Developer quickstart
The SDK is live right now — pip install or npm i. Verify any receipt for free, no account. Emit Article 50 receipts in a few lines. Buy a plan to get your key and anchor to the public chain today.
Python or TypeScript, your choice. Already on LangChain, OpenAI, Anthropic, Mistral, and more? Use the matching one-line adapter instead — see the adapter catalog.
# core SDK pip install ledgerproof # …or a framework adapter, e.g. LangChain pip install langchain-ledgerproof
npm install @ledgerproof/sdk
Apache-2.0. The protocol and verifier are open and free — owned by the LedgerProof Foundation (a California nonprofit; 501(c)(3) in process), which keeps them that way.
Verification needs no key, no account, and no call to LedgerProof. Drop a receipt into the open verifier, or do it in code. If LedgerProof disappeared tomorrow, every receipt still verifies.
# verify by the document's content hash — public, keyless from ledgerproof import verify_by_content_hash result = verify_by_content_hash("e3b0c44298fc1c14…") print(result.anchored, result.verify_url)
// verify by content hash — public, keyless import { lookupByContentHash } from "@ledgerproof/sdk"; const r = await lookupByContentHash("e3b0c44298fc1c14…"); console.log(r.anchored, r.verify_url);
Prefer a UI? Open verify.ledgerproofhq.io and drop in a receipt — it runs entirely in your browser.
Anchoring is the one part that needs a key — it's what your paid plan unlocks. Buy a plan, drop your key in an env var, and publish. The document is hashed locally; only the fingerprint is sent.
# LEDGERPROOF_API_KEY from your plan from ledgerproof import LedgerProof lp = LedgerProof(publisher_id="LEI:529900HNOAA1KXQJUQ27", deployer_country="DE") receipt = lp.publish_ai_article_50( artifact="the AI output text…", # hashed locally ai_system_id="support-bot", content_category="text", deployer_name="ACME GmbH", ) print(receipt.sequence, receipt.verify_url)
// LEDGERPROOF_API_KEY from your plan import { LedgerProof } from "@ledgerproof/sdk"; const lp = new LedgerProof({ publisherId: "LEI:529900HNOAA1KXQJUQ27", deployerCountry: "DE" }); const receipt = await lp.publishAiArticle50({ artifact: "the AI output text…", // hashed locally aiSystemId: "support-bot", contentCategory: "text", deployerName: "ACME GmbH", }); console.log(receipt.sequence, receipt.verify_url);
The receipt is signed with your key, queued for the next public-ledger anchor, and independently verifiable forever — no LedgerProof server in the verification path.
Drop-in adapters cover the major AI SDKs and orchestration frameworks — LangChain, LangGraph, OpenAI, Anthropic, Mistral, Cohere, Google AI, Bedrock, Azure OpenAI, LlamaIndex, Haystack, and more. Attach one callback; every call emits a receipt.
draft-dawkins-scitt-ai-article50, implementing the SCITT architectureVerification is always free and keyless. Anchoring requires a plan key. Receipts are tamper-evident, not tamper-proof. Not legal advice.