Rex replaces manual invoice chasing and cash-matching for finance teams already running NetSuite, SAP, or Salesforce, not solo bookkeepers or businesses without a formal ERP. It reportedly frees accounts receivable operators about 15 hours a week to focus on the exceptions a human still has to review.
Rex is an AI agent platform for enterprise accounts receivable teams that automates invoice follow-ups, dispute routing, and cash reconciliation. Early enterprise deployments report a 12-day reduction in days sales outstanding. Unlike a single support chatbot, Rex runs continuous, semi-autonomous agents across every customer account and connects directly to NetSuite, SAP, and Salesforce without a data migration.
Maker: Rex Inc. · Autonomy: semi autonomous · Maturity: BETA
About Rex
Rex is an agentic AI platform built by Rex Inc. for enterprise finance teams that automates order-to-cash work such as invoice follow-ups, collections, dispute resolution, and cash reconciliation. Founders Merlin Kafka and Lewis Blackwood previously built the a16z-backed finance platform Sequence, and designed Rex to connect directly into a company's existing ERP and inbox rather than requiring a system migration.
Rex runs a network of specialized agents instead of a single chatbot: each one triages inbound emails and portal messages, follows up on overdue invoices, uploads documents to supplier and customer portals, and reconciles incoming cash against open invoices around the clock. Routine work runs end to end without a human in the loop; anything outside standard policy escalates to a person instead, which is what separates Rex from a support chatbot that only responds to prompts.
Rex is built for finance and accounts receivable teams at mid-size to large enterprises that already run their receivables through NetSuite, SAP, Salesforce, or similar systems. Reported customers span roughly $500 million in receivables under management across their accounts. It is a poor fit for very small businesses or teams without a formal ERP already in place.
Rex is an early-stage company, part of Y Combinator's Summer 2026 batch. With a small founding team as of mid-2026, it is still building out its integration list and has not published a public changelog, so expect the product and its guardrails to change as it scales beyond its first enterprise customers.
Pricing
Custom, enterprise, sales-led pricing only. No public tiers or list price. Company describes a 'no results, no fee' outcome-based model targeting companies with $100M-$1B in annual revenue. No self-serve signup or free trial.
Key Features
- Autonomous Collections Follow-Up: Runs invoice and payment follow-ups across every customer account continuously, without a person triggering each individual message.
- Cash Reconciliation: Matches incoming payments against open invoices and clears cash automatically, without a human reconciling line items by hand.
- Inbox and Portal Triage: Reads incoming emails and portal messages and routes each one to the right workflow in about a minute on average.
- Dispute and Exception Routing: Escalates VIP accounts, disputes, and policy exceptions to a human with full context and supporting evidence attached.
- No-Migration ERP Integration: Connects directly into NetSuite, SAP, and Salesforce plus existing inboxes without requiring a system migration project.
- Live Activity Dashboard: Surfaces daily SLA, blocked-cash, and exception summaries, as seen on one customer dashboard tracking $18.4 million in receivables.
Strengths
- Reports a real reduction in days sales outstanding rather than a generic productivity claim, the outcome AR leaders are actually measured on.
- Skips the ERP migration project that usually stalls AR software rollouts, since it plugs directly into NetSuite, SAP, and Salesforce as they already exist.
- Won the Vercel AI Accelerator Demo Day out of roughly 2,500 competing teams, judged by leaders from Vercel, OpenAI, Anthropic, AWS, and Browserbase.
Weaknesses
- Pricing is entirely custom and sales-led, with no public tiers or free trial for smaller finance teams to test.
- Best fit is companies with $100 million to $1 billion in annual revenue running a formal ERP, so it is a poor match for small businesses.
- The company has not disclosed which underlying language model powers its agents, limiting independent technical evaluation.
- Founding team was listed at just two people as of its 2026 YC batch, which raises questions about support capacity at enterprise scale.
Frequently Asked Questions
What are Rex's pricing plans in 2026?
Rex does not publish list pricing or self-serve plans. It sells custom, enterprise contracts through a sales-led process built around a 'no results, no fee' outcome-based model. Pricing is scoped to a company's receivables volume and account count, and prospective customers book a demo through the Rex website to get a quote.
Can you use Rex without paying?
No. Rex has no free tier and no self-serve signup; every plan runs through a custom sales-led contract. A smaller finance team that wants to test the product informally before committing has to go through a paid demo and scoping process instead.
What are the best alternatives to Rex?
Kolleno is a close alternative built as an order-to-cash platform with its own AI agents, and it publishes more public case studies than Rex does. HighRadius is a larger, longer-established player in AI-driven accounts receivable, suited to companies that want a mature product with broader analytics. Tesorio leans more toward cash forecasting than collections execution, so it fits teams that weight forecasting accuracy over automated follow-ups.
Rex or Kolleno: which should you pick?
Rex's pitch is a no-migration integration path: it plugs into NetSuite, SAP, or Salesforce as they already exist, while Kolleno is positioned as a broader order-to-cash platform with more published case studies to evaluate before buying. Neither vendor publishes a self-serve price list, so a team wanting a documented quote up front may find Kolleno's public materials easier to evaluate against. Pick Rex if the no-migration approach and outcome-based pricing model matter more than vendor track record.
How long does it take to get going with Rex?
Getting started means booking a demo through the Rex website, since there is no self-serve signup or free trial. During that process the Rex team reviews your existing ERP setup and receivables volume to scope a custom contract, then connects its agents to your systems and inboxes without a data migration. Expect an initial period where Rex's agents run alongside your existing collections process while accuracy and guardrails are validated on real accounts.