The first sale calculation costs nothing. Free calls have their own allowance per hour and per day, counted across every key and connected app on the account, and it is larger once the account has bought credits. Credits come from the same LandLens wallet as the chat and the minis. How billing works.

Calling at volume?

Free calls have an hourly and daily allowance. For more than that, or a platform built on these registers, we set up limits and a plan to match.

WhatsApp 99961 29996

Questions

Is there an API for stamp duty on a new flat in Tamil Nadu?

Yes, this one. It applies the first sale slabs to the composite value of the flat and returns stamp duty, registration fee and the total.

Can I still pay stamp duty only on the UDS?

No. Since 1 December 2023 the Registration Department charges a first sale flat on its composite value, land share and building together. The API explains this in split_route_retired when you send the two parts.

What are the first sale slabs?

Stamp duty of 4% below Rs 50 lakh, 5% from Rs 50 lakh to Rs 3 crore, and 7% above, plus a 2% registration fee, on the whole value.

Is GST included?

No. GST on an under construction flat is a separate charge on the builder's invoice and is not part of this figure.

What about a resale flat?

A resale flat pays the ordinary 7% stamp duty and 2% registration fee. Use stamp_duty, or read resale_baseline here.