LegacyMock

Cloud simulators for legacy banking APIs – test integrations without the mainframe.

Score: 7.2/10RWMedium BuildReady to Spawn
Brand Colors

The Opportunity

Problem

Enterprise fintech teams struggle to integrate modern APIs into legacy banking systems, causing significant delays in product rollouts.

Solution

LegacyMock creates instant, accurate mock servers mimicking legacy banking endpoints based on protocol docs or traffic captures. Fintech teams spin up isolated sandboxes for parallel dev/testing, catching issues pre-prod without risking legacy systems. Export mocks to CI/CD for automated regression testing.

Target Audience

Enterprise fintech teams building or updating banking products

Differentiator

Protocol-aware mocks with stateful sessions, not generic API mockers.

Brand Voice

supportive

Features

Protocol Importer

must-have15h

Import legacy specs (ISO 8583, FIX) or HAR files to build mocks.

Mock Server Creator

must-have25h

Generate and launch stateful mock endpoints instantly.

Scenario Builder

must-have18h

Define response scenarios, delays, and error injections.

Test Runner

must-have12h

Integrated UI to run API tests against mocks.

Traffic Recorder

must-have20h

Proxy real traffic to learn and refine mocks.

CI/CD Export

nice-to-have10h

Export mock as Docker image for pipelines.

Shared Sandboxes

nice-to-have8h

Collaborate on mocks with team access.

Performance Replay

future6h

Replay captured traffic for load testing.

Total Build Time: 114 hours

Database Schema

users

ColumnTypeNullable
iduuidNo
emailtextNo

Relationships:

  • one-to-many with projects

projects

ColumnTypeNullable
iduuidNo
user_iduuidNo
nametextNo

Relationships:

  • foreign key to users.id, one-to-many with mocks

mocks

ColumnTypeNullable
iduuidNo
project_iduuidNo
endpointtextNo
scenarios_jsontextNo
activeboolNo

Relationships:

  • foreign key to projects.id

test_runs

ColumnTypeNullable
iduuidNo
mock_iduuidNo
results_jsontextNo
timestamptimestampNo

Relationships:

  • foreign key to mocks.id

API Endpoints

POST
/api/projects

Create project

🔒 Auth Required
POST
/api/mocks

Create mock from import

🔒 Auth Required
POST
/api/mocks/:id/run-test

Execute test suite

🔒 Auth Required
GET
/api/test-runs/:mockId

List test results

🔒 Auth Required

Tech Stack

Frontend
Next.js 14 + Tailwind + shadcn/ui
Backend
Next.js API routes
Database
Supabase Postgres
Auth
Supabase Auth
Payments
Stripe
Hosting
Vercel
Additional Tools
WireMock libResend

Build Timeline

Week 1: Auth and project mgmt

35h
  • Signup
  • Projects CRUD

Week 2: Importer and mock gen

45h
  • Spec parser
  • Basic mock server

Week 3: Scenario editor

40h
  • UI builder
  • Stateful logic

Week 4: Testing tools

35h
  • Test runner
  • Recorder

Week 5: Exports and collab

30h
  • CI export
  • Sharing

Week 6: Launch prep

25h
  • Payments
  • LP

Week 7: Polish

20h
  • Bug fixes
  • Docs
Total Timeline: 7 weeks • 230 hours

Pricing Tiers

Free

$0/mo

1k req/mo

  • 3 projects
  • Basic mocks

Pro

$30/mo

50k req/mo

  • Unlimited projects
  • Advanced scenarios
  • Team share

Enterprise

$99/mo

None

  • All Pro + Custom protocols
  • Unlimited

Revenue Projections

MonthUsersConversionMRRARR
Month 1603%$54$648
Month 62507%$525$6,300

Unit Economics

$35
CAC
$300
LTV
6%
Churn
90%
Margin
LTV:CAC Ratio: 8.6xExcellent!

Landing Page Copy

Mock Legacy Banking APIs Safely

Accelerate dev cycles with accurate, cloud-based simulators.

Feature Highlights

Protocol importers
Stateful scenarios
Built-in testing
Traffic recording
CI/CD ready

Social Proof (Placeholders)

"'Perfect for our mainframe tests!' - Dev @FinCorp"
"'Cut testing time in half.' - Engineer @PayTech"

First Three Customers

Share demo video on Twitter/X fintech threads; Join Discord communities for banking devs; Run $100 LinkedIn ads targeting 'fintech integration' keywords.

Launch Channels

Product Huntr/SaaSTwitterIndie Hackers

SEO Keywords

legacy api mockbanking api simulatoriso 8583 mock serverfintech testing sandboxmainframe api tester

Competitive Analysis

WireMock Cloud

wiremock.io
$25+/mo
Strength

General mocking

Weakness

No banking protocols

Our Advantage

Fintech-specific with state

🏰 Moat Strategy

Growing library of user-submitted protocol mocks creating network effects.

⏰ Why Now?

DevOps shift in fintech demands fast testing amid talent shortages.

Risks & Mitigation

technicalmedium severity

Mock fidelity

Mitigation

User feedback loops

executionlow severity

Build delays

Mitigation

Modular dev

financialmedium severity

Low conversions

Mitigation

Freemium ramps

Validation Roadmap

pre-build5 days

Survey 15 devs on pains

Success: 80% interest

mvp35 days

Beta with 10 users

Success: 3 paying

growth30 days

Content marketing

Success: 100 users

Pivot Options

  • Pure traffic proxy
  • Full test suite tool
  • General protocol lib

Quick Stats

Build Time
230h
Target MRR (6 mo)
$1,500
Market Size
$2000.0M
Features
8
Database Tables
4
API Endpoints
4
LegacyMock - Complete Startup Blueprint | Startup Tribunal | StartupTribunal