Attestic

Developer Guide

If you use the OpenAI SDK, you are 3 lines away. Every call gets a signed, verifiable receipt.

1. Get a key

Sign up at /signup, then mint an API key at /api-keys. Keys start with atk_.

2. Python (OpenAI SDK)

python
from openai import OpenAI

client = OpenAI(
    base_url="https://atherion-gateway-924270273440.us-central1.run.app/v1",
    api_key="atk_your_key_here",
)

response = client.chat.completions.create(
    model="gpt-5.5",   # or claude-opus-4-8, gemini-3.1-pro-preview,
    messages=[         #    meta/llama-3.3-70b-instruct, ...
        {"role": "user", "content": "Explain provenance in one sentence."}
    ],
)
print(response.choices[0].message.content)
# Signed receipt in response headers: x-attestic-receipt-id

3. Verify a receipt offline

Every call returns x-attestic-receipt-id. Fetch the bundle and verify the Ed25519 signature + Merkle proof, no Attestic access required.

python, offline verification
import hashlib, urllib.request, json
from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey

GW = "https://atherion-gateway-924270273440.us-central1.run.app"
bundle = json.load(urllib.request.urlopen(urllib.request.Request(
    f"{GW}/v1/receipts/YOUR_RECEIPT_ID",
    headers={"Authorization": "Bearer atk_your_key"}
)))

# Verify Ed25519 signature
pk = Ed25519PublicKey.from_public_bytes(bytes.fromhex(bundle["public_key"]))
pk.verify(bytes.fromhex(bundle["signature"]), bytes.fromhex(bundle["signed_bytes"]))

# Verify Merkle inclusion
h = bytes.fromhex(bundle["merkle"]["leaf_hash"])
for step in bundle["merkle"]["proof"]:
    sib = bytes.fromhex(step["sibling"])
    h = hashlib.sha256((sib + h) if step["side"] == "left" else (h + sib)).digest()
assert h.hex() == bundle["merkle"]["root"]   # ✓ verified offline

Models

Route by model id: gpt-5.5, claude-opus-4-8, gemini-3.1-pro-preview, meta/llama-3.3-70b-instruct. GET /v1/models?live=1 returns the real current list from each provider.

Streaming

stream:true works across all providers. The final SSE chunk includes attestic_provenance (receipt_id, entry_hash, signature, cost_usd) inline.

Tools & JSON mode

OpenAI-format tools translate to each provider's native schema. response_format:json_schema works on OpenAI and Gemini natively; best-effort on Anthropic.

Embeddings

POST /v1/embeddings routes text-embedding-3-* to OpenAI and gemini-embedding-* to Gemini. Same auth, same receipts, real token metering.