Sign your AI outputs with verifiable citation attestations.
Hosted CiteSig: one API call per response, an Ed25519 signature over the claim + sources, verifiable by anyone with the CiteSig Chrome extension or open-source verifier. 14-day free trial, no card required.
Sign up with email or Google. No card required for the free tier.
How it works
STEP 1
Sign up
14-day free trial (1,000 sigs) — no card required. Downgrades to Free (50 sigs/mo) at day 14 unless you upgrade.
STEP 2
Get your API key
One live key issued on signup. Displayed once — save it somewhere safe.
STEP 3
Call the signing API
POST /api/v1/sigs/sign with your claim + sources. Returns an attestation any verifier can check.
Pricing
Free
$0/mo
50 signatures/mo
1 sig/sec
Shared free-tier signer DID (watermarked).
POPULAR
Starter
$49/mo
1,000 signatures/mo
5 sigs/sec
Your own signer DID. Save 20% annually ($471/yr).
Growth
$179/mo
10,000 signatures/mo
20 sigs/sec
Your own signer DID. Save 20% annually ($1,719/yr).
Scale
$599/mo
100,000 signatures/mo
100 sigs/sec
Your own signer DID. Save 20% annually ($5,750/yr).
New accounts start on a 14-day Starter trial (no card required) and auto-downgrade to Free at day 14 unless you subscribe. Upgrade from your dashboard — monthly or annual, Stripe handles billing.
Verifiable by anyone
Signatures are open. Anyone can verify them with the CiteSig Chrome extension, the @citesig/core npm package, or the citesig PyPI package. Public keys are discoverable at /api/v1/sigs/keys.