04 / CURRICULUM VITAE / SYSTEM ONLINE

FRITS
ZWAGER.

CUSTOMER SUCCESS · SALES · AI & AGENT TOOLS

Customer Success specialist with 4+ years of experience turning subscription customers into long-term revenue sources, combining consultative selling, sharp needs analysis and cross-functional collaboration. Next to that I build AI tools: four live services that AI agents find and pay for per call. Looking for a customer-facing role at a company that builds AI agents or voice AI: solutions, customer success or partnerships, in Amsterdam.

DOWNLOAD CV ↓ CONTACT ME ↗

LIVE · PAID PER CALL BY AI AGENTS

Tools for AI agents.

Four services I built and run. AI agents pay them per call in USDC, with no account and no API key, using the x402 standard.

FROM $0.01

presign-guard

A green, orange or red verdict before an agent or wallet signs a transaction, approval or signature.

OPEN ↗ FROM $0.001

x402 Doctor

Checks a paid API the way a paying agent would, with a fix for every problem. The web check is free.

OPEN ↗ FROM $0.02

Ichimoku Signal

Ichimoku Cloud trading signals, price levels and a ranked scan of 148 coins. The daily trend is free.

OPEN ↗ FROM $0.03

PlainText

presign-guard's verdict on a wallet's approvals, explained in plain language: who can move what, and whether to revoke it. 3 free checks a day.

OPEN ↗

TRY THEM LIVE ON FIZZL.EU →

01 / PROFILE

CUSTOMER
FIRST.
GROWTH
NEXT.

Customer Success specialist with 4+ years of experience in customer retention, account growth and consultative selling.

At Mediahuis, worked on proactive retention interventions, upsell/cross-sell opportunities and cross-functional escalation handling.

~20%CHURN
REDUCTION

200+B2C
ACCOUNTS

15–25%ACCOUNT
UPLIFT

02 / EXPERIENCE

2026 — PRESENT

AI BUILDER / INDEPENDENT

FIZZL

Designed, built and run four live pay-per-call services for AI agents, built with Claude and Claude Code: x402 Doctor (checks paid APIs before an agent pays), presign-guard (explains what a wallet signature can move), Ichimoku Signal (crypto trading signals) and PlainText (wallet approvals in plain language, built on presign-guard). Agents pay in USDC on Base or Solana via the x402 protocol; each service has an MCP server and is listed in the Coinbase Bazaar.

4 LIVE SERVICESPAID BY AI AGENTSMCP SERVERSx402 · BASE · SOLANACOINBASE BAZAAR

2024 — PRESENT

CUSTOMER SUCCESS / SALES

MEDIAHUIS

Customer Success & Sales Specialist managing a portfolio of 200+ B2C subscription customers of a news and media publisher. Focus on retention, account expansion, customer communication and cross-functional coordination.

~20% CHURN REDUCTION15–25% ACCOUNT UPLIFT30% FEWER ESCALATIONS< 4H RESPONSESALESFORCE

2020 — 2023

COMMERCIAL CONSULTING

STARTUPS & WEB3

Independent commercial consultant advising 6 early-stage startups on go-to-market strategy, SaaS propositions and founder pitch processes.

6 STARTUPS2 SaaS PROPOSITIONS50 USERS / 90 DAYS350K+ SEED FUNDING

2017 — 2019

SALES / OPERATIONS

TK MAXX AMSTERDAM

Sales and operations role focused on customer advice, product knowledge and supporting improvements to inventory processes.

TOP-3 SALES25-PERSON TEAM~15% FEWER STOCK ERRORS

03 / SKILLS

SALES

Consultative selling, upselling / cross-selling, churn reduction and account expansion.

CUSTOMER SUCCESS

Relationship management, needs analysis and customer retention. Salesforce CRM and Microsoft Office 365.

AI & AGENTS

Claude API and Claude Code, prompt design, RAG with automated evaluation, MCP servers and tools for AI agents, guardrails where the model explains but never decides.

BACKEND & APIs

Node.js / Express APIs, OpenAPI specs, scheduled jobs, caching, timeouts and fallbacks, rate limits and free quotas. Basic Python.

SECURITY & RELIABILITY

Secrets management, signed receipts for every verdict, timing-safe service-to-service auth, sanctions screening, health checks, monitoring and log-driven debugging.

WEB & TOOLING

Git and GitHub, GitHub Actions (tests, deploys, scheduled runs), Render, npm with trusted publishing, Playwright, HTML/CSS/JS and bilingual sites (NL/EN).

WEB3 & PAYMENTS

x402 payments in USDC on Base and Solana, ERC-20 approvals, EIP-712 and Permit2 signatures, wallet-security data (GoPlus, on-chain RPC).

DATA & RESEARCH

CRM-based account analysis, usage dashboards, backtests with random-entry controls and public paper tests with fixed rules.

LANGUAGES

Dutch native · English C1 · German B2 · French B1.

04 / EDUCATION

HIGHER EDUCATION

INHOLLAND

Small Business & Retail Management · Inholland Amsterdam

HIGHER EDUCATION

HVA

Media & Informatiemanagement · Hogeschool van Amsterdam

05 / PORTFOLIO

LIVE TOOLS FOR AI AGENTSFIZZL.EU/TOOLS ↗ AI / AUTOMATIONAI.FIZZL.EU ↗ PROJECTSPROJECTS.FIZZL.EU ↗ CODEGITHUB ↗

AI PROJECT

FIZZL DIGITAL TWIN

Grounded AI professional profile using Claude, semantic RAG, session memory and automated evaluation to make a CV conversational.

Live demo: ai.fizzl.eu ↗ · GitHub ↗

06 / CONTACT

LET'S TALK
ABOUT THE FUTURE.

FRITS.ZWAGER@GMAIL.COM ↗ LINKEDIN ↗

FRITSZWAGER.