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Rex launch: what they're building and where to launch next

FoxPlug writes launch posts from what a startup ships and matches it to the launch communities that fit it. This page shows what Rex is building and where it could launch next; if it is your startup, start free below.

What they're building

AI-native BPO for enterprise order-to-cash

Batch
Y Combinator Summer 2026
Industry
B2B
Team size
2
Based
San Francisco, CA, USA

Founders

rex.inc ↗

See their funding details ↗

Rex on the record

What they shipped

  • From its YC profile: Rex is an AI-native service for order to cash. Rex replace manual operations with AI agents that continuously manage invoices, customers and exceptions. Order to cash is a $60B outsourced function because the work is too messy for traditional automation. Every customer has different context, exceptions do not follow clean rules, and the next step is often buried in emails, portals, handoffs, or someone’s memory. Rex agents run continuously in the background and resolve work to SLA standards so cash keeps moving. (source)
  • Its own site describes it as: "Rex is the AI operations partner for order-to-cash. Its agents cover every account and resolve exceptions before cash gets stuck." (source)

Who is behind it

  • Merlin Kafka, Founder/CEO: Merlin is the Founder and CEO of Rex, the AI partner for enterprise order-to-cash. He spent 4 years as CPO at Sequence (a16z-backed), an order-to-cash platform where he grew the company to millions in ARR and hundreds of customers. He has deep domain expertise in order to cash and accounts receivable workflows -- the exact space Rex is transforming with AI. (source)
  • Lewis Blackwood, Founder/CTO: Founder and CTO at Rex, building the AI partner for enterprise order to cash. Previously: - Founding engineer at Sequence (backed by a16z) - Cofounded Personably (backed by Global Founders Capital) - Early team at GoCardless (YC S11) - Economics at Cambridge (source)

Timeline

  1. 2026: founded, per its YC profile. (source)

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Where else to launch Rex

  • Product Hunt ↗
    Self-promotion allowedFree
  • Indie Hackers Forum ↗
    Self-promotion allowed
    Audience: IndieHackers; bootstrapped solo founders sharing revenue and behind-the-scenes
  • Hacker News (Show HN) ↗
    Self-promotion allowed, within the community's rules
    Audience: Hacker News readers; engineers, technical founders, infra-curious people
  • Demand Curve ↗
    Self-promotion allowed, within the community's rules
    Audience: Slack community; tight-knit, pseudo-private peer group
  • No Code Founders ↗
    Self-promotion allowed, within the community's rules
    Audience: Slack community; tight-knit, pseudo-private peer group
  • OnlineGeniuses ↗
    Self-promotion allowed, within the community's rules
    Audience: Slack community; tight-knit, pseudo-private peer group
  • Product Makers ↗
    Self-promotion allowed, within the community's rules
    Audience: Slack community; tight-knit, pseudo-private peer group
  • ProductLed ↗
    Self-promotion allowed, within the community's rules
    Audience: Slack community; tight-knit, pseudo-private peer group

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