> For the complete documentation index, see [llms.txt](https://docs.tronsave.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tronsave.io/developers/legacy-api-v0/signed-tx.md). # Buy — Signed Transaction {% hint style="warning" %} **Legacy API.** This page documents the v0 signed-transaction flow under the `/v0/` base path. New integrations should use the current API. See [Buy with Signed Transaction (v2)](/developers/api-reference/buy-resources/signed-tx.md). {% endhint %} The signed-transaction flow lets you buy Energy by paying TRX directly from your own wallet — no API key required, since the TRX transfer is signed with your private key. There are three steps: 1. [Estimate TRX](#step-1-estimate-trx) — calculate the TRX needed for the desired amount and rental duration. 2. [Get a signed transaction](#step-2-get-a-signed-transaction) — sign a TRX transfer to the TronSave fund address, either yourself or via the API. 3. [Create an order](#step-3-create-an-order) — submit the signed transaction to place the buy order. {% hint style="info" %} **Before you start:** make sure you have the wallet's private key and that the wallet holds enough TRX to cover the estimated cost. {% endhint %} The mainnet base URL is `https://api.tronsave.io`. For testing on the TRON Nile testnet, use `https://api-dev.tronsave.io`. See [Environments](/developers/environments.md). | Step | Method | Mainnet | Testnet (Nile) | | ---------------------- | ------ | ----------------------------------------- | --------------------------------------------- | | Estimate TRX | `POST` | `https://api.tronsave.io/v0/estimate-trx` | `https://api-dev.tronsave.io/v0/estimate-trx` | | Get Signed Transaction | `POST` | `https://api.tronsave.io/v0/signed-tx` | `https://api-dev.tronsave.io/v0/signed-tx` | | Create Order | `POST` | `https://api.tronsave.io/v0/buy-energy` | `https://api-dev.tronsave.io/v0/buy-energy` | *** ## Step 1: Estimate TRX Calculate the TRX needed for a given resource amount and rental duration. The response gives you the `unit_price` and the `estimate_trx` you must transfer in Step 2. **`POST`** **`https://api.tronsave.io/v0/estimate-trx`** {% hint style="info" %} **Rate limit:** 15 requests per 1 second. {% endhint %} ### Headers | Header | Value | Required | | -------------- | ------------------ | -------- | | `Content-Type` | `application/json` | Yes | ### Request params
FieldPositionTypeRequiredDescription
amountbodynumbertrueThe number of resources
buy_energy_typebodystring, numbertrue

"FAST", "MEDIUM", "SLOW" or number:


-"FAST": If market ready to fill = 100%, FAST = MEDIUM. If the market ready to fill < 100%, FAST = MEDIUM + 10. If market ready to fill = 0%, FAST = SLOW + 20.

-"MEDIUM": The lowest price for the maximum market fill for this order. If market ready to fill = 0%, MEDIUM = SLOW + 10.

-"SLOW": The lowest price that can be set for this order.

-If the price is a number, the price unit is equal to SUN

duration_millisecbodynumbertrueThe duration of the bought resource, time unit is equal to millisecond.
request_addressbodystringfalseThe address of requester.
target_addressbodystringfalseThe address of receiver resource.
is_partialbodybooleanfalseAllow the order to be filled partially or not.
### Request body example ```json { "amount": 100000, "buy_energy_type": "MEDIUM", "duration_millisec": 259200000 } ``` ### Responses
FieldTypeRequiredDescription
unit_pricenumbertrueprice in SUN of energy that fit with your buy_energy_type
duration_millisecnumbertrue
available_energynumbertruetotal amount available energy on TronSave market that match with unit_price
estimate_trxnumbertrueestimate total trx value will pay for buy all available_energy with price is unit_price in duration_millisec
#### Success ```json { "unit_price": 45, "duration_millisec": 259200000, "available_energy": 4298470, "estimate_trx": 13500000 } ``` The `estimate_trx` value is returned in SUN (1 TRX = 1,000,000 SUN). #### Error This endpoint does not require an `apikey` header — the signed-transaction flow authenticates through the wallet-signed TRX transfer, so no authentication error applies here. A request with a missing or invalid field returns a `400 Bad Request` whose `message` names the offending field: ```json { "statusCode": 400, "code": "FST_ERR_VALIDATION", "error": "Bad Request", "message": "body must have required property 'amount'" } ``` *** ## Step 2: Get a signed transaction You need a signed TRX transfer of `estimate_trx` SUN from the buyer's address to the TronSave fund address. You can build it yourself, or let the API do it. ### TronSave fund address {% tabs %} {% tab title="MAINNET" %} ``` TWZEhq5JuUVvGtutNgnRBATbF8BnHGyn4S ``` {% endtab %} {% tab title="Nile (for testing)" %} {% hint style="warning" %} This fund address is for testing purposes only on the TRON Nile network. {% endhint %} ``` TATT1UzHRikft98bRFqApFTsaSw73ycfoS ``` {% endtab %} {% endtabs %} ### Option 1: Write your own function Using `tronWeb`, build a `sendTrx` transfer for `estimate_trx` (from Step 1) and sign it with the buyer's private key: ```javascript const dataSendTrx = await tronWeb.transactionBuilder.sendTrx('TRONSAVE_FUND_ADDRESS', estimate_trx, 'BUYER_ADDRESS') const signed_tx = await tronWeb.trx.sign(dataSendTrx, 'PRIVATE_KEY'); ``` {% hint style="info" %} * `BUYER_ADDRESS` is the buyer's public address. * `PRIVATE_KEY` is the buyer's private key. * `TRONSAVE_FUND_ADDRESS` is the TronSave fund address shown above. {% endhint %} ### Option 2: Use the Get Signed Transaction API **`POST`** **`https://api.tronsave.io/v0/signed-tx`** {% hint style="info" %} **Rate limit:** 15 requests per 1 second. {% endhint %} #### Headers | Header | Value | Required | | -------------- | ------------------ | -------- | | `Content-Type` | `application/json` | Yes | #### Request params
FieldPositionTypeRequiredDescription
addressbodystringtrueThe buyer's public address
private_keybodystringtrueThe buyer's private key
estimate_trxbodynumbertrueThe amount of TRX to be paid is calculated in SUN. (estimate_trx from Step 1)
#### Request body example ```json { "address": "TM6ZeEgpefyGWeMLuzSbfqTGkPv8Z65432", "private_key": "{{yourprivateKey}}", "estimate_trx": 13500000 } ``` #### Responses **Success** ```json { "visible": false, "txID": "446eed36e31249b98b201db2e81a3825b185f1a3d8b2fea348b24fc021e58e0d", "raw_data": { "contract": [ { "parameter": { "value": { "amount": 13500000, "owner_address": "417a0d868d1418c9038584af1252f85d486502eec0", "to_address": "41055756f33f419278d9ea059bd2b21120e6add748" }, "type_url": "type.googleapis.com/protocol.TransferContract" }, "type": "TransferContract" } ], "ref_block_bytes": "0713", "ref_block_hash": "6c5f7686f4176139", "expiration": 1691465106000, "timestamp": 1691465046758 }, "raw_data_hex": "0a02071322086c5f7686f417613940d084b5999d315a68080112640a2d747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e5472616e73666572436f6e747261637412330a15417a0d868d1418c9038584af1252f85d486502eec0121541055756f33f419278d9ea059bd2b21120e6add74818e0fcb70670e6b5b1999d31", "signature": ["xxxxxxxxx"] } ``` **Error** No `apikey` header is required for this endpoint. A request with a missing or invalid field returns a `400 Bad Request` whose `message` names the offending field: ```json { "statusCode": 400, "code": "FST_ERR_VALIDATION", "error": "Bad Request", "message": "body must have required property 'estimate_trx'" } ``` *** ## Step 3: Create an order Submit the signed transaction (from Step 2) together with the order parameters to place the Energy purchase. **`POST`** **`https://api.tronsave.io/v0/buy-energy`** {% hint style="info" %} **Rate limit:** 15 requests per 1 second. {% endhint %} ### Headers | Header | Value | Required | | -------------- | ------------------ | -------- | | `Content-Type` | `application/json` | Yes | {% hint style="info" %} This endpoint authenticates through the `signed_tx` you submit — the TRX payment is signed by your own wallet — so an `apikey` header is not required. {% endhint %} ### Request params
FieldTypeRequiredDescription
resource_typestringtrue"ENERGY"
unit_pricenumbertruePrice unit is equal to SUN.
allow_partial_fillbooleantrueAllow the order to be filled partially or not
target_addressstringtrueResource receiving address
duration_millisecnumbertrueThe duration of the bought resource, time unit is equal to millisec.
tx_idstringtrueTransaction ID
signed_txSignedTransactiontrueSigned transaction, note that it is a JSON object (the signed_tx from Step 2)
only_create_when_fulfilledBooleanfalse

[true] => order only create when it can be fulfilled

[false] => order will create even it can not be fulfilled

Default value: false

max_price_acceptedNumberfalseOnly create order when the estimate price less than this value.
add_order_incompleteBooleanfalse

[true] => order only create when there has no same parameters order is not complete in order list

[false] => order will create even there has no same parameters order is not complete in order list

Default value: false

### Request body example ```json { "resource_type": "ENERGY", "unit_price": 45, "allow_partial_fill": true, "target_address": "TM6ZeEgpefyGWeMLuzSbfqTGkPv8Z6Jm4X", "duration_millisec": 259200000, "tx_id": "446eed36e31249b98b201db2e81a3825b185f1a3d8b2fea348b24fc021e58e0d", "signed_tx": { "visible": false, "txID": "446eed36e31249b98b201db2e81a3825b185f1a3d8b2fea348b24fc021e58e0d", "raw_data": { "contract": [ { "parameter": { "value": { "amount": 13500000, "owner_address": "417a0d868d1418c9038584af1252f85d486502eec0", "to_address": "41055756f33f419278d9ea059bd2b21120e6add748" }, "type_url": "type.googleapis.com/protocol.TransferContract" }, "type": "TransferContract" } ], "ref_block_bytes": "0713", "ref_block_hash": "6c5f7686f4176139", "expiration": 1691465106000, "timestamp": 1691465046758 }, "raw_data_hex": "0a02071322086c5f7686f417613940d084b5999d315a68080112640a2d747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e5472616e73666572436f6e747261637412330a15417a0d868d1418c9038584af1252f85d486502eec0121541055756f33f419278d9ea059bd2b21120e6add74818e0fcb70670e6b5b1999d31", "signature": ["xxxxxxxxx"] }, "only_create_when_fulfilled": false, "max_price_accepted": 200, "add_order_incomplete": false } ``` ### Responses #### Success ```json { "message": "651d2306e55c073f6ca0992e" } ``` The `message` value is the `order_id` of the created order. #### Error This endpoint authenticates through the submitted `signed_tx`, so no `apikey` header and no authentication error apply. A request with a missing or invalid field returns a `400 Bad Request` whose `message` names the offending field: ```json { "statusCode": 400, "code": "FST_ERR_VALIDATION", "error": "Bad Request", "message": "body must have required property 'signed_tx'" } ``` *** ## Request examples The examples below show the full flow: estimate, sign the TRX transfer to the fund address, then create the order. Replace `YOUR_TRON_ADDRESS`, the private key, and the fund address as needed. Signing the TRX transfer (Step 2, Option 1) typically uses a TRON library; the cURL example uses the API (Step 2, Option 2) instead. {% tabs %} {% tab title="cURL" %} ```bash # Step 1: Estimate TRX curl -X POST https://api.tronsave.io/v0/estimate-trx \ -H "Content-Type: application/json" \ -d '{ "amount": 100000, "buy_energy_type": "MEDIUM", "duration_millisec": 259200000 }' # Step 2: Get a signed transaction (Option 2) curl -X POST https://api.tronsave.io/v0/signed-tx \ -H "Content-Type: application/json" \ -d '{ "address": "YOUR_TRON_ADDRESS", "private_key": "YOUR_PRIVATE_KEY", "estimate_trx": 13500000 }' # Step 3: Create the order (use the signed_tx returned above) curl -X POST https://api.tronsave.io/v0/buy-energy \ -H "Content-Type: application/json" \ -d '{ "resource_type": "ENERGY", "unit_price": 45, "allow_partial_fill": true, "target_address": "YOUR_TRON_ADDRESS", "duration_millisec": 259200000, "tx_id": "446eed36e31249b98b201db2e81a3825b185f1a3d8b2fea348b24fc021e58e0d", "signed_tx": { "visible": false, "txID": "446eed36...", "raw_data": {}, "raw_data_hex": "0a020713...", "signature": ["xxxxxxxxx"] }, "only_create_when_fulfilled": false, "max_price_accepted": 200, "add_order_incomplete": false }' ``` {% endtab %} {% tab title="JavaScript" %} ```javascript // Requires tronweb for signing the TRX transfer. const TRONSAVE_API_URL = "https://api.tronsave.io"; const TRONSAVE_FUND_ADDRESS = "TWZEhq5JuUVvGtutNgnRBATbF8BnHGyn4S"; // Step 1: Estimate TRX const estimateRes = await fetch(`${TRONSAVE_API_URL}/v0/estimate-trx`, { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ amount: 100000, buy_energy_type: "MEDIUM", duration_millisec: 259200000, }), }); const { unit_price, duration_millisec, estimate_trx } = await estimateRes.json(); // Step 2 (Option 1): Sign the TRX transfer to the fund address const dataSendTrx = await tronWeb.transactionBuilder.sendTrx( TRONSAVE_FUND_ADDRESS, estimate_trx, "YOUR_TRON_ADDRESS" ); const signed_tx = await tronWeb.trx.sign(dataSendTrx, "YOUR_PRIVATE_KEY"); // Step 3: Create the order const orderRes = await fetch(`${TRONSAVE_API_URL}/v0/buy-energy`, { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ resource_type: "ENERGY", unit_price, allow_partial_fill: true, target_address: "YOUR_TRON_ADDRESS", duration_millisec, tx_id: signed_tx.txID, signed_tx, only_create_when_fulfilled: false, max_price_accepted: 200, add_order_incomplete: false, }), }); console.log(await orderRes.text()); ``` {% endtab %} {% tab title="Python" %} ```python import requests TRONSAVE_API_URL = "https://api.tronsave.io" # Step 1: Estimate TRX estimate = requests.post( f"{TRONSAVE_API_URL}/v0/estimate-trx", json={ "amount": 100000, "buy_energy_type": "MEDIUM", "duration_millisec": 259200000, }, ).json() unit_price = estimate["unit_price"] duration_millisec = estimate["duration_millisec"] estimate_trx = estimate["estimate_trx"] # Step 2 (Option 2): Get a signed transaction from the API signed_tx = requests.post( f"{TRONSAVE_API_URL}/v0/signed-tx", json={ "address": "YOUR_TRON_ADDRESS", "private_key": "YOUR_PRIVATE_KEY", "estimate_trx": estimate_trx, }, ).json() # Step 3: Create the order order = requests.post( f"{TRONSAVE_API_URL}/v0/buy-energy", json={ "resource_type": "ENERGY", "unit_price": unit_price, "allow_partial_fill": True, "target_address": "YOUR_TRON_ADDRESS", "duration_millisec": duration_millisec, "tx_id": signed_tx["txID"], "signed_tx": signed_tx, "only_create_when_fulfilled": False, "max_price_accepted": 200, "add_order_incomplete": False, }, ).json() print(order) ``` {% endtab %} {% tab title="Java" %} ```java import java.net.URI; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; public class BuyWithSignedTx { static final String TRONSAVE_API_URL = "https://api.tronsave.io"; static String post(HttpClient client, String path, String body) throws Exception { HttpRequest request = HttpRequest.newBuilder() .uri(URI.create(TRONSAVE_API_URL + path)) .header("Content-Type", "application/json") .POST(HttpRequest.BodyPublishers.ofString(body)) .build(); return client.send(request, HttpResponse.BodyHandlers.ofString()).body(); } public static void main(String[] args) throws Exception { HttpClient client = HttpClient.newHttpClient(); // Step 1: Estimate TRX String estimate = post(client, "/v0/estimate-trx", """ { "amount": 100000, "buy_energy_type": "MEDIUM", "duration_millisec": 259200000 } """); System.out.println(estimate); // Step 2 (Option 2): Get a signed transaction from the API String signedTx = post(client, "/v0/signed-tx", """ { "address": "YOUR_TRON_ADDRESS", "private_key": "YOUR_PRIVATE_KEY", "estimate_trx": 13500000 } """); System.out.println(signedTx); // Step 3: Create the order (embed the signedTx JSON from Step 2) String order = post(client, "/v0/buy-energy", """ { "resource_type": "ENERGY", "unit_price": 45, "allow_partial_fill": true, "target_address": "YOUR_TRON_ADDRESS", "duration_millisec": 259200000, "tx_id": "446eed36e31249b98b201db2e81a3825b185f1a3d8b2fea348b24fc021e58e0d", "signed_tx": %s, "only_create_when_fulfilled": false, "max_price_accepted": 200, "add_order_incomplete": false } """.formatted(signedTx)); System.out.println(order); } } ``` {% endtab %} {% tab title="Go" %} ```go package main import ( "bytes" "fmt" "io" "net/http" ) const tronsaveAPIURL = "https://api.tronsave.io" func post(path string, body []byte) string { req, err := http.NewRequest(http.MethodPost, tronsaveAPIURL+path, bytes.NewBuffer(body)) if err != nil { panic(err) } req.Header.Set("Content-Type", "application/json") resp, err := http.DefaultClient.Do(req) if err != nil { panic(err) } defer resp.Body.Close() out, _ := io.ReadAll(resp.Body) return string(out) } func main() { // Step 1: Estimate TRX estimate := post("/v0/estimate-trx", []byte(`{ "amount": 100000, "buy_energy_type": "MEDIUM", "duration_millisec": 259200000 }`)) fmt.Println(estimate) // Step 2 (Option 2): Get a signed transaction from the API signedTx := post("/v0/signed-tx", []byte(`{ "address": "YOUR_TRON_ADDRESS", "private_key": "YOUR_PRIVATE_KEY", "estimate_trx": 13500000 }`)) fmt.Println(signedTx) // Step 3: Create the order (embed the signed_tx JSON from Step 2) order := post("/v0/buy-energy", []byte(`{ "resource_type": "ENERGY", "unit_price": 45, "allow_partial_fill": true, "target_address": "YOUR_TRON_ADDRESS", "duration_millisec": 259200000, "tx_id": "446eed36e31249b98b201db2e81a3825b185f1a3d8b2fea348b24fc021e58e0d", "signed_tx": {}, "only_create_when_fulfilled": false, "max_price_accepted": 200, "add_order_incomplete": false }`)) fmt.Println(order) } ``` {% endtab %} {% tab title="Rust" %} ```rust // Cargo.toml: // reqwest = { version = "0.12", features = ["blocking", "json"] } // serde_json = "1" use reqwest::blocking::Client; use serde_json::{json, Value}; const TRONSAVE_API_URL: &str = "https://api.tronsave.io"; fn post(client: &Client, path: &str, body: &Value) -> Value { client .post(format!("{TRONSAVE_API_URL}{path}")) .header("Content-Type", "application/json") .json(body) .send() .unwrap() .json() .unwrap() } fn main() -> Result<(), Box> { let client = Client::new(); // Step 1: Estimate TRX let estimate = post(&client, "/v0/estimate-trx", &json!({ "amount": 100000, "buy_energy_type": "MEDIUM", "duration_millisec": 259200000 })); println!("{estimate}"); // Step 2 (Option 2): Get a signed transaction from the API let signed_tx = post(&client, "/v0/signed-tx", &json!({ "address": "YOUR_TRON_ADDRESS", "private_key": "YOUR_PRIVATE_KEY", "estimate_trx": estimate["estimate_trx"] })); println!("{signed_tx}"); // Step 3: Create the order let order = post(&client, "/v0/buy-energy", &json!({ "resource_type": "ENERGY", "unit_price": estimate["unit_price"], "allow_partial_fill": true, "target_address": "YOUR_TRON_ADDRESS", "duration_millisec": estimate["duration_millisec"], "tx_id": signed_tx["txID"], "signed_tx": signed_tx, "only_create_when_fulfilled": false, "max_price_accepted": 200, "add_order_incomplete": false })); println!("{order}"); Ok(()) } ``` {% endtab %} {% endtabs %} ## Next steps * Migrate to the current API: [Buy with Signed Transaction (v2)](/developers/api-reference/buy-resources/signed-tx.md). * [Authentication](/developers/authentication.md) and [Environments](/developers/environments.md). * [Glossary](/concepts/glossary.md) for Energy, Bandwidth, TRX, and SUN definitions.