About the role

Quick facts

We're a global e-invoicing platform operating in 30+ countries
Revenue grew 10x last year and is on track to triple again this year to €3M ARR
Role: first dedicated post-sales hire. Own customer implementations end-to-end and build the post-sales function from scratch alongside the founders and engineering team
Looking for: 2+ years of experience in technical, customer-facing, or implementation roles. Strong coding fundamentals, clear communication, and high ownership
Compensation: €50-70k + ESOP
Based in Madrid, working in person from our office in Madrid

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Over the last few years, we've built a product customers genuinely love. More than 200 companies have implemented Invopop using only our API docs and support channels.

As we move upmarket, larger enterprises need more hands-on technical support to design, build, and launch their integrations successfully. That's why I'm looking for a Founding Solutions Engineer to help us build the post-sales function from scratch.

You'll work directly with engineering teams at some of the world's fastest-moving tech companies to get them live across multiple countries. You'll debug integrations, answer hard technical questions, design rollout plans, and help customers move from signed contract to production launch.

You should be technical enough to read logs, reason about integration architecture, and write quick scripts when needed - but also pragmatic, organized, and comfortable working directly with customers.

You'll report directly to me initially and, over time, help shape how implementations and technical onboarding work at Invopop.

What you'll do

Your mission as Founding Solutions Engineer

Your job is simple: help customers launch successfully with Invopop.

This includes:

Owning Enterprise customer onboarding from contract signature to production launch
Working directly with customer engineering teams to design and debug integrations
Help customers think through rollout plans and implementation approaches
Answer technical questions during the sales process alongside the commercial team
Improve API docs and build ERP connectors based on your learning
Build the playbook for implementations and technical onboarding

What we're looking for

Who we're looking for

Must-have:

2+ years of experience as software engineer or post-sales technical support
Excellent written and spoken English
Comfortable reading API docs, logs, HTTP requests, and JSON/XML payloads
Able to write code or scripts when needed
Strong communication, ownership, and structured thinking
Comfortable working directly with customers and driving projects forward

Nice to have

Familiarity with fintech, ERP, billing, tax, or compliance systems
Spanish

How you'll work

Where you'll work

We're in Madrid (Calle Guadalquivir, El Viso), 5 minutes from Nuevos Ministerios.

No fixed schedule. We expect at least 3 days/week in the office - high-context work moves faster in person. Sam and I are often in the office, and part of our role is to be close to decisions and context.

About the company & team

About Invopop

Invopop helps global companies like Qonto, Hyundai, and DeepL issue and receive invoices across more than 30 countries through a single API.

In the next five years, more than 40 countries, including the entire EU, will mandate that businesses send invoices electronically in XML format and report them in real time to tax authorities. This reduces fraud and enables companies to automate invoice processing instead of relying on OCR. There's only one catch: each country has defined unique standards, forcing global companies to build dozens of local integrations-or integrate once with Invopop. :)

Invopop was founded by Sam Lown, co-founder and former CTO of Cabify, and Juan Moliner (ex-BCG), based on Sam's experience dealing with this problem at Cabify

We've raised €2.8M from top-tier venture capital firms, including YCombinator (W23), and have been named the Best Startup at South Summit 2024 and Madrid's Hottest Startup of 2024 by Wired.

Hiring process

Interview process

The process has five steps:

Step 1: Screening call
Step 2: Intro call with Juan (30 min)
Step 3: Take-home exercise
Step 4: Deep-dive interview with Sam (1h)
Step 5: In-person interview with both founders (1h)

Additional information

Why join Invopop

World-class team: Work alongside experienced founders and builders, including Sam Lown, co-founder and former CTO of Cabify
A true founding role: Help define our post-sales function as we scale globally
Big upside and great setup: Competitive salary, meaningful ESOP, top equipment, flexibility, and a beautiful office in Madrid.

Founding Solutions Engineer

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