--- title: "Create a simulation draft" method: POST path: "/v2/account/{accountSlug}/project/{projectSlug}/simulation-drafts" tags: ["Simulator"] --- # Create a simulation draft `POST /v2/account/{accountSlug}/project/{projectSlug}/simulation-drafts` Store a Simulator setup (one call or a multi-call bundle, including state overrides, funded balances, and edited contract source) as a draft and receive an ID for a shareable link. Opening the link only prefills the Simulator form; nothing runs until the recipient clicks **Simulate**. Put the returned `resource_id` in a dashboard link: `https://dashboard.tenderly.co/simulator/new?draftId={resource_id}` **Visibility** - `shared: false` (default): the draft is scoped to the project in the URL. Only members of that project can open it, and the dashboard redirects them straight into the project's Simulator. - `shared: true`: any signed-in Tenderly user can open the draft in a project of their choice (the dashboard shows a project picker first). Use it for links aimed outside your organization, for example a governance UI that prefills a proposal simulation. **Payload handling** The `payload` is stored as received. The API enforces only the 256 KB size limit; the payload structure is validated when the draft opens in the dashboard, and a malformed payload is rejected there with an empty form. The dashboard itself creates drafts through this endpoint with `shared: false`. Drafts expire automatically. Learn more about [Simulator draft links](https://docs.tenderly.co/simulator-ui/draft-links). ## Path parameters - `accountSlug` string, required - `projectSlug` string, required ## Request body - SimulationDraftCreateRequest — Request body for creating a simulation draft. - `payload` SimulationDraftPayload, required — A Simulator form snapshot. The API stores it as received; the dashboard validates it when the draft opens. A wrong `v`, an empty `rows` array, a non-string `contractAddress`, or a wrong-typed row field rejects the whole draft on open. - `v` 2, required — Payload schema version. Must be `2`. - `network` object, nullable, required — Network the draft targets, identified by chain ID as a string. Must be a network enabled on the project where the draft opens, otherwise the dashboard reports the network as unavailable and shows an empty form. `null` is accepted but skips the contract lookup and leaves the form mostly unusable. - `id` string, required — Chain ID as a string, for example `"1"` for Mainnet. - `rows` SimulationDraftRow[], required — One entry per call, in execution order. At least one row is required. Session-level settings (block selection, `from`, L2 parameters) are taken from the first row. - `contractAddress` string, required — The "to" address. The contract and its ABI are fetched when the draft opens. - `inputDataType` 'decoded' | 'raw' — Function-input mode. Use `raw` with `rawFunctionInput`, or `decoded` with `contractFunction` and `functionInputs`. - `rawFunctionInput` string — Hex calldata for raw mode. No ABI is needed, which makes it the most reliable option for scripts. - `contractFunction` object, nullable — Decoded-mode function reference. `selector` (4-byte hex) is matched exactly and is safe for overloaded functions; without it, matching falls back to `name` and may pick the wrong overload. `signature` is informational only. - `name` string, required - `selector` string — 4-byte function selector. - `signature` string - `functionInputs` union — Decoded-mode argument values. Preferred: a positional array in ABI order. Array and tuple arguments may be passed natively as nested arrays or objects. The keyed form `{ "input_0": ... }` is also accepted (it is what the dashboard emits). - unknown[] - unknown - object - `contractAbiImport` string — Prefills the in-app **Edit ABI** field. Not re-applied when the draft opens: function matching uses the fetched ABI (or the compiled edited source). - `from` string — Sender address. - `gas` union — Gas limit. `0x`-prefixed hex quantities are converted to decimal. - string - number - `gasPrice` union — Gas price in wei. - string - number - `value` union — Native-token value in wei. - string - number - `block` union — Block number to simulate at. Omit for the chain head. - string - number - `blockIndex` union — Transaction position inside the block. `null` or omitted means the start of the block. - string - number - `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. - `depositTx` boolean — Mark as an L2 deposit transaction (OP-stack and Boba networks only). - `mint` string — Deposit mint amount (OP-stack and Boba networks only). - `blockHeaderOverrides` object — Overrides for the simulated block header. - `number` union - string - number - `timestamp` union - string - number - `stateOverrides` object[] — Per-contract state overrides applied before the call runs. - `id` string — UI row key. Optional; generated when absent. - `contractAddress` string, required - `balance` string, required — Balance override in wei. An empty string means no balance override. - `storage` object[] - `key` string, required — 32-byte hex storage slot. - `value` string, required — 32-byte hex value. - `code` string — Bytecode override. - `accessList` object[] — EIP-2930 access list. - `address` string, required - `storageKeys` string[], required - `fundAddress` object, nullable — The **Fund address** cheatcode. Use the zero address as `tokenAddress` to fund the native balance. For ERC-20 tokens the balance storage slot is resolved when the draft opens. - `targetAddress` string, required - `tokens` object[], required - `tokenAddress` string, required - `amount` string, required — Amount in the token's smallest unit, as a string. - `customSource` object, nullable — An applied source edit. `compilerInfo` is passed to the compiler as-is (compiler version, optimization settings, import remappings); take its shape from a draft created in the dashboard. The source is compiled when the draft opens and its ABI takes over function matching for this call. - `compilerInfo` object, required - `customSourceData` object[], required - `name` string, required - `source` string, required - `path` string, required - `contractName` string - `address` string - `contractSourceEdited` boolean — Marks the call's source as edited. Defaults to `true` when `customSource` is present. - `shared` boolean — `false` (default) scopes the draft to the project in the URL: only its members can open it. `true` makes the draft openable by any signed-in Tenderly user in a project of their choice. ## Response `200` The draft was stored. - SimulationDraftCreateResponse - `resource_id` string, uuid, required — ID of the stored draft. Use it as the `draftId` query parameter of the dashboard link: `https://dashboard.tenderly.co/simulator/new?draftId={resource_id}`. ## Other responses - `400` — Bad Request - `401` — Unauthorized - `403` — Forbidden - `404` — The resource was not found. - `429` — The request was rate limited. See the [rate limits](#section/Introduction/Rate-limits) section for the current limits and how request counts expire. - `500` — Server error. ## Changes - **2026-08-28** `e512753e74ce` — 1 info - endpoint added [Change history](https://skmtc.dev/tenderly/apis/tenderly-api/changes/v2/account/:accountSlug/project/:projectSlug/simulation-drafts/post.md) --- [API](https://skmtc.dev/tenderly/apis/tenderly-api.md) · [All operations](https://skmtc.dev/tenderly/apis/tenderly-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/tenderly/tenderly-api/revisions/e512753e74ce/schema)