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Before someone else does_

Feint attacks your APIs, cloud, CI and AI agents like a real adversary. It proves what it breaks with a working exploit and opens the pull request that fixes it.

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THE PRODUCT

Meet

Feint

Feint attacks your API, cloud, CI and AI agents the way a motivated adversary does: multi-step, stateful, adapting to what it finds. It finds the attack paths scanners and annual pentests miss, then opens the fix.

EXPLORE THE PRODUCT

USE IT FROM YOUR AGENT

Overview

Findings

Fixes

Reports

Overview

Findings

Fixes

Reports

HOW IT WORKS

Feint attacks an isolated copy of your environment the way a real adversary would. Only what actually works becomes a finding, and every finding ends in a merged fix.

Break it first.

Find it.

Fix it.

Keep it fixed.

01 · BREAK

Attacks your branch before you merge

Connect the Feint MCP server and Feint breaks your branch from Claude Code or Cursor. It speaks up only when it gets in.

Break

feat/export-v2no way in

feat/ssono way in

fix/webhooksno way in

feat/agent-toolsgot in

feat/billingno way in

1 of 5 branches breached

feat/agent-toolsGot in

Feint got in through a tool call

Claude Code

Finding opened in your session

● Fix it before you merge

01 · BREAK

Attacks your branch before you merge

Connect the Feint MCP server and Feint breaks your branch from Claude Code or Cursor. It speaks up only when it gets in.

Break

feat/export-v2no way in

feat/ssono way in

fix/webhooksno way in

feat/agent-toolsgot in

feat/billingno way in

1 of 5 branches breached

feat/agent-toolsGot in

Feint got in through a tool call

Claude Code

Finding opened in your session

● Fix it before you merge

02 · FIND

Exploitable, not theoretical

Every finding ships with a reproducible proof of exploit. 95% of scanner alerts never reach you, because Feint could not exploit them.

Find

1 exploit proved

CODE

export/job.ts trusts the body

INFRA

Job ids are sequential

AUTH

Tenant comes from the request

● Any tenant reads invoices

02 · FIND

Exploitable, not theoretical

Every finding ships with a reproducible proof of exploit. 95% of scanner alerts never reach you, because Feint could not exploit them.

Find

1 exploit proved

CODE

export/job.ts trusts the body

INFRA

Job ids are sequential

AUTH

Tenant comes from the request

● Any tenant reads invoices

03 · FIX

Fixes the root cause

One pull request per cause, covering every variant, with a regression test. Reviewed and merged like any other PR.

Fix

1 PR · 3 variants fixed

Same root cause3 findings

Job ids trusted the request body

PR #4821 change

Reviewed and merged by your team

Every variantFixed

Regression test added

● One PR, every variant

03 · FIX

Fixes the root cause

One pull request per cause, covering every variant, with a regression test. Reviewed and merged like any other PR.

Fix

1 PR · 3 variants fixed

Same root cause3 findings

Job ids trusted the request body

PR #4821 change

Reviewed and merged by your team

Every variantFixed

Regression test added

● One PR, every variant

04 · STAY FIXED

Stays fixed

Every branch and merge is re-attacked in CI against everything Feint has ever found. Export the proof for auditors and customers.

Stay fixed

2 regressions blocked

Re-attack addedPR #482

Runs on every merge

Merge #1,286Blocked

The IDOR came back

Claude Code agentBlocked

Same route, new branch

● Never ships twice

04 · STAY FIXED

Stays fixed

Every branch and merge is re-attacked in CI against everything Feint has ever found. Export the proof for auditors and customers.

Stay fixed

2 regressions blocked

Re-attack addedPR #482

Runs on every merge

Merge #1,286Blocked

The IDOR came back

Claude Code agentBlocked

Same route, new branch

● Never ships twice

Feint attacks an isolated copy of your environment the way a real adversary would. Only what actually works becomes a finding, and every finding ends in a merged fix.

CASE STUDIES

Real exploits

Feint found in production.

SEE ALL CASE STUDIES

Quilon · Read any customer’s invoices through an unscoped export job

A background export trusted the tenant id from the request body instead of the session. Feint chained it with a predictable job id and pulled 12 months of invoices from a test tenant.

export job

tenant id from body

guessable job id

12 months of invoices

BROKEN ACCESS CONTROL

Quilon · Read any customer’s invoices through an unscoped export job

A background export trusted the tenant id from the request body instead of the session. Feint chained it with a predictable job id and pulled 12 months of invoices from a test tenant.

export job

tenant id from body

guessable job id

12 months of invoices

Orbiq · Walked an AI copilot into another tenant’s CRM with one email

An indirect prompt injection hidden in a customer email drove the support agent to call a CRM tool with the wrong tenant id. Four turns, no human in the loop.

customer email

hidden prompt

crm.lookup(tenant=*)

another tenant’s CRM

PROMPT INJECTION · MCP

Orbiq · Walked an AI copilot into another tenant’s CRM with one email

An indirect prompt injection hidden in a customer email drove the support agent to call a CRM tool with the wrong tenant id. Four turns, no human in the loop.

customer email

hidden prompt

crm.lookup(tenant=*)

another tenant’s CRM

Vantrix · Signed in as admin with a JWT from the staging issuer

Production accepted tokens from both issuers after a migration. Staging signing keys had been in a public repo for six weeks.

staging issuer

leaked signing key

prod accepts token

admin session

AUTH BYPASS

Vantrix · Signed in as admin with a JWT from the staging issuer

Production accepted tokens from both issuers after a migration. Staging signing keys had been in a public repo for six weeks.

staging issuer

leaked signing key

prod accepts token

admin session

Fernway · Persisted a shell hook from inside a read-only CI sandbox

A poisoned lockfile convinced the build step to run a post-install script that wrote to the runner’s home directory, surviving the next job.

poisoned lockfile

post-install script

runner home dir

persists to next job

SANDBOX ESCAPE

Fernway · Persisted a shell hook from inside a read-only CI sandbox

A poisoned lockfile convinced the build step to run a post-install script that wrote to the runner’s home directory, surviving the next job.

poisoned lockfile

post-install script

runner home dir

persists to next job

SOLUTIONS

Built for the stack you actually run.

Whatever you ship, Feint comes with playbooks tuned to the attack paths that matter in your domain, across four surfaces: API, cloud, CI and AI agents.

All

FinTech

HealthTech

AI products

SaaS

Dev tools

Agents & MCP

PAYMENTS & FINTECH

IDOR on ledgers, race conditions on balance updates, KYC bypass, replay of signed webhooks.

LLM FEATURES

Prompt injection through user content, tool-call abuse, data leaking across tenants via retrieval.

MULTI-TENANT SAAS

Tenant isolation, role escalation, export jobs, invitation flows and SSO misconfiguration.

HEALTH DATA

PHI exposure through logs and exports, consent-scope bypass, FHIR endpoint enumeration.

AGENTS & MCP SERVERS

Tool poisoning, indirect prompt injection through tool output, over-permissioned tools and cross-tenant confused-deputy paths.

DEVELOPER PLATFORMS

CI sandbox escapes, token scope creep, supply-chain hooks and OAuth app abuse.

PAYMENTS & FINTECH

IDOR on ledgers, race conditions on balance updates, KYC bypass, replay of signed webhooks.

LLM FEATURES

Prompt injection through user content, tool-call abuse, data leaking across tenants via retrieval.

MULTI-TENANT SAAS

Tenant isolation, role escalation, export jobs, invitation flows and SSO misconfiguration.

HEALTH DATA

PHI exposure through logs and exports, consent-scope bypass, FHIR endpoint enumeration.

AGENTS & MCP SERVERS

Tool poisoning, indirect prompt injection through tool output, over-permissioned tools and cross-tenant confused-deputy paths.

DEVELOPER PLATFORMS

CI sandbox escapes, token scope creep, supply-chain hooks and OAuth app abuse.

BY THE NUMBERS

Feint, measured.

A manual pentest takes weeks, costs five figures, and is stale the day it ships. Feint covers more ground in hours and re-runs every time your code does.

ATTACK STRATEGIES

12,000+

Distinct techniques across access control, injection, auth, business logic and supply chain.

ATTACK STRATEGIES

12,000+

Distinct techniques across access control, injection, auth, business logic and supply chain.

TIME TO FIRST EXPLOIT

<1 hr

Feint

<1 hr

Pentest

3–6 wks

First exploitable finding typically within the hour of connecting a target.

TIME TO FIRST EXPLOIT

<1 hr

Feint

<1 hr

Pentest

3–6 wks

First exploitable finding typically within the hour of connecting a target.

NOISE REMOVED

95%

1 in 20 alerts reaches you, with proof

Of scanner alerts never reach your team, because Feint could not exploit them.

NOISE REMOVED

95%

1 in 20 alerts reaches you, with proof

Of scanner alerts never reach your team, because Feint could not exploit them.

CUSTOMERS

Three buyers. One answer.

CTOs buy the pull requests. CISOs buy the signal. Engineering leads buy the fact that it found what nothing else did.

41 min

“Our first pentest report was a pull request. The auditor had never seen that before.”

Priya Raman

CTO & co-founder, Quilon

95%

“We went from 1,200 findings a quarter to eleven. All eleven were real.”

Dana Whitfield

CISO, Vantrix

4 turns

“Every scanner said our LLM feature was fine. Feint read a customer email and walked out with another tenant’s data in four turns.”

Tyler Brooks

Head of Engineering, Orbiq

RESEARCH

From the lab behind Breakcost.

Feint is an AI security lab. Everything we ship is grounded in our own research on adversarial cost, multi-step attack discovery and the way real breaches chain small bugs into a takeover. The product is built on that research.

BENCHMARK

Breakcost

A benchmark that measures what an attacker spends, in tokens and hours, to reach a defined goal inside a real system. Across 40 production APIs the spread was a hundredfold. It turns security from pass or fail into a number a CFO and a CISO can both read.

Read the paper

BENCHMARK

Breakcost

Read the paper

OPEN SOURCE

Decoy

An open-source attack harness. Point it at your own staging, watch how a multi-step campaign is planned, and add your own attack strategies. Monthly challenges to break real agents, with the winning chains published.

Star on GitHub ★ 1,204

OPEN SOURCE

Decoy

Star on GitHub ★ 1,204

SECURITY & TRUST

Security your CISO can sign off on.

Pointing Feint at production adds almost nothing to your attack surface. Read-only by default, isolated per run, never trained on your data. The Feint MCP server cannot write until you approve a PR.

Request documents

SOC 2 Type II

IN PROGRESS

GDPR

DPA READY

HIPAA

BAA AVAILABLE

Never trained on your data

Isolated, ephemeral scan environments

Encrypted in transit (TLS 1.2+) and at rest (AES-256)

Least-privilege, logged access · SSO for enterprise

Read-only by default, write only when you approve a PR

Responsible-disclosure program and security.txt

Pricing that fits how you ship.

Pay per target, or run continuously in CI.

Yearly · save 20%

Monthly

TEAM

FREE TRIAL

For teams shipping to production.

$390

/mo

Billed yearly

Start free trial

5 targets

Attack every branch

Auto-fix pull requests

Feint MCP

Slack & Jira integrations

Email support

BUSINESS

$1,490

/mo

Billed yearly

Book a demo

Everything in Team

Unlimited targets

Continuous + scheduled attacks

Findings dashboard & export

Regression tracking

SSO · audit log · priority support

ENTERPRISE

Dedicated infrastructure for regulated teams.

Custom

Scoped to your environment

Talk to sales

Everything in Business

Dedicated infrastructure

Custom SLAs

SOC 2, HIPAA, ISO 27001, NIS2, DORA

Hands-on remediation support

Yearly · save 20%

Monthly

TEAM

FREE TRIAL

For teams shipping to production.

$390

/mo

Billed yearly

Start free trial

5 targets

Attack every branch

Auto-fix pull requests

Feint MCP

Slack & Jira integrations

Email support

BUSINESS

$1,490

/mo

Billed yearly

Book a demo

Everything in Team

Unlimited targets

Continuous + scheduled attacks

Findings dashboard & export

Regression tracking

SSO · audit log · priority support

ENTERPRISE

Dedicated infrastructure for regulated teams.

Custom

Scoped to your environment

Talk to sales

Everything in Business

Dedicated infrastructure

Custom SLAs

SOC 2, HIPAA, ISO 27001, NIS2, DORA

Hands-on remediation support

FAQ

Questions we get about

Feint.

Something else? security@feint.dev answers within a business day.

Does Feint need access to our source code?

No. Feint works black box against a URL. Connecting a repository is optional and only used to open fix pull requests. Read-only tokens are enough.

Will it break production?

How is this different from a scanner or an annual pentest?

Do you test our AI agents and MCP servers too?

Can we use the findings as SOC 2 or HIPAA evidence?

What happens after the trial?

FAQ

Questions we get about

Feint.

Something else? security@feint.dev answers within a business day.

Does Feint need access to our source code?

No. Feint works black box against a URL. Connecting a repository is optional and only used to open fix pull requests. Read-only tokens are enough.

Will it break production?

How is this different from a scanner or an annual pentest?

Do you test our AI agents and MCP servers too?

Can we use the findings as SOC 2 or HIPAA evidence?

What happens after the trial?

GET STARTED

Run your first attack on your own code.

Point Feint at staging. Within the hour you’ll have a proven finding, or a clean report you can show your auditor.

Start free trial

Book a demo

No credit card · First exploit within the hour

GET STARTED

Run your first attack on your own code.

Point Feint at staging. Within the hour you’ll have a proven finding, or a clean report you can show your auditor.

Start free trial

Book a demo

No credit card · First exploit within the hour

GET STARTED

Run your first attack on your own code.

Point Feint at staging. Within the hour you’ll have a proven finding, or a clean report you can show your auditor.

Start free trial

Book a demo

No credit card · First exploit within the hour

feint_

Autonomous offensive security for modern software.

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