> ## Documentation Index > Fetch the complete documentation index at: https://docs.didit.me/llms.txt > Use this file to discover all available pages before exploring further. # Start a Wallet-Ownership Proof API - Travel Rule Widget > Start a wallet-ownership proof from a widget session token: message signing, Satoshi test, screenshot or self-declaration. Picking a method again resumes it. Start Widget Proof API Prompt Copy prompt to clipboard 
  \`Start a wallet-ownership proof for a widget session. This is the call the hosted widget makes when the end user picks a proof method; use it only if I build my own widget UI.

  Endpoint:
  POST [https://verification.didit.me/v3/travel-rule/widget/\{token}/proofs/](https://verification.didit.me/v3/travel-rule/widget/\{token}/proofs/)

  Authentication:
  None - the widget token in the URL path is the credential. Treat the token as a secret.

  Body:

  * method - one of the context's allowed\_methods: MESSAGE\_SIGNING, SATOSHI\_TEST, SCREENSHOT or SELF\_DECLARATION.
  * wallet\_address, chain - optional, default to the session's.

  Behavior:

  * 201 with a new PENDING proof. MESSAGE\_SIGNING returns the challenge to sign; SATOSHI\_TEST returns deposit\_address, expected\_amount and expires\_at; SELF\_DECLARATION is verified at once.
  * 200 with the proof already open when the same method is picked again (same challenge or amount): resume it, do not treat it as an error.
  * Picking another method closes the unfinished proof as METHOD\_SWITCHED, except a submitted screenshot or a test deposit still being checked.
  * After a REJECTED proof, picking a method starts a new one (201). A session takes a limited number of rejected proofs: the context reports max\_attempts, attempts\_used and attempts\_remaining.
  * Message signing works on EVM chains (Ethereum, BNB Chain, Polygon, Arbitrum, Base, Optimism, Avalanche, Linea and others), Bitcoin (BIP-137 and BIP-322 simple), Solana and Tron.

  Failure modes (errors carry a code to translate):

  * 400 - code CHAIN\_UNSUPPORTED when the method is not available on the chain; also an invalid body or a wallet that does not match the transfer.
  * 403 - SELF\_DECLARATION not allowed for the application.
  * 409 - code OWNERSHIP\_CHANGED: mint a new session for the current holder.
  * 409 - no attempts left (no code; the body carries attempts\_remaining 0): mint a new session.
  * 404 - unknown token. 410 - the session expired.

  Full guide: /transaction-monitoring/wallet-ownership-widget#what-it-proves.\`
Paste into ## OpenAPI ````yaml POST /v3/travel-rule/widget/{token}/proofs/ openapi: 3.0.0 info: version: 3.0.0 title: Didit Verification API description: Identity verification API. Authenticate with x-api-key header. servers: - url: https://verification.didit.me security: [] tags: [] paths: /v3/travel-rule/widget/{token}/proofs/: post: tags: - Travel Rule summary: Start a wallet-ownership proof description: >- Public endpoint keyed by the widget session token, no API key required: the hosted widget calls it when the end user picks a proof method. A proof exists, and counts in your proof funnel, only from this call. Picking the same method again returns the proof already open (200, same challenge or deposit amount) instead of starting a second one; picking another method closes the unfinished one as METHOD_SWITCHED, except a submitted screenshot or a test deposit still being checked. MESSAGE_SIGNING returns the challenge to sign; SATOSHI_TEST the deposit address, exact amount and window; SELF_DECLARATION is verified at once (status VERIFIED). Signature formats verified per chain family: EVM chains take a personal_sign (EIP-191) signature, hex encoded; Bitcoin takes a BIP-137 signmessage signature (P2PKH, P2SH-P2WPKH and P2WPKH addresses) or a BIP-322 simple signature (P2WPKH and P2TR addresses), base64 encoded; Solana takes an Ed25519 signature over the challenge, base58 encoded; Tron takes a signMessageV2 (TIP-191) signature, hex encoded. A BIP-322 full or proof-of-funds signature, or a multisig address, fails with SIGNATURE_UNSUPPORTED_SCHEME. operationId: createTravelRuleWidgetProof parameters: - name: token in: path required: true description: Opaque session token returned when the widget session was minted. schema: type: string requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/TravelRuleWidgetProofCreate' responses: '200': description: The proof already open for this method, resumed. content: application/json: schema: $ref: '#/components/schemas/TravelRuleWidgetProofSummary' '201': description: A new PENDING proof (VERIFIED for SELF_DECLARATION). content: application/json: schema: $ref: '#/components/schemas/TravelRuleWidgetProofSummary' '400': description: >- Invalid body, a wallet that does not match the transfer, SCREENSHOT not allowed, or code CHAIN_UNSUPPORTED when the method is not available on the chain. content: application/json: schema: $ref: '#/components/schemas/TravelRuleWidgetProofError' '403': description: SELF_DECLARATION is not allowed for this application. '404': description: Unknown token. '409': description: >- code OWNERSHIP_CHANGED: the wallet's holder changed or the wallet was deleted after the session was minted; mint a new session for the current holder. Also returned for SATOSHI_TEST when the session has no satoshi_deposit_address, and when the session has no attempts left (no code; the body carries max_attempts, attempts_used and attempts_remaining 0): mint a new session. content: application/json: schema: $ref: '#/components/schemas/TravelRuleWidgetProofError' '410': description: The session expired. security: - {} x-codeSamples: - lang: curl label: curl source: >- curl -X POST https://verification.didit.me/v3/travel-rule/widget/{token}/proofs/ \ -H 'Content-Type: application/json' \ -d '{"method": "MESSAGE_SIGNING"}' components: schemas: TravelRuleWidgetProofCreate: type: object required: - method properties: method: type: string enum: - MESSAGE_SIGNING - SATOSHI_TEST - SCREENSHOT - SELF_DECLARATION description: >- The proof method the end user picked. It must be one of the context's allowed_methods. wallet_address: type: string maxLength: 128 description: >- Defaults to the session's wallet_address. Must match the transfer's wallet when the session is linked to a transfer. chain: type: string maxLength: 32 description: Defaults to the session's chain. TravelRuleWidgetProofSummary: type: object properties: proof_id: type: string format: uuid method: type: string enum: - MESSAGE_SIGNING - SATOSHI_TEST - SCREENSHOT - SELF_DECLARATION status: type: string enum: - PENDING - VERIFIED - REJECTED - EXPIRED description: >- PENDING: the end user picked this method and the proof is not decided yet. A failed signature or a test deposit that is not readable or confirmed yet keeps the proof PENDING with a failure_reason, so the end user can try again; a submitted SATOSHI_TEST deposit is rechecked automatically until its window closes, and a submitted SCREENSHOT waits for your review. VERIFIED: ownership is proven. REJECTED: the test deposit is genuinely wrong (another sender, not the expected amount to the deposit address, older than the challenge, or a transaction that already proved another wallet) or your reviewer rejected the screenshot; failure_reason says which. A rejected proof is final and uses one of the session's attempts. EXPIRED: the proof can no longer be decided (its window closed, the end user switched method, the widget session lapsed, or the wallet's holder changed); failure_reason says which. wallet_address: type: string chain: type: string description: >- Canonical chain identifier of the address book entry the proof is for, e.g. ETH, BTC, SOL, TRX. deposit_address: type: string nullable: true description: >- Deposit address the customer must send the Satoshi test amount to. Present only on a SATOSHI_TEST proof. expected_amount: type: string nullable: true description: >- Exact on-chain amount, in the deposit's native currency, the Satoshi test deposit must match. Present only on a SATOSHI_TEST proof. expires_at: type: string format: date-time nullable: true description: >- Deadline for this proof's own Satoshi test window. Present only on a SATOSHI_TEST proof; the widget session's own expires_at is extended to cover it when SATOSHI_TEST is offered. challenge: type: string nullable: true description: >- Didit-issued message the customer signs with their wallet. Present only on a MESSAGE_SIGNING proof. rejection_reason: type: string description: >- Why the proof was rejected, as an English sentence for the end user. Present only when `status` is REJECTED; empty when your reviewer rejected a screenshot (your note stays with you). created_at: type: string format: date-time attempts: type: integer description: >- How many times evidence was submitted for this proof (signatures, transaction ids, uploads). failure_reason: allOf: - $ref: '#/components/schemas/TravelRuleWalletProofFailureReason' description: >- Why the last attempt fell short, or why the proof closed. Empty when nothing failed. TravelRuleWidgetProofError: type: object properties: detail: type: string description: Human-readable message in English. code: allOf: - $ref: '#/components/schemas/TravelRuleWalletProofFailureReason' description: >- Machine-readable reason, so a client can show its own translated message. status: type: string enum: - PENDING - VERIFIED - REJECTED - EXPIRED description: >- Present when the proof is closed: REJECTED by the deposit just submitted (400), or REJECTED or EXPIRED when evidence is sent to a proof that is already closed (409). proof_id: type: string format: uuid description: 'Present with status: the closed proof.' method: type: string enum: - MESSAGE_SIGNING - SATOSHI_TEST - SCREENSHOT - SELF_DECLARATION description: 'Present with status: the closed proof''s method.' max_attempts: type: integer description: 'Present with status: rejected wallet proofs this session allows.' attempts_used: type: integer description: 'Present with status: rejected proofs so far.' attempts_remaining: type: integer description: >- Present with status: when 0, starting another proof answers 409 and you mint a new widget session. TravelRuleWalletProofFailureReason: type: string enum: - '' - SIGNATURE_INVALID - SIGNATURE_UNSUPPORTED_SCHEME - DEPOSIT_NOT_FOUND - DEPOSIT_UNCONFIRMED - DEPOSIT_LOOKUP_FAILED - DEPOSIT_MISMATCH - DEPOSIT_STALE - TXID_REUSED - CHAIN_UNSUPPORTED - WINDOW_EXPIRED - OWNERSHIP_CHANGED - METHOD_SWITCHED - REVIEW_REJECTED - ABANDONED description: >- Why a wallet-ownership proof, or its last attempt, fell short of VERIFIED. Empty when nothing failed. A PENDING proof can carry one: the last attempt failed and the end user can try again. DEPOSIT_MISMATCH, DEPOSIT_STALE, TXID_REUSED and REVIEW_REJECTED close the proof as REJECTED. SIGNATURE_INVALID: the signature does not match the wallet and challenge. SIGNATURE_UNSUPPORTED_SCHEME: the wallet signed in a format Didit does not verify. DEPOSIT_NOT_FOUND, DEPOSIT_UNCONFIRMED, DEPOSIT_LOOKUP_FAILED: the test deposit is not readable or not confirmed yet; Didit keeps checking it until the test window closes. DEPOSIT_MISMATCH: the transaction does not send the expected amount from the wallet to the deposit address. DEPOSIT_STALE: the transaction predates the challenge. TXID_REUSED: the transaction already proved another wallet. CHAIN_UNSUPPORTED: the method is not available on this chain. WINDOW_EXPIRED: the test window closed. OWNERSHIP_CHANGED: the wallet's holder changed, or the wallet was deleted from your address book, after the widget session was minted. METHOD_SWITCHED: the end user picked another method before finishing this one. REVIEW_REJECTED: your reviewer rejected the screenshot. ABANDONED: the widget session lapsed before the end user finished. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.