Open Source · Free to Use

Fintech Tools for Payments Professionals

The payments industry runs on opaque systems, proprietary tooling, and institutional knowledge locked behind consulting fees. We built this suite to change that — twenty-seven free, open-source tools covering the full A2A payments stack, from ISO 20022 message construction to fraud scoring to compliance checklists. Every tool runs entirely in your browser. No accounts, no subscriptions, no data leaving your device.

33 Tools available

0 Data transmitted

5 Rail families covered

CC BY 4.0 licensed

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Privacy by design. Every tool on this page runs 100% client-side — all logic executes in your browser, nothing is sent to our servers. No PII, no account numbers, no transaction data is collected or transmitted at any point.

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All tools are now hosted at AINumbers.co

Post Oak Labs designed and built this suite. Each card below opens the live tool at AINumbers.co — our dedicated fintech tooling platform.

Visit AINumbers.co ↗

Post Oak Labs · New — Q2 2026

Agentic Intelligence Suite Beta

Six AI-powered tools for tokenized A2A infrastructure — built on deterministic reasoning engines, not open-ended LLMs. Privacy-first, zero network transit, single-file delivery. Designed for treasury teams, compliance officers, and payment engineers operating on tokenized rails, stablecoin corridors, and CBDC frameworks in emerging markets.

6AI tools

0External calls

AP2Compatible export

✓ Zero Network Transit ✓ Zero PII Deterministic Engines Agentic Export AP2-Compatible JSON

SMB Treasury Tax Assistant

Privacy-first cross-border tax planning for SMBs on tokenized A2A rails. Estimates liability, identifies deductions, and generates audit-ready strategy reports across five jurisdictions — US, EU, Brazil, Nigeria, and Mexico — using a deterministic JS calculator and embedded knowledge base.

Client-Side Zero PII JSON + MD AI-Powered

A2A Exception Triage Console

Deterministic agentic reasoning for payment failures on FedNow, RTP, SEPA Instant, PIX, and tokenized rails. Diagnoses ISO 20022 and NACHA error codes via a ReAct trace loop, generates recovery workflows, and exports agentic prompts for LangChain, AutoGen, and CrewAI.

Client-Side Zero PII ReAct Loop

Tokenized M&A Due Diligence Lens

Client-side clause extraction for cross-border acquisition documents in emerging markets. Drag-and-drop SPAs, regulatory filings, and tokenized-asset contracts — a rule-based NLP pipeline extracts parties, dates, amounts, clauses, and compliance flags locally. Zero data leaves the browser.

Client-Side Zero PII JSON + CSV AI-Powered

Agent Policy Guardrail Builder

Define, simulate, and export machine-readable mandates for AI agents on A2A rails. Transforms institutional payment policies into agent-safe runbooks, approval workflows, and hard guardrails — with an inline SVG DAG visualiser. Critical for governance before autonomous agents transact.

Client-Side Zero PII JSON + MD AI-Powered

Regulatory Doc Intelligence

Extract compliance clauses from CBDC guidelines, PSD3 drafts, MiCA, SAMA, CBUAE, and FinCEN frameworks — entirely in-browser. Configurable extraction rules, framework coverage analysis across eight compliance domains, and a Privacy Audit button to verify zero-transmission.

Client-Side Zero PII JSON + MD AI-Powered

Agentic Mandate Sandbox

Simulate and export agent payment policies for tokenized A2A corridors. Configure spend caps, MCC allowlists, velocity throttles, approval thresholds, and time windows — then test against synthetic transactions across five distribution modes (uniform, skew-high, clustered, adversarial) before real money moves. Exports AP2-compatible mandate JSON for direct ingestion by MCP and agent runtimes.

Client-Side Zero PII AP2 JSON Agentic

These tools are designed for payments engineers, ops teams, treasury analysts, and compliance professionals who need hands-on prototyping, validation, and reference tooling without standing up infrastructure. Use them to validate concepts, onboard new team members, generate artifacts for stakeholder presentations, or simply understand how the rails work under the hood. All tools are open source under CC BY 4.0 — fork, adapt, and embed freely with attribution. The six Agentic Intelligence Suite tools are pinned at the top — deterministic agentic engines for tokenized A2A corridors, stablecoin infrastructure, and CBDC frameworks in emerging markets.

33 tools · Q2 2026

Category 01

Core Infrastructure

5 tools

A2A Fee Calculator + Route Optimizer

Compare the true all-in cost of card vs. A2A rails and get a transparent rule-based recommendation for the optimal payment route — FedNow, RTP, Same-Day ACH, or Next-Day ACH — based on amount, urgency, and network availability.

Client-Side Zero PII Export

ISO 20022 Builder + Pilot Brief Generator

Hand-craft valid ISO 20022 pain.001.001.12 XML payment messages field-by-field, with live validation and schema-aware guidance. Exports a formatted XML message and an executive pilot brief with readiness checklist.

Client-Side ISO 20022 Export

A2A Reconciliation Workbench + Reference Generator

Auto-match uploaded bank statements to ledger entries and reconcile exceptions. Generates ISO 20022 End-to-End IDs, NACHA Individual IDs, and SEPA CRF references. Handles duplicate detection, partial matches, and unmatched items.

Client-Side Zero PII ISO 20022

A2A Fee Benchmarking Report Builder

Input your current payment volume and cost structure, and generate a print-ready one-page executive report comparing your costs against A2A alternatives — FedNow, RTP, Same-Day ACH, and Next-Day ACH — with ROI projections.

Client-Side Export PDF

Synthetic A2A Test Data Generator

Generate up to 10,000 realistic synthetic A2A payment records with deterministic seed control — realistic transaction IDs, routing numbers, timestamps, return codes, configurable failure patterns, and duplicate injection. Export as CSV or JSON for pipeline testing, QA, and demo environments.

Client-Side Zero PII CSV + JSON

Category 02

Compliance & Consent

5 tools

Consent Simulator + Compliance Auditor

Prototype OAuth 2.0/PKCE consent flows step by step and audit your requested scopes against PSD2, CFPB 1033, and GDPR requirements. Flags over-permissioning, missing mandatory disclosures, and consent expiry mismatches.

Client-Side Zero PII

ACH / NACHA File Validator + Return Code Decoder

Drag-and-drop ACH/NACHA flat files for structural validation — header records, batch headers, entry details, addenda, and control records. Integrated R01–R85 return code decoder with plain-English explanations and retry guidance.

Client-Side Zero PII

VRP Mandate Builder + SEPA Validator

Draft UK Commercial VRP mandates with configurable parameters and validate SEPA credit transfers client-side. Includes MOD-97 IBAN check, BIC structural validation, SCT Inst limit enforcement, and pain.001 XML snippet generation.

Client-Side Zero PII ISO 20022

Instant Payment Limits Reference + Rail Comparator

Searchable, filterable reference for transaction limits, cut-off times, availability, and regulatory rules across FedNow, RTP, ACH, Faster Payments, SEPA Instant, PIX, UPI, PayID, and Zengin. Compare any combination of rails side-by-side.

Client-Side CSV Export

A2A Compliance Checklist Generator

Generate jurisdiction-specific compliance checklists for A2A product launches. Configure by market (US, UK, EU, Brazil, India, Australia) and product type, and receive a structured checklist covering licensing, AML/KYC, data privacy, consumer protection, error resolution, and fraud monitoring requirements.

Client-Side Zero PII Export

Category 03

Fraud & Risk

1 tool

Fraud Score Simulator + Explainability Panel

Demonstrate real-time A2A fraud scoring using a fully transparent, configurable rule-based engine — no black-box ML. Adjust transaction signals (amount, velocity, account age, device, geo) via sliders and toggles, and see each rule's point contribution explained in plain English. Supports configurable rule weights and an exportable risk report.

Client-Side Zero PII Rule-Based AI

Category 04

Payment Operations

5 tools

Invoice-to-A2A Tooling Suite

Parse invoice data into Pay-by-Bank deep links and QR codes, then reconcile incoming A2A payments back against those invoices. Covers FedNow, RTP, and Open Banking payment initiation link formats.

Client-Side Zero PII

FedNow Participant Lookup + Coverage Stats

Search FedNow-participating financial institutions by name, routing number, state, or send/receive capability. View coverage stats by state, institution type, and capability. Exportable to CSV for due diligence and network analysis.

Client-Side CSV Export

Pay-by-Bank Checkout Prototyper + Conversion Insights

Prototype a complete merchant Pay-by-Bank checkout flow across five interactive screens. Overlay conversion friction analysis at each step — bank selection, authentication, confirmation — and share your prototype via URL for stakeholder review.

Client-Side Zero PII

Payment Journey Mapper + Failure Points Overlay

Visualize end-to-end payment flows for FedNow, ACH, UK Open Banking, and SEPA Instant — from origination through clearing, settlement, and confirmation. Toggle a failure-points overlay to expose common failure modes and mitigation strategies at each step.

Client-Side Zero PII

Real-Time Ops Dashboard Template

A fully configurable mock real-time A2A payments operations dashboard. Monitor simulated FedNow, RTP, ACH, and SEPA Instant SLAs, latency percentiles, transactions per minute, and failure rates — all with configurable thresholds and alert states. Use as a template for internal ops tooling design and stakeholder demos.

Client-Side Zero PII Simulated Live

Category 05

Open Banking & APIs

2 tools

Open Banking API Explorer + Rate Limit Simulator

Browse and edit mock Open Banking and CFPB 1033 API responses across 10 endpoint types. Compare UK Open Banking v3.1 vs. CFPB 1033/FDX schemas side-by-side. Simulate 429 rate limit throttling with configurable profiles and generate retry code in JavaScript or Python.

Client-Side Zero PII Code Export

IBAN Validator + BIC Lookup + SEPA Reachability

Validate IBANs using the full MOD-97 algorithm with country-specific length checks, parse out the bank code and branch code, check BIC structural validity, and verify SEPA reachability for the counterparty institution. Batch mode for CSV validation.

Client-Side Zero PII

Category 06

Treasury, Strategy & Revenue

9 tools

Nostro/Vostro A2A ROI Memo Generator

Generate a ready-to-paste executive memo quantifying working capital savings of migrating from correspondent banking to tokenized A2A rails. Input volume, settlement days, and CB fee to receive a formatted memo with trapped capital estimate, fee savings projection, and a phased pilot recommendation.

Client-Side Zero PII Copy-Ready

A2A Payment Failure Analyser + RCA Generator

Paste a list of NACHA return codes or open banking error codes and receive a structured root-cause analysis report — failure clustering by category (NSF, account issues, authorisation, technical), trend identification, and a prioritised remediation plan. Client-side rule-based logic, zero PII.

Client-Side Zero PII Rule-Based AI

Emerging Market A2A Corridor Cheat Sheet

Instant-access structured reference for 30+ emerging market payment corridors — covering rail availability, FX volatility tiers, regulatory risk ratings, typical settlement times, and recommended A2A approach. Filter by region, risk tier, or rail type. Export as CSV.

Client-Side Zero PII CSV Export

Payment Decline Code Decoder & Recovery Guide

Look up any card or A2A payment decline code across Visa, Mastercard, NACHA, SEPA, and FedNow. Each entry includes the plain-English reason, whether to retry, recommended recovery action, and whether the issue is issuer-side, network-side, or originator-side.

Client-Side Zero PII

Cross-Border Corridor Savings Calculator

Calculate real cost savings of switching from SWIFT correspondent banking to A2A direct rails for a specific cross-border corridor. Enter send volume, current SWIFT fees, and FX spread to receive a projected annual saving, cost-per-transaction comparison, and illustrative payback timeline.

Client-Side Zero PII Copy-Ready

Subscription Churn Analyzer: Card vs. A2A/VRP

Quantify the ROI of migrating subscription payments from card-on-file to A2A / Variable Recurring Payments. Input subscriber count, ARPU, churn profile, and card failure rate assumptions to receive a plain-text ROI summary with recovered revenue projection and payback period.

Client-Side Zero PII Copy-Ready

ISO 20022 Payment Reference Generator

Generate valid, structured ISO 20022 End-to-End IDs, UETR (Unique End-to-End Transaction Reference) UUIDs, NACHA Individual IDs, SEPA CRF references, and FedNow trace numbers — in bulk, with configurable prefixes, date embedding, and batch export.

Client-Side Zero PII ISO 20022 CSV Export

CBDC / Stablecoin Treasury Sandbox

Simulate wholesale CBDC and stablecoin treasury flows — mint, burn, transfer, and redemption cycles — against configurable reserve ratios and liquidity rules. Prototype programmable payment logic and view real-time ledger state without connecting to any live network.

Client-Side Zero PII

A2A Settlement Finality Comparator

Compare settlement finality rules, irrevocability windows, and dispute timelines across FedNow, RTP, ACH, SEPA Instant, Faster Payments, PIX, and UPI. Understand when a credit becomes final, legally irrevocable, and when reversal is no longer possible — critical for treasury reconciliation design.

Client-Side Zero PII CSV Export

Suite complete

All 33 tools in the Post Oak Labs suite are now live — 27 open-source fintech tools plus six AI Suite tools built for tokenized A2A infrastructure. Each tool is open source under CC BY 4.0 — fork, adapt, and embed freely with attribution. All tools are listed in the sitemap. Follow @postoaklabs for future updates and new releases.