Managed proof-of-work challenges for modern sites

Privacy-first CAPTCHA without puzzles, tracking, or visual noise.

Blank Captcha gives product teams hosted challenge protection, project-level keys, usage limits, billing-aware enforcement, and a clean dashboard for day-to-day operations.

Free tier
100
verifications
Setup
5 min
to first widget
Data
EU
ready hosting
Active project

Checkout protection

pk_live_8Hk2...Qp4

Balanced

Issued

42k

Passed

41k

Blocked

418

Security preset
Balanced
Challenge engine
Synced

Widget preview

Looping preview
Verify you are human Calculating proof Verified Bot traffic blocked
Blank Captcha Ready Solving Passed Blocked
Engine
Ready
Billing limits
Enforced
Domains
example.com

Built for operational teams

Everything around the widget is handled.

Create projects, copy keys, manage domains, review usage, and keep billing limits aligned without exposing the challenge engine directly.

P

Project keys

Issue public sitekeys and backend secrets per project, with rotation and scoped domain controls.

U

Usage limits

Free, Starter, Business, and Enterprise limits are enforced across challenge, redeem, and verify paths.

E

Engine sync

Security presets, domain changes, project status, and deletes stay tied to the challenge engine.

B

Billing state

Stripe checkout, portal access, scheduled changes, invoices, payment status, and admin resync are built in.

O

Operator tools

Admins can review tenants, pending registrations, project status, failed webhooks, and audit history.

D

Developer handoff

Copy the widget snippet, backend verify endpoint, and styling variables directly from the project page.

Implementation workflow

From empty account to protected form.

The dashboard guides setup without hiding the operational details: project state, allowed domains, security presets, keys, usage, and server verification all stay visible.

01
Provision project keys
02
Restrict allowed domains
03
Copy widget and CSS
04
Verify tokens server-side

Project setup

Checkout protection

Synced
Project created
Done
Domain locked
example.com
Widget copied
Ready
Server verify
Pending

Security preset

Balanced

Monthly usage

418 / 1,000

Widget snippet

<blank-captcha data-sitekey="pk_live..."></blank-captcha>

Control plane

The backend is part of the product.

Blank Captcha is not just a script tag. Teams get the operational surface they need after launch: billing state, project health, engine sync, audit history, and admin recovery tools.

Project operations

Rename projects, update status, rotate secrets, resync the engine, and keep domains aligned.

Billing-aware limits

Plan limits are enforced across challenge, redeem, and verify paths with scheduled plan changes visible in the app.

Operator oversight

Review organizations, pending registrations, failed webhooks, audit events, and manual overrides from one place.

Developer handoff

Copy sitekeys, widget snippets, backend verify examples, and preview CSS variables from the project view.

Comparison

Less friction than puzzle-first CAPTCHA.

The goal is simple: keep bot pressure visible and controlled without making legitimate users solve image puzzles or giving teams another black box.

Capability
Puzzle-first tools
Captcha
User experience
Often asks users to classify images or solve visual tasks.
Runs a proof-of-work challenge with a small, quiet widget.
Team control
Configuration can live outside the product workflow.
Projects, domains, keys, billing, and usage live in one dashboard.
Privacy posture
May rely on third-party risk scoring or broader tracking surfaces.
Designed around self-hostable challenge infrastructure and minimal form friction.
Operations
Failures can be opaque for support and engineering teams.
Engine sync state, audit logs, and operator tools are visible.

Plans

Start small, keep the same integration.

Use the free tier for demos and internal forms, then scale usage limits as traffic grows.

Free

Free

100 verifications / month

For trying the platform and low-volume personal projects.

  • 1 project
  • Hosted widget asset
  • Basic project usage metrics
  • Community support
Start free

Starter

€5 / month

1,000 verifications / month

For small sites and early production projects.

  • 5 projects
  • Managed challenge engine
  • Project usage metrics
  • Hosted widget asset
Start Starter

Business

€15 / month

10,000 verifications / month

For production sites with regular customer traffic.

  • 25 projects
  • 10,000 monthly verifications
  • More projects
  • Priority support
Start Business

Enterprise

Contact sales

Custom verification volume

For higher-volume use cases and custom requirements.

  • Custom verification volume
  • Dedicated onboarding
  • Commercial support options
Contact sales

Protect your next form without adding friction.

Create a project, copy the snippet, and keep abuse controls visible from one dashboard.