Search every new sign-up selfie against the gallery of prior approved selfies. A match means the same human already has an account. Face Search is free; 500 verifications free every month.
Robinhood Ventures
Trusted by 2,000+ organizations worldwide.
What email and phone cannot catch
Email aliases and burner SIMs cost cents. A human face is the one identifier the sybil farmer cannot rotate. Face Search 1:N against your prior-selfie gallery makes the same person impossible to hide. Free per search, 500 verifications free every month.
Pick the checks you want, ID, liveness, face match, sanctions, address, age, phone, email, custom questions. Drag them into a flow in the dashboard, or post the same flow to our API. Branch on conditions, run A/B tests, no code required.
Embed natively with our Web, iOS, Android, React Native, or Flutter SDK. Redirect to a hosted page. Or just send your user a link, by email, SMS, WhatsApp, anywhere. Pick what fits your stack.
Didit hosts the camera, the lighting cues, the mobile hand-off, and accessibility. While the user is in the flow, we score 200+ fraud signals in real time and verify every field against authoritative data sources. Result in under two seconds.
Real-time signed webhooks keep your database in sync the moment a user is approved, declined, or sent to review. Poll the API on demand. Or open the console to inspect every session, every signal, and manage cases your way.
Didit · Sybil patterns
Didit · Face Search 1:N
Sign-up · 2 / 2
Searching the gallery
Didit · Face Search verdict
Didit · Cross-account link
Didit · Reusable KYC
First KYC
Anchor
Didit · Webhook · X-Signature-V2
{
"session_id": "new-abc",
"vendor_data": "signup-A4",
"status": "Declined",
"face_search": {
"matches": [
{ "session_id": "sess-9182",
"similarity": 0.96 }
]
}
}$ curl -X POST https://verification.didit.me/v3/session/ \
-H "x-api-key: $DIDIT_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"workflow_id": "wf_sybil_gate",
"vendor_data": "signup-A4",
"metadata": { "surface": "airdrop_claim" }
}'status: Approved.docs →// X-Signature-V2 verified upstream
if (payload.status === "Declined") {
logCluster(payload.face_search.matches);
blockSignup(payload.vendor_data);
} else if (payload.status === "In Review") {
queueForAnalyst(payload);
}X-Signature-V2 before reading the payload.docs →You are integrating Didit Face Search 1:N to catch the same human opening many accounts on your platform — sybil airdrops, referral payout cycles, sign-up bonus stacking, iGaming multi-accounting that bypasses self-exclusion, marketplace fake-review clusters. One API call. One signed webhook. One decision.
WHY THIS SHAPE
- Email, phone, device, IP can all be rotated cheaply. A human face cannot.
- Every new sign-up captures one Passive Liveness selfie. Didit searches that selfie against the gallery of prior approved selfies under your account. A high-similarity match means the same person already has an account.
- Face Search 1:N itself is FREE on every session — no per-search fee. Only the surrounding bundle (ID + Passive Liveness + AML) carries the usual cost. Use the full Know Your Customer (KYC) bundle on sign-up or the Passive Liveness + Face Search subset, depending on what the product needs.
PRE-REQUISITES
- Production API key from https://business.didit.me (sandbox key in 60 seconds, no credit card).
- A webhook endpoint with HMAC SHA-256 verification of the X-Signature-V2 header using your webhook secret.
- A Workflow Builder workflow that contains the Face Search 1:N module. Compose it with Passive Liveness so an attacker cannot upload a still photo of the target.
- Define what a "match" means for your product. Default: similarity ≥ 0.85 = Declined. 0.75–0.85 = In Review. < 0.75 = Approved.
STEP 1 — Open the sign-up session
POST https://verification.didit.me/v3/session/
Headers:
x-api-key: <your api key>
Content-Type: application/json
Body:
{
"workflow_id": "<wf id with Face Search 1:N + Passive Liveness>",
"vendor_data": "<your new-account id, max 256 chars>",
"callback": "https://<your-app>/sybil-gate/callback",
"metadata": {
"surface": "airdrop_claim",
"campaign": "<your campaign id>"
}
}
Response: 201 Created with a hosted session URL. Redirect inline (web) or open in a Software Development Kit (SDK) webview (mobile). The new account stays UNCREATED on your side until the signed webhook lands.
STEP 2 — Read the signed webhook
Didit POSTs the verdict. Verify X-Signature-V2 (HMAC SHA-256 of the raw body) BEFORE reading the JSON.
Payload (excerpted, match case):
{
"session_id": "<uuid>",
"vendor_data": "<your new-account id>",
"status": "Declined",
"face_search": {
"matches": [
{ "session_id": "sess-9182", "similarity": 0.96, "vendor_data": "user-A1" },
{ "session_id": "sess-7733", "similarity": 0.94, "vendor_data": "user-A2" }
]
}
}
Session status enum (exact case, Title Case With Spaces): Approved | Declined | In Review | Resubmitted | Expired | Not Finished | Kyc Expired | Abandoned.
STEP 3 — Branch the sign-up
Approved → no gallery match. Create the account.
In Review → soft match (similarity in your grey-zone band). Queue for human review.
Declined → hard match (similarity above your hard threshold). Block, log the matched session_id list as the audit trail.
STEP 4 — Cross-account link signals (optional but cheap)
Compose Device & IP Analysis ($0.03 / call) in the same workflow. The decision payload surfaces device fingerprint, IP, Autonomous System Number (ASN), country, and city. Combine with your own payment-instrument hash and you can cluster sybils even before the face search confirms.
STEP 5 — Reusable KYC for legitimate cross-product re-entry
If the user is supposed to reuse one identity across multiple products you own, Reusable KYC lets them replay a previously verified credential at no cost. That is different from sybil abuse — reuse is intentional and you control the issuance.
WEBHOOK EVENT NAMES
- Sessions: standard session webhook. One endpoint, status field tells you the lifecycle.
- Verify X-Signature-V2 (HMAC SHA-256) on every payload.
WHAT IT BLOCKS
- Sybil airdrop / token claims (one person · many wallets)
- Self-referral payout cycles (sign-up bonus farms)
- iGaming multi-accounting that bypasses self-exclusion
- Marketplace fake-review clusters from a single human
- DAO and community-vote stuffing
- Welcome-bonus stacking on neobank / brokerage sign-ups
CONSTRAINTS
- Session statuses use Title Case With Spaces. Never UPPER_SNAKE_CASE for session verdicts — that's the Transactions API.
- Face Search 1:N WITHOUT Passive Liveness lets an attacker upload a still photo of the target. Always compose them together.
- Thresholds are tunable per workflow. Start at 0.85 hard / 0.75 soft and adjust based on your false-positive tolerance.
- The gallery is scoped to your account — no cross-customer leakage by design.
Read the docs:
- https://docs.didit.me/sessions-api/create-session
- https://docs.didit.me/core-technology/face-search/overview
- https://docs.didit.me/core-technology/liveness/overview
- https://docs.didit.me/integration/webhooks
Start free at https://business.didit.me — sandbox key in 60 seconds, 500 verifications free every month, no credit card.$0 / month. No credit card required.
Pay only for what you use. 25+ modules. Public per-module pricing, no monthly minimum fee.
Custom MSA & SLA. For large volumes and regulated programs.
Start free → pay only when a check runs → unlock Enterprise for a custom contract, SLA, or data residency.
Didit is infrastructure for identity and fraud, the platform we wished existed when we were building products ourselves: open, flexible, and developer-friendly, so it works as a real part of your stack instead of a black box you integrate around.
One API covers verifying people (KYC, know your customer), verifying businesses (KYB, know your business), screening crypto wallets (KYT, know your transaction), and monitoring transactions in real time, on a stack built to be:
The footprint underneath: 14,000+ document types in 48+ languages, 1,000+ data sources, and 200+ fraud signals on every session. The Didit infrastructure dynamically learns from every session and gets better every day.
A sybil attack is when one human creates many accounts to pretend to be many humans. The name comes from a 1973 case study of a patient with dissociative identity disorder. In product terms it shows up as one person claiming an airdrop ten times, stacking ten sign-up bonuses, or stuffing a leaderboard with ten "different" wins.
The attack works because every other identifier, email, phone, device, Internet Protocol (IP) address, can be rotated for cents. The one identifier that cannot be cheaply rotated is the attacker's own face.
A sybil farmer in 2026 can buy:
The whole operation pays back if a single sybilled airdrop or bonus is worth more than the kit. Face Search 1:N takes the face, the one thing the farmer cannot cheaply duplicate, and turns it into the unique key.
The full flow normally takes under 30 seconds end-to-end, pick up the ID, snap the document, snap the selfie, done. That is the fastest in the market. Legacy KYC providers usually take more than 90 seconds for the same flow.
On the back end, Didit returns the result in under two seconds at p99, measured from the moment the user finishes the selfie to the moment your webhook fires. Mobile capture is tuned for slow phones and slow networks: progressive image compression, lazy software development kit load, and a one-tap hand-off from desktop to phone via QR code if the user starts on web.
Different question, different math.
The 1:1 check costs \$0.05 per match. Face Search 1:N is free per search, only the surrounding bundle (ID Verification, Passive Liveness) carries cost.
Every session lands on one of seven clear statuses, so your code always knows what to do:
Approved, every check passed. Move the user forward.Declined, one or more checks failed. You can allow the user to resubmit the specific failed step (for example, re-take the selfie) without re-running the whole flow.In Review, flagged for compliance review. Open the case in the console, see every signal, decide approve or decline.In Progress, user is mid-flow.Not Started, link sent, user has not opened it yet. Send a reminder if it sits too long.Abandoned, user opened the link but did not finish in time. Re-engage or expire.Expired, the session link aged out. Create a new session.A signed webhook fires on every status change, so your database always stays in sync. Abandoned and declined sessions are free.
Production data is processed and stored in the European Union by default, on Amazon Web Services. Enterprise contracts can request alternative regions for jurisdictions whose regulators require it.
Encryption everywhere. AES-256 at rest across every database, object store, and backup. Transport Layer Security 1.3 in transit on every API call, webhook, and Business Console session. Biometric data is encrypted under a separate Customer Master Key.
Retention is yours to control. Default retention is indefinite (unlimited) unless you configure shorter, between 30 days and 10 years per application, and you can delete any individual session at any time from the dashboard or the API.
Certifications: SOC 2 Type 1 (Type 2 audit in progress), ISO/IEC 27001:2022, iBeta Level 1 PAD, and a public attestation from Spain''s Tesoro / SEPBLAC / CNMV that Didit''s remote identity verification is safer than verifying someone in person. Full report at /security-compliance.
Didit ships compliant by default for the regulators that matter to identity infrastructure:
Detailed memo, every certificate, every regulator letter: /security-compliance.
Three integration paths, pick whichever fits your stack:
Same dashboard, same billing, same pay-per-success price for all three. Step-by-step guide at docs.didit.me/integration/integration-prompt.
Face Search 1:N returns a similarity score between 0 and 1 per match. You set two thresholds per workflow:
Declined. Auto-block the sign-up.In Review. Queue for analyst.Approved. No duplicate found.Start at the defaults. If you see too many false positives (real twins, real strong family resemblance), raise the hard threshold. If duplicates slip through, lower it. Tune in the Workflow Builder, no redeploy needed.
Two line items per new sign-up:
Around \$0.10 per protected sign-up. Add Device & IP Analysis at \$0.03 if you want device + IP link signals for clustering. The first 500 verifications every month are free on every account.
No minimums, no annual commitment, no per-seat pricing.
Anywhere multiplying accounts has economic value:
One integration, every surface.
One API for KYC, KYB, Transaction Monitoring, and Wallet Screening. Integrate in 5 minutes.