---
title: 'Senior Backend / Platform Engineer at Causa Prima'
canonical: 'https://feeny.ai/job/senior-backend-platform-engineer-causa-prima-madrid-q3bcr2bmcw7y'
type: 'job'
last_seen: '2026-09-05'
---

# Senior Backend / Platform Engineer at Causa Prima

- **Company:** Causa Prima
- **Location:** Madrid, Spain
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-05-04
- **Last confirmed live:** 2026-09-05
- **Apply:** https://jobs.ashbyhq.com/causaprima/b06399e5-b2df-4cb6-ad78-28a9fac7a6db/application

**Skills:** Python, TypeScript, PostgreSQL, Systems Design, Event Sourcing, Application Security Architecture, Encryption Models, Key Management, Auth Patterns, Policy-as-code, Cerbos, OPA, Cedar, Database Architecture, Schema Design, Performance Tuning, Digital Signatures, Hash Chaining, Application-layer Encryption, Event Streaming Platforms

> Design and build the event-driven platform for AI agents, focusing on PostgreSQL event storage, cryptographic signature infrastructure, and multi-tenancy. The role involves implementing authorization gateways, PII vaults, and secure database architecture to ensure reliability, audibility, and GDPR compliance.

## Job description

You'll own the platform our agents run on — event-driven architecture, data pipelines, integrations with customer accounting systems, and the infrastructure that makes everything reliable, auditable, and fast.

## What you'll do

- Event store — Append-only PostgreSQL with tamper-evident hash chaining, real-time event distribution, agent replay and recovery, schema versioning.
- Cryptographic signature infrastructure — Key management, signature verification on all agent events, approval chains for external actions.
- Workflow Constraint Engine — The gateway that verifies authorization before any external action (email, payment, API call) proceeds.
- PII Vault & GDPR compliance — Isolated, encrypted storage for personal data. Right to erasure. Data residency per region.
- Multi-tenancy — Row-level security, tenant isolation across all data stores, tenant-scoped LLM API keys.
- Authorization (Cerbos) — Attribute-based access control for agents and humans. Deterministic policy evaluation — LLMs never make auth decisions.
- MCP security layer — Authentication, capability-based scoping per partner, and rate limiting for the Model Context Protocol endpoint.
- Database architecture — PostgreSQL schema design, indexing strategy, performance tuning, read replica topology.

## What we're looking for

- 3+ years experience with Python and/or TypeScript in production.
- 5+ years designing backend platforms for production systems.
- Strong systems design skills — this is the primary requirement. You think in boundaries, contracts, failure modes, and scaling characteristics.
- Deep PostgreSQL knowledge — RLS, indexing tradeoffs, event sourcing patterns, schema evolution.
- Strong application security architecture skills: encryption models, key management, auth patterns.
- Experience with policy-as-code authorization (Cerbos, OPA, Cedar, or similar).
- Strong code review skills for security-sensitive AI-generated code.
- Nice to have:
- Cryptographic primitives in production (digital signatures, hash chaining, application-layer encryption).
- Event streaming platforms (Kurrent, Redpanda, Kafka).
- SOC 2 or GDPR compliance engineering.
- Fintech or regulated-environment background.

## About Causa Prima

## Company Overview
- **One-liner**: Causa Prima operates an agent-to-agent network that automates invoicing, dispute resolution, and payment-term negotiations between buyers and suppliers for finance teams.
- **Entity Type**: Private (Pre-Seed)
- **Headquarters**: Madrid, Spain & Munich, Germany
- **Founded**: 2025 (implied by recent funding and hiring activity in early 2026)
- **Founders**: Maex Ament (CEO), Henrik Gebbing (COO), Philip Stanislaus (CTO)

## Core Business
- **Primary industry**: B2B Fintech / Accounts Payable & Receivable Automation
- **Target customers**: SMB and Enterprise finance teams (buyers and suppliers)
- **Mission or purpose**: To eliminate fixed payment terms (Net-30, Net-60) by enabling AI agents on both sides of a transaction to settle instantly, so money moves on the right terms at the right time automatically.

## Products & Services
- **Causa Prima Network**: A two-sided agent-to-agent network where AI agents handle invoicing, dispute resolution, and dynamic discounting. Buyers and suppliers connect on one platform, removing manual handoffs between AP and AR systems.
- **Scribo (Open Source)**: A free, AI-native e-invoicing tool compliant with EN 16931 (ZUGFeRD/XRechnung for Germany, US plain PDF). Available as an MCP server, Claude/Codex skill, CLI, HTTP API, and web app. Designed to help developers and finance teams generate compliant invoices programmatically.

## Market Standing
- **Valuation/Market Cap**: Not disclosed (pre-seed stage)
- **Key Metric**: $10M in total funding (pre-seed round, announced June 2026)
- **Notable Investors/Partners**: Creandum (led the round), Kfund, HelloWorld, Angel Invest, plus angel investors from Qonto, Pennylane, SAP, ING, SoFi, LIDL, and DeepMind.
- **Growth Signals**: Already trusted by 3,000+ accounts; headcount grew 28.6% monthly (LinkedIn data as of mid-2026); hiring for engineering and product roles in Madrid and Munich; open-source Scribo project gaining traction (12 stars on GitHub).

## Competitive Advantages
- **Two-sided network**: Unlike competitors that automate only one side (AP or AR), Causa Prima connects both buyers and suppliers on a shared network, eliminating the gap between systems.
- **Founder credibility**: Maex Ament invented dynamic discounting and co-founded Taulia (acquired by SAP, processing $50B/quarter). Henrik Gebbing built Finoa to $10B in assets under custody. Philip Stanislaus led 600+ enterprise security audits at Oak Security.
- **Agent-native design**: The platform is built from the ground up for AI agents to negotiate in real time, not just to speed up human workflows.

## Strategic Focus
- **Current priorities**: Grow the engineering and product teams in Madrid and Munich; scale the network beyond 3,000 accounts; push toward eliminating fixed payment terms entirely by making agent-to-agent settlement the default.
- **Direction**: Move from automating existing finance processes to replacing the underlying paradigm of B2B payments (Net-30/60/90) with instant, AI-driven settlement.

## Why Work Here
- **Culture**: Described by founders as a “once-in-a-lifetime opportunity” for people who want to build high-impact infrastructure from scratch. Emphasis on entrepreneurial drive and solving a problem that software has never fully addressed.
- **Remote/Hybrid/Office**: Presence in Madrid and Munich; roles appear to be in-office or hybrid (engineering roles listed in these cities).
- **Notable perks/engineering culture**: Early-stage startup with a small team (6 employees as of mid-2026) — high ownership and direct impact. Tech stack includes TypeScript, GraphQL, PostgreSQL, Redis, Terraform, Kubernetes, and Python. Open-source contributions (Scribo) are a core part of the product strategy. Backed by top-tier VC (Creandum) with strong founder track record.

## Sources
1. [causaprima.ai](https://causaprima.ai/)
2. [jobs.ashbyhq.com](https://jobs.ashbyhq.com/causaprima)
3. [linkedin.com](https://www.linkedin.com/company/causa-prima)
4. [github.com](https://github.com/causa-prima-ai)
5. [techfundingnews.com](https://techfundingnews.com/causa-prima-10m-pre-seed-creandum-b2b-payments-ai-agents-network/)

## Other roles at Causa Prima

- [Founders' Associate](https://feeny.ai/job/founders-associate-causa-prima-madrid-4v0bbe0gr36x) — Madrid, Spain
- [Marketing Lead](https://feeny.ai/job/marketing-lead-causa-prima-madrid-7pvpq4xs2c3f) — Madrid, Spain
- [Platform Security Engineer](https://feeny.ai/job/platform-security-engineer-causa-prima-madrid-6esyzfz8h6qj) — Madrid, Spain
- [Open Application](https://feeny.ai/job/open-application-causa-prima-madrid-5fx837v9ker4) — Madrid, Spain