Injective Frontend Wallet

Use this skill before shipping any Injective browser transaction flow. Injective looks Cosmos-shaped at the transaction layer, but its accounts and public keys are Ethereum-style. Generic Cosmos frontend code often reaches the quote screen and then fails at signing or CheckTx.

First Decision

Choose the signing stack deliberately:

1. Prefer @injectivelabs/sdk-ts / Injective broadcaster utilities when the app already uses the Injective SDK and the transaction type is covered.
2. Use CosmJS for CosmWasm frontends only if you explicitly handle Injective account and pubkey compatibility.
3. Do not assume a Keplr/Leap inj1... address means generic /cosmos.crypto.secp256k1.PubKey signing will validate on-chain.

Required Checks

Before calling the work complete, verify these on the actual signing path:

• Query account metadata from LCD: GET /cosmos/auth/v1beta1/accounts/{injAddress}.
• If the account @type is /injective.types.v1beta1.EthAccount, parse base_account.account_number and base_account.sequence; do not rely on CosmJS' default accountFromAny.
• Ensure transaction AuthInfo.signer_infos[0].public_key.type_url is /injective.crypto.v1beta1.ethsecp256k1.PubKey.
• Ensure the public key bytes are encoded as protobuf field 1 (0a <len> <compressed-pubkey>), same field shape as the standard secp256k1 key but with the Injective type URL.
• For direct signing, sign the SignDoc that contains that Injective pubkey in authInfoBytes; otherwise the wallet signs bytes that differ from the broadcast transaction.
• Use the wallet address returned for chain injective-1; do not derive or substitute addresses from another chain account without conversion checks.

Browser Trading Flow Checks

Browser trading apps need UI-level guards in addition to correct signing bytes:

• Keep a single per-wallet in-flight lock around transaction-producing actions. Disable open, close, cash-out, and bulk action buttons until the prior tx is confirmed or has failed.
• Do not rely on per-card loading state to prevent duplicate broadcasts; two buttons can still race the same account sequence.
• Revalidate any local session, grantee, or autosign token against the currently connected inj1 address after wallet connect, account swap, and page reload.
• Treat account sequence mismatch, expected X, got Y as a likely concurrency bug first. Audit parallel clicks, multiple tabs, stale cached sequence, and background retries before changing chain parameters.
• Keep raw CheckTx details in logs. User-facing errors should explain the action, such as Order failed, please try again., not expose transaction hashes, RFQ IDs, account sequences, or signer internals.

Common Failures

If the error is:

• Unsupported type: '/injective.types.v1beta1.EthAccount': the client is using a generic Cosmos account parser for sequence/account number. Patch getSequence() or use Injective SDK account querying.
• pubKey does not match signer address ... invalid pubkey: AuthInfo likely contains /cosmos.crypto.secp256k1.PubKey; use /injective.crypto.v1beta1.ethsecp256k1.PubKey.
• account does not exist on chain: the wallet has never transacted or is unfunded. Fund it with INJ and retry after the account exists.
• signature verification failed: inspect sign mode, signed authInfoBytes, account number, sequence, and chain ID before changing business logic.

CosmJS Compatibility Pattern

When using SigningCosmWasmClient against Injective:

1. Connect with the wallet signer.
2. Patch or wrap getSequence(address) so it reads account number and sequence from Injective LCD for EthAccount.
3. Patch direct signing so AuthInfo uses the Injective ethsecp pubkey type URL.
4. Keep the actual business message unchanged, such as MsgExecuteContract for a swap contract.
5. Add unit tests for the account payload and pubkey encoding helpers.

Minimal helper expectations:

const INJECTIVE_PUBKEY_TYPE = "/injective.crypto.v1beta1.ethsecp256k1.PubKey";
const INJECTIVE_ACCOUNT_TYPE = "/injective.types.v1beta1.EthAccount";

Swap Contract Frontends

For Injective swap-contract UIs:

• Query the contract for routes and quotes; do not inspect orderbooks in the browser unless the task explicitly requires independent analytics.
• Execute the swap contract message (swap_min_output or swap_exact_output) with exactly one input coin in funds.
• Keep RFQ and direct exchange-module order placement out of scope unless the user asks for those venues.
• Apply slippage to the contract quote's raw output quantity, not the formatted decimal string.
• Test a live quote and a dry signing-path construction before asking the user to sign real funds.

Regression Checklist

Add at least these tests or harness checks:

• Parse an Injective EthAccount LCD fixture into { accountNumber, sequence }.
• Encode an Injective ethsecp pubkey and assert the type URL exactly.
• Build a tx or signing harness and assert authInfoBytes contains the Injective pubkey type before broadcast.
• Run typecheck, unit tests, and a production build for browser apps.

Do Not Ship Until

• The account type and pubkey type checks above have been run.
• The transaction path has been tested with the same wallet family the user will use, typically Keplr or Leap for inj1.
• Any fallback to generic CosmJS behavior is documented as unsafe for Injective unless proven with the checks above.