# Adjust a Flex trove's user-set interest rate

Endpoint reference for the 1delta API. Index: https://docs.1delta.io/llms.txt · every endpoint: https://docs.1delta.io/llms-full.txt

---

### POST /v1/actions/flex/set-rate

- operationId: `flex-set-rate`
- docs: https://docs.1delta.io/1delta-api/flex-set-rate/
- markdown: https://docs.1delta.io/1delta-api/flex-set-rate.md
- tags: Actions › Liquity

Adjust a Flex trove's user-set interest rate

Change a Flex trove's user-set annual rate (`adjust_interest_rate`). Flex is the same user-set-rate model as the Liquity family — redemptions take the lowest rates first, so raising the rate moves the trove back in the queue — but it LENDS USDC / WETH from a Yearn Lender instead of minting a stable. A change inside `interest_rate_adj_cooldown` pays the upfront fee again; `maxUpfrontFee` is quoted on chain (5 % headroom) when absent. `interestRate` is a WAD fraction, like the Liquity routes; the applied rate comes back as `interestRate` (and the old one as `previousInterestRate`). EOA-direct: the owner, or an operator it approved, sends it. Rates to pick from: `GET /v1/data/lending/book?marketUid=FLEX_<chainId>_<TROVE_MANAGER>:<chainId>:<borrowToken>` (`pricing: "queue"`).

**Request body** (`application/json`)

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `chainId` | string | yes | EVM chain id, as a decimal string. See the `ChainId` schema. |
| `lender` | string | yes | Per-market key FLEX_<chainId>_<TROVE_MANAGER> |
| `account` | string | yes | Trove owner (tx sender) |
| `troveId` | string | no | Optional when the account holds exactly one trove on the market |
| `interestRate` | string | yes | New annual rate, WAD fraction (5e16 = 5 %), within the market range |
| `maxUpfrontFee` | string | no | Optional fee-guard override, borrow-token raw units |

**Example request body**

```json
{
  "chainId": "1",
  "lender": "FLEX_1_8EE72C388AA73096338EE18CD46A39D98B8983C9",
  "account": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
  "troveId": "string",
  "interestRate": "string",
  "maxUpfrontFee": "string"
}
```

**Response `200`** — Rate-adjust transaction

| Field | Type | Description |
| --- | --- | --- |
| `success` | true |  |
| `data` | object | Informational data (quotes, simulation results, etc.) |
| `actions` | object | Transaction calldata and approvals. Null for quote-only responses (no account provided). |
| `actions.transactions` | object[] | Pre-trade setup transactions (e.g. e-mode switch, collateral enable). Execute these before the main swap. Empty when no setup is needed. |
| `actions.transactions[].chainType` | "evm" | Which VM executes this step. ABSENT means `evm`, which is the only value any endpoint returns today — every EVM response is unchanged. A non-EVM chain would return a different shape (a serialized, PERISHABLE transaction rather than `to`/`data`/`value`) carrying its own `chainType`, so a client that wants to stay forward-compatible should branch on this field rather than assume `to` is present. |
| `actions.transactions[].to` | string | Target contract address |
| `actions.transactions[].data` | string | Encoded calldata |
| `actions.transactions[].value` | string | ETH value to send with the transaction |
| `actions.transactions[].description` | string | Human-readable label. For `alternatives`, this is the aggregator name (e.g. "Paraswap"). For `transactions`, describes the setup action (e.g. "Switch e-mode to 1"). |
| `actions.alternatives` | object[] | DEX aggregator swap transactions sorted by best output (descending). Each entry's `description` is the aggregator name. The client should pick one to execute. Present on loop action endpoints. |
| `actions.alternatives[].chainType` | "evm" | Which VM executes this step. ABSENT means `evm`, which is the only value any endpoint returns today — every EVM response is unchanged. A non-EVM chain would return a different shape (a serialized, PERISHABLE transaction rather than `to`/`data`/`value`) carrying its own `chainType`, so a client that wants to stay forward-compatible should branch on this field rather than assume `to` is present. |
| `actions.alternatives[].to` | string | Target contract address |
| `actions.alternatives[].data` | string | Encoded calldata |
| `actions.alternatives[].value` | string | ETH value to send with the transaction |
| `actions.alternatives[].description` | string | Human-readable label. For `alternatives`, this is the aggregator name (e.g. "Paraswap"). For `transactions`, describes the setup action (e.g. "Switch e-mode to 1"). |
| `actions.permissions` | object[] | Approval/delegation transactions that must execute before both `transactions` and `alternatives`. Includes ERC20 allowances (targeting the composer contract) and lender borrow/withdrawal delegations (targeting the lending protocol contract directly). Filtered against on-chain state so only missing approvals are returned. Null when no approvals are needed. |
| `actions.permissions[].to` | string | Target contract address |
| `actions.permissions[].data` | string | Encoded calldata |
| `actions.permissions[].value` | string | ETH value |
| `actions.permissions[].description` | string | Human-readable description of the approval (e.g. "Approve borrow for AAVE_V3", "Approve ERC20") |
| `actions.permissions[].spender` | string | ERC-20 approve spender (x-chain permissions). Match it against the selected quote's `approvalTarget` — several bridges can share one spender, so do not match by description. |
| `actions.permissions[].type` | "ERC20" \| "Lender" | What kind of grant this is. A `signatures[]` offer names the `type` it replaces via its `replaces` field. |
| `actions.signatures` | object[] | EIP-712 payloads the user can sign INSTEAD of sending the corresponding `permissions` entry. Only present when the caller opted in with `permit=auto\|required` and a permit path exists. Sign with `eth_signTypedData_v4`, then POST the same endpoint with `{permits: [{permitId, signature}]}` (plus `builds` where the response issued buildIds) — the permit executes inside the main transaction. |
| `actions.signatures[].permitId` | string | Opaque, self-describing handle for this permit. Round-trip it verbatim: POST `{permits: [{permitId, signature}]}` back to the same endpoint. |
| `actions.signatures[].kind` | "erc2612" \| "dai" \| "permit2" \| "aaveCredit" \| "morphoAuth" \| "cometAuth" | Permit flavour |
| `actions.signatures[].typedData` | object | Ready for `eth_signTypedData_v4` (domain, types incl. EIP712Domain, primaryType, message). All numeric fields are decimal strings. |
| `actions.signatures[].replaces` | string | Which `permissions` entry this signature replaces (`ERC20` \| `Lender`) |
| `actions.signatures[].spender` | string | Who the signature authorises. Match against the permission / quote (`approvalTarget`) it replaces — on multi-spender responses (x-chain) only routes whose approvalTarget equals this spender are covered by the signature. |
| `actions.signatures[].description` | string | Human-readable label for this entry. |
| `actions.signatures[].unscoped` | boolean | True when the grant is NOT amount-scoped (full position control until revoked) — surface this to the user. |
| `actions.signatures[].deadline` | string | Unix seconds after which the signature is worthless (default: 30 minutes). |
| `actions.signs` | object[] | Messages that MUST be signed before anything can be sent (unlike `signatures`, which are optional permit offers). When non-empty, `transactions` and `alternatives` are EMPTY: sign `typedData` with `eth_signTypedData_v4` (or, for `format: personal_sign`, `message` with `personal_sign`), then call `submit` with the signature under `submit.signatureField`, and execute what that answers. `permissions` may still be present and can be sent before or after signing. Produced by Inverse FiRM loops (`/loop/leverage`, `/loop/close`), Morpho Midnight make, Term order-sign and the Lista leg of `/rewards/claim`. |
| `actions.signs[].purpose` | "authorize-action" \| "publish-order" \| "authenticate" | `authorize-action`: the signature authorises an on-chain action and `submit` answers its transaction (Inverse ALE loops). `publish-order`: the signature makes an off-chain order and `submit` publishes it (Midnight make, Term order-sign). `authenticate`: the signature is a LOGIN to a third-party API that serves the data the transaction needs (Lista reward proofs); it authorises nothing on-chain. |
| `actions.signs[].format` | "eip712" \| "personal_sign" | `eip712`: sign `typedData` with `eth_signTypedData_v4`. `personal_sign`: sign the UTF-8 `message` with `personal_sign`. |
| `actions.signs[].typedData` | object | `format: eip712` only. Ready for `eth_signTypedData_v4`. All numeric fields are decimal strings. |
| `actions.signs[].message` | string | `format: personal_sign` only. The exact text to sign; send it back verbatim (it is part of `submit.params`). |
| `actions.signs[].signer` | string | The address that must sign. The server recovers the signer and refuses any other. |
| `actions.signs[].deadline` | string | Unix seconds after which the signature is worthless. |
| `actions.signs[].spender` | string | Who the signature authorises. |
| `actions.signs[].description` | string | Human-readable label for this entry. |
| `actions.signs[].submit` | object |  |
| `actions.signs[].submit.method` | "GET" \| "POST" |  |
| `actions.signs[].submit.endpoint` | string | Path on this API, e.g. `/v1/actions/loop/leverage`. |
| `actions.signs[].submit.params` | object | GET: the complete query to send — the original request plus the handle the signature is for (`permitId`). Replay verbatim. |
| `actions.signs[].submit.body` | object | POST: the JSON body to send, verbatim. |
| `actions.signs[].submit.signatureField` | string | The query param (GET) or body field (POST) that carries the signature. |
| `actions.permitSkipped` | object[] | Why a permit was NOT offered for a permission, when one was asked for (`permit=auto\|required`). The corresponding approve transaction stands. |
| `actions.permitSkipped[].replaces` | string | Which permission kind stays a transaction (`ERC20` \| `Lender`) |
| `actions.permitSkipped[].reason` | string |  |

**Example response**

```json
{
  "success": true,
  "data": {},
  "actions": {
    "transactions": [
      {
        "chainType": "evm",
        "to": "0x87870Bca3F3fD6335C3F4ce8392D69350B4fA4E2",
        "data": "0x617ba037000000000000000000000000c02aaa39b2",
        "value": "0",
        "description": "string"
      }
    ],
    "alternatives": [
      {
        "chainType": "evm",
        "to": "0x87870Bca3F3fD6335C3F4ce8392D69350B4fA4E2",
        "data": "0x617ba037000000000000000000000000c02aaa39b2",
        "value": "0",
        "description": "string"
      }
    ],
    "permissions": [
      {
        "to": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "data": "0x617ba037000000000000000000000000c02aaa39b2",
        "value": "0",
        "description": "string",
        "spender": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "type": "ERC20"
      }
    ],
    "signatures": [
      {
        "permitId": "string",
        "kind": "erc2612",
        "typedData": {},
        "replaces": "string",
        "spender": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "description": "string",
        "unscoped": true,
        "deadline": "string"
      }
    ],
    "signs": [
      {
        "purpose": "authorize-action",
        "format": "eip712",
        "typedData": {},
        "message": "string",
        "signer": "string",
        "deadline": "string",
        "spender": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "description": "string",
        "submit": {
          "method": "GET",
          "endpoint": "string",
          "params": {},
          "body": {},
          "signatureField": "string"
        }
      }
    ],
    "permitSkipped": [
      {
        "replaces": "string",
        "reason": "string"
      }
    ]
  }
}
```

**Response `400`** — Validation error

**Response `429`** — Rate limited. Unauthenticated callers share a per-IP budget; send an `x-api-key` header to lift it. Retry with exponential backoff.

**Response `500`** — Unexpected server error. Safe to retry with backoff.

**Response `502`** — An upstream data source or protocol origin failed (`error.code` is `ORIGIN_FAILED`). `error.details` carries the per-origin status. This is also what a missing or malformed required parameter currently returns, rather than a 400.