# Rex

> Rex is the AI operations partner for order-to-cash. Its agents cover every account and resolve exceptions before cash gets stuck.

Full company brief: https://www.rex.inc/llms.md

## Resources

Category indexes. Fetch a category URL with `Accept: text/markdown` for the individual guides.
- [Comparisons & Alternatives](https://www.rex.inc/resources/comparisons): Honest comparisons of approaches, tools, and operating models for running back-office finance.
- [Guides & Playbooks](https://www.rex.inc/resources/guides): Step-by-step playbooks for running and improving back-office finance operations.
- [AR by Industry](https://www.rex.inc/resources/industries): How accounts receivable works in specific industries, with the collection patterns, terms, and risks that matter in each.
- [AR Metrics & KPIs](https://www.rex.inc/resources/ar-metrics): The metrics that measure receivables health: DSO, CEI, ADD, aging, and how to benchmark them.
- [AI & Agentic AR](https://www.rex.inc/resources/ai-ar): How agentic AI changes accounts receivable: what an AI AR agent does, how it differs from RPA and dashboards, and where it recovers cash.
- [Accounts Receivable Automation](https://www.rex.inc/resources/ar-automation): Practical guides to automating accounts receivable: collections, cash application, dunning, and the operating model behind a modern AR function.
- [Customer Portals & Invoice Delivery](https://www.rex.inc/resources/customer-portals): Operating the AP portals customers require, and getting invoices delivered through every channel they use.
- [Disputes & Deductions](https://www.rex.inc/resources/disputes-deductions): Finding the root cause of disputes and deductions, routing them fast, and recovering what is owed.
- [Collections & Dunning](https://www.rex.inc/resources/collections): Chasing overdue invoices without burning relationships: cadences, escalation, prioritization, and automating dunning.
- [Finance Operations Glossary](https://www.rex.inc/resources/glossary): Plain-English definitions of the AR, collections, and order-to-cash terms that show up in every finance operations conversation.
- [Templates](https://www.rex.inc/resources/templates): Ready-to-use templates for collections emails, payment plans, and customer outreach.
- [Cash Application](https://www.rex.inc/resources/cash-application): Matching payments to invoices at scale, including remittance, short pays, and straight-through auto-application.
- [Credit & Risk](https://www.rex.inc/resources/credit-management): Setting credit policy, limits, and onboarding checks that protect cash without slowing down sales.
- [Invoicing & Billing](https://www.rex.inc/resources/invoicing-billing): Getting invoices right the first time so they get paid: accuracy, e-invoicing, and reliable delivery.
- [CFO & Working Capital](https://www.rex.inc/resources/cfo-strategy): Working capital, cash flow, and the strategic case for a faster, leaner receivables function, written for finance leaders.
- [Order-to-Cash](https://www.rex.inc/resources/order-to-cash): How the order-to-cash cycle actually works, where it breaks, and how finance teams are compressing it with agentic systems.

## Customer stories
- [How Synthesia transformed order-to-cash into an AI-native operation](https://www.rex.inc/customers/synthesia): Synthesia is a fast-growing AI video platform whose finance team runs enterprise AR through Gmail, NetSuite, Salesforce, and dozens of customer portals.

## Blog
- [Rex is live on Y Combinator](https://www.rex.inc/blog/rex-launch-yc): Our YC launch is live. Rex is an AI service that runs order-to-cash and accounts receivable operations for enterprises, with agents that do the work and a team that approves exceptions.
- [Rex joins Y Combinator (S26)](https://www.rex.inc/blog/rex-joins-y-combinator-s26): Rex is part of the Y Combinator Summer 2026 batch. We're building the AI operations partner for enterprise order to cash.
- [Rex joins NVIDIA's Adopt 100 Launch](https://www.rex.inc/blog/nvidia-adopt-100-launch): Rex has been selected for Adopt 100, Deloitte and NVIDIA's program pairing leading AI startups with enterprise customers to deploy AI at scale.
- [Rex wins the Vercel AI Accelerator](https://www.rex.inc/blog/rex-wins-vercel-ai-accelerator): A panel of founders and AI leaders selected Rex as the winner of the Vercel AI Accelerator Demo Day — out of 2,500 applicants.
- [AI-shoring operational finance](https://www.rex.inc/blog/ai-shoring-operational-finance): Operational finance has always scaled linearly with revenue. Agentic systems change that — and shift the role of the operator.
- [The knowledge gap in enterprise AI](https://www.rex.inc/blog/the-knowledge-gap-in-enterprise-ai): Context windows don't solve on-the-job learning when the knowledge was never written down. A taxonomy of enterprise knowledge, and how agents can capture the tacit parts.
- [Most finance work is reconstructing the story](https://www.rex.inc/blog/most-finance-work-is-reconstructing-the-story): For finance AI to work, we need a context layer. Without it, agents are just guessing.
- [Context graphs in finance operations](https://www.rex.inc/blog/context-graphs-in-finance-operations): Systems of context will become the most business-critical system in the AI era. A thesis on how this plays out in finance operations.

## Key pages
- [Platform](https://www.rex.inc/platform): How the Rex platform works: understand, instruct, improve, simulate, audit.
- [Customer setup](https://www.rex.inc/customer-setup): Agents keep customer contact, billing, and account details up to date.
- [AR inbox](https://www.rex.inc/ar-inbox): Customer emails triaged, answered, or routed in minutes.
- [Order & PO readiness](https://www.rex.inc/order-po-readiness): Validate orders against POs, terms, and billing requirements.
- [Collections](https://www.rex.inc/collections): Agents follow up with every customer, 24/7.
- [Customer portal operations](https://www.rex.inc/customer-portal-operations): Submit invoices and reconcile POs across buyer portals.
- [Disputes and deductions](https://www.rex.inc/disputes): Deductions investigated, documented, then resolved or contested.
- [Cash application](https://www.rex.inc/cash-application): Research agents match low-signal payments to invoices.
- [Compass](https://www.rex.inc/compass): Order-to-cash process mapping and diagnostics.
- [BPO partners](https://www.rex.inc/bpo): Rex for finance operations providers.
- [Customers](https://www.rex.inc/customers): Customer stories.
- [Company](https://www.rex.inc/company)
- [Contact](https://www.rex.inc/contact)
- [For agents](https://www.rex.inc/agents): Rex is a managed service. There is no public product API.
- [Pricing](https://www.rex.inc/pricing): Outcome-based for production workspaces.
- [MCP server](https://www.rex.inc/mcp): Streamable HTTP tools to list, search, and fetch public Rex pages as Markdown.
- [Agent Skills index](https://www.rex.inc/.well-known/agent-skills/index.json): Skills for the site MCP and Markdown negotiation.
- [FAQ](https://www.rex.inc/faq)
- [How Rex uses and secures AI](https://www.rex.inc/ai-security): How Rex uses large language models, handles customer data, and what security guardrails are in place.

## When to use Rex

Use Rex when the job is accounts receivable operations: collections follow-ups, dispute packets, buyer-portal submissions, and cash application.
- Read product facts as Markdown (`Accept: text/markdown` or sibling `.md` URLs); start at this file.
- Search and fetch this site as Markdown via Streamable HTTP MCP at `/mcp` (`rex_search`, `rex_get_page`).
There is no public Rex API or sandbox. Production workspaces are scoped with the finance team. Full guidance: https://www.rex.inc/agents.

## For AI agents
Request any public URL with `Accept: text/markdown` (or the sibling `.md` path) to receive a Markdown representation. Missing paths return HTTP 404 with recovery links.
- Markdown homepage: https://www.rex.inc/index.md
- Contact: https://www.rex.inc/contact

Sitemap: https://www.rex.inc/sitemap.xml