Share a Simulator draft link

A draft link opens the Tenderly Simulator with the form prefilled: a single call or a multi-call bundle, including state overrides, funded balances, and edited contract source. Nothing runs until the recipient clicks Simulate, so the link is safe to share in test reports, pull requests, governance proposals, or alerts. A draft is stored server-side and referenced by id. The link itself carries no payload and no project: https://dashboard.tenderly.co/simulator/new?draftId=<id>

Build the simulation in the Simulator: pick the network, add one or more calls, set overrides, apply source edits.
Click Share draft in the page header. The draft is saved and the link is copied to your clipboard.

The link works for bundles and edited sources, and has no length limit. A draft shared from the dashboard is readable by members of the project it was saved in, and expires automatically.

Simulator header with the Share draft button next to Simulate, and the tooltip explaining that the link works for bundles and edited sources — Share draft in the Simulator header saves the current setup and copies a link that reopens it.

What happens when a draft link opens

The dashboard makes one request for the draft and then, depending on the response:

Member of the draft’s project. The dashboard redirects into that project’s Simulator with the form prefilled and no prompts.
Shared draft (created through the API with shared: true). A Select Project dialog opens first; the draft opens in the project the recipient picks.
Invalid id, expired draft, or no access. All three produce the same response so draft IDs cannot be probed. The recipient sees “This draft link is invalid, has expired, or you don’t have access to it.” and lands on the dashboard home.
Logged out. The recipient signs in first, then the flow continues with the same link.
Unsaved edits in the Simulator. Opening a draft replaces the current form, so the dashboard asks for confirmation before discarding the edits.

Select Project dialog shown when opening a shared draft link, with a project dropdown — A shared draft is not tied to a project, so the recipient picks where to open it.

Partial restore

Each call in a draft is restored independently, so one problematic call does not reject the whole draft. A dismissible banner lists what did not survive, per call:

Case	Result
The contract could not be loaded	The address is kept. Re-select the contract to retry.
The saved function is no longer on the contract ABI	The function select is emptied. Pick the function again.
The call carried an imported ABI	The ABI text is kept but not re-applied. Open Edit ABI and import it again.
The edited source failed to compile	The source stays on the call; the ABI falls back to the verified contract. Open Edit source and re-apply to retry.
A funded ERC-20 token’s balance slot could not be resolved	The token stays on the form. Re-select it in Fund address to retry.

No banner means everything was restored. A malformed payload, or a network that is not enabled on the project, rejects the draft wholesale: the recipient sees an error and an empty form.

Simulator with a prefilled 3-call bundle and a warning banner listing the calls whose contract or function could not be restored — The restore banner names the calls that need attention after a draft opens.

Create a draft link from CI or tooling

Create the draft with the drafts API, then put the returned id in the link. Requests authenticate with an access key; the caller must be a member of the project in the URL. POST https://api.tenderly.co/api/v2/account/{account}/project/{project}/simulation-drafts (API reference)

Body field	Type	Required	Description
`payload`	object	yes	The draft payload. Stored as-is; the API does not validate its structure. A malformed payload is rejected when the link opens, not when the draft is created.
`shared`	boolean	no	`false` (default) scopes the draft to the project in the URL: only its members can open it, and they are redirected straight into it. `true` makes the draft openable by any signed-in Tenderly user, in a project of their choice. Use it for links aimed outside your organization, for example a governance UI that prefills a proposal simulation.

The response is { "resource_id": "<uuid>" }.

curl -X POST "https://api.tenderly.co/api/v2/account/$ACCOUNT/project/$PROJECT/simulation-drafts" \
  -H "X-Access-Key: $TENDERLY_ACCESS_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "payload": {
      "v": 2,
      "network": { "id": "1" },
      "rows": [
        {
          "contractAddress": "0xdac17f958d2ee523a2206206994597c13d831ec7",
          "from": "0xab5801a7d398351b8be11c439e05c5b3259aec9b",
          "inputDataType": "raw",
          "rawFunctionInput": "0xa9059cbb…"
        }
      ]
    }
  }'
# {"resource_id":"3f2a6c1e-…"}

import os, requests

payload = {
    "v": 2,
    "network": {"id": "1"},
    "rows": [
        {
            "contractAddress": "0xdac17f958d2ee523a2206206994597c13d831ec7",
            "from": "0xab5801a7d398351b8be11c439e05c5b3259aec9b",
            "inputDataType": "raw",
            "rawFunctionInput": "0xa9059cbb…",
        }
    ],
}

response = requests.post(
    f"https://api.tenderly.co/api/v2/account/{os.environ['ACCOUNT']}/project/{os.environ['PROJECT']}/simulation-drafts",
    headers={"X-Access-Key": os.environ["TENDERLY_ACCESS_KEY"]},
    json={"payload": payload},
)
response.raise_for_status()

url = f"https://dashboard.tenderly.co/simulator/new?draftId={response.json()['resource_id']}"

// Node.js 18+
const payload = {
  v: 2,
  network: { id: "1" },
  rows: [
    {
      contractAddress: "0xdac17f958d2ee523a2206206994597c13d831ec7",
      from: "0xab5801a7d398351b8be11c439e05c5b3259aec9b",
      inputDataType: "raw",
      rawFunctionInput: "0xa9059cbb…",
    },
  ],
};

const response = await fetch(
  `https://api.tenderly.co/api/v2/account/${process.env.ACCOUNT}/project/${process.env.PROJECT}/simulation-drafts`,
  {
    method: "POST",
    headers: {
      "X-Access-Key": process.env.TENDERLY_ACCESS_KEY,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ payload }),
  },
);

const { resource_id } = await response.json();
const url = `https://dashboard.tenderly.co/simulator/new?draftId=${resource_id}`;

Read a draft back

GET https://api.tenderly.co/api/v2/account/{account}/project/{project}/simulation-drafts/{id} (API reference) The project in the URL is the caller’s own project (any project they can view). The draft’s visibility determines access:

A project-scoped draft returns { "payload": {…}, "account_id": "…", "project_id": "…" } when the caller can view the draft’s origin project.
A shared draft returns { "payload": {…} } with no origin information.
Anything else (unknown id, expired draft, no access to the origin project) returns 404 with "slug": "resource_not_found".

The fastest way to get a correct payload for an advanced setup is to build it in the Simulator, click Share draft, and GET the draft by the id in the copied link. The response is a payload the dashboard accepts, including the stateOverrides, customSource, and fundAddress shapes.

Draft payload

Field	Type	Required	Description
`v`	number	yes	Schema version. Must be `2`.
`network`	`{ "id": string }` or `null`	yes	Chain id as a string (`"1"` is Mainnet, `"56"` is BNB Chain, and so on). Must be a network enabled on the project where the draft opens, otherwise the recipient gets a “network not available” error and an empty form. Always set it. `null` is accepted but skips the contract lookup and leaves the form mostly unusable. See Supported Networks for chain ids.
`rows`	array	yes	One object per call, in execution order. At least one row is required. See Row fields. Session-level settings (block selection, `from`, L2 parameters) are taken from the first row.

Row fields

Only contractAddress is required. Omit anything you do not need. Omitted fields keep the form’s defaults, and unknown extra fields are ignored.

Contract and function

Field	Type	Description
`contractAddress`	string	Required. The “to” address. The contract and its ABI are fetched on the recipient’s side when the link opens.
`inputDataType`	`"decoded"` or `"raw"`	Selects the function-input mode. Use `"raw"` with `rawFunctionInput`, or `"decoded"` with `contractFunction` and `functionInputs`.
`rawFunctionInput`	string	Hex calldata (`0x…`) for raw mode. No ABI needed, which makes it the most reliable option for scripts.
`contractFunction`	object or `null`	Decoded-mode function reference: `{ "name": string, "selector"?: string, "signature"?: string }`. `name` is required inside the object. `selector` (4-byte hex, e.g. `"0xa9059cbb"`) is optional but preferred: it is matched exactly, which is safe for overloaded functions. Without it, matching falls back to `name` and may pick the wrong overload. `signature` is informational only.
`functionInputs`	array or object	Decoded-mode argument values. Preferred: a positional array in ABI order, for example `["0xabc…", "1000000", ["0xa…", "0xb…"]]`. Values are strings, numbers, or booleans. Array and tuple arguments may be passed natively as nested arrays or objects, with no pre-stringifying needed. The keyed form `{ "input_0": … }` is also accepted (it is what the dashboard emits).
`contractAbiImport`	string	Pre-fills the in-app Edit ABI field. It is not re-applied when the draft opens: function matching uses the fetched ABI (or the compiled edited source), so this field does not make decoded mode work for unverified contracts. Use raw calldata for those.

Transaction parameters

Field	Type	Description
`from`	string	Sender address.
`gas`	string or number	Gas limit, e.g. `"8000000"`. `0x`-prefixed hex quantities are converted to decimal.
`gasPrice`	string or number	Gas price in wei.
`value`	string or number	Native-token value in wei.

Block selection

Field	Type	Description
`block`	string or number	Block number to simulate at. Omit for the chain head.
`blockIndex`	string, number, or `null`	Transaction position inside the block. `null` or omitted means the start of the block.
`endOfBlock`	boolean	`true` runs the simulated transaction after every transaction in the block (overrides `blockIndex`).
`usePendingBlock`	boolean	`true` simulates on the pending block instead of a fixed number.

See Simulation Parameters for how block selection and transaction index behave in the UI.

L2 parameters

These fields apply to OP-stack and Boba networks only.

Field	Type	Description
`depositTx`	boolean	Mark as an L2 deposit transaction.
`mint`	string	Deposit mint amount.

Overrides

Field	Type	Description
`blockHeaderOverrides`	object	`{ "number"?: …, "timestamp"?: … }`, each a string, number, or `null`. Overrides the simulated block header.
`stateOverrides`	array	Per-contract state overrides: `{ "id"?: string, "contractAddress": string, "balance": string, "storage"?: [{ "key": string, "value": string }], "code"?: string }`. `id` is optional and generated when absent. `balance` is in wei (`""` means no balance override). `storage` keys and values are 32-byte hex.
`accessList`	array	EIP-2930 access list: `{ "address": string, "storageKeys": string[] }`.

Funded balances and edited source

Field	Type	Description
`fundAddress`	object or `null`	The Fund address cheatcode: `{ "targetAddress": string, "tokens": [{ "tokenAddress": string, "amount": string }] }`. Use the zero address `0x0000000000000000000000000000000000000000` as `tokenAddress` to fund the native balance. For ERC-20 tokens the balance storage slot is resolved when the draft opens; if it cannot be resolved, the token stays on the form and the restore banner asks the recipient to re-select it.
`customSource`	object or `null`	An applied source edit: `{ "compilerInfo": {…}, "customSourceData": [{ "name": string, "source": string, "path": string, "contractName"?: string, "address"?: string }] }`. `compilerInfo` is passed to the compiler as-is (compiler version, optimization settings, import remappings); take its shape from a draft shared from the dashboard. The source is compiled when the draft opens and its ABI takes over function matching for that call.
`contractSourceEdited`	boolean	Marks the call’s source as edited. Defaults to `true` when `customSource` is present.

Validation and errors

Creating a draft:

Response	Meaning
`400` `"Draft payload is required"`	`payload` is missing or `null`.
`400` `"Draft payload exceeds the 256KB limit"`	The serialized `payload` is larger than 256 KB.
`401`	Missing or invalid access key.
`404`	The caller is not a member of the project in the URL.

Opening a draft is all-or-nothing at the payload level: a wrong v, a missing rows entry, a non-string contractAddress, or any wrong-typed row field rejects the whole draft with “This draft link is invalid or corrupted”. Per-call problems that depend on live data (contract fetch, function match, source compile, token slot) degrade individually as described in Partial restore.

Limits

Payloads are capped at 256 KB per draft, enforced by the API.
Drafts expire automatically. An expired draft returns 404 from the API and the “invalid, has expired, or you don’t have access” message in the dashboard.
Opening a draft link requires a Tenderly account. Shared drafts (shared: true) are readable by any signed-in user; project-scoped drafts only by members of the origin project.
The contract ABI is fetched when the link opens. If it cannot be resolved (an unverified contract), decoded-mode calls open with the address filled but no function selected. Raw mode is immune to this.

Legacy `?draft=` links

Before server-side drafts, the dashboard encoded a single call directly into the URL: https://dashboard.tenderly.co/<org>/<project>/simulator/new?draft=<value> <value> is a version-1 payload ({ "v": 1, "network": {…}, "row": {…} }, one row instead of rows) as UTF-8 JSON, then base64url (+ to -, / to _, = padding stripped). Existing links keep opening. The row object accepts the row fields above except fundAddress, customSource, and contractSourceEdited, and the whole URL must stay under about 2000 characters. The dashboard no longer produces this format; use the drafts API for new integrations. For the form fields a draft populates, see Simulation Parameters. To keep a modified state as a persistent environment instead of a one-shot simulation, use Virtual Environments.

Getting Started

Simulator

Console

Monitor

Node RPC

AI Tools

Account & Settings

Share a Simulator draft link

What happens when a draft link opens

Partial restore

Create a draft link from CI or tooling

Read a draft back

Draft payload

Row fields

Contract and function

Transaction parameters

Block selection

L2 parameters

Overrides

Funded balances and edited source

Validation and errors

Limits

Legacy `?draft=` links

​Share a draft from the dashboard

​What happens when a draft link opens

​Partial restore

​Create a draft link from CI or tooling

​Read a draft back

​Draft payload

​Row fields

​Contract and function

​Transaction parameters

​Block selection

​L2 parameters

​Overrides

​Funded balances and edited source

​Validation and errors

​Limits

​Legacy ?draft= links

Share a draft from the dashboard

What happens when a draft link opens

Partial restore

Create a draft link from CI or tooling

Read a draft back

Draft payload

Row fields

Contract and function

Transaction parameters

Block selection

L2 parameters

Overrides

Funded balances and edited source

Validation and errors

Limits

Legacy `?draft=` links