Brex Inc., the San Francisco-based fintech powerhouse serving over 35,000 companies from startups to enterprises like Anthropic and DoorDash, has launched an AI-native Accounting API that promises to eradicate the drudgery of month-end closes. Unveiled on January 22, 2026, the API enables continuous, two-way data exchange with enterprise resource planning systems, supplanting outdated one-way bank feeds with real-time transaction syncing and policy enforcement.

This development arrives amid Brex’s aggressive push into intelligent finance, where AI agents handle everything from expense coding to ledger reconciliation. The API integrates directly with Brex’s core accounting engine, delivering pre-coded, validated transactions to ERPs via webhooks and expanded endpoints. Finance teams can now enforce spending rules at the point of transaction, capturing context like merchant details and approvals upfront for seamless ERP ingestion.

“With accounting, accuracy and speed can’t be trade-offs,” Brex Chief Technology Officer James Reggio told PR Newswire. “Our AI-native Accounting API brings intelligent automation and real-time, enriched data to finance teams and their ERP partners, executing work like coding transactions and preparing exports on their behalf so they can close the books faster with confidence.”

Breaking the Batch Processing Bottleneck

Traditional accounting relies on periodic batch exports, leading to delays, errors, and manual reconciliations that plague finance operations. Brex’s API flips this model by triggering immediate notifications on new activity, allowing ERPs to receive audit-ready data without human intervention. When paired with Brex’s recent AI capabilities—such as automated workflows that have already eliminated over 10,000 hours of manual work monthly—the system supports a “zero-day close,” where ledgers remain perpetually current across prepaids, accruals, and multi-entity consolidations.

Initial rollouts target AI-native ERPs Rillet and Campfire. Rillet founder and CEO Nicolas Kopp highlighted the synergy: “The manual month-end close is a relic. At Rillet, we believe in the zero-day close. By pairing Brex’s real-time data with Rillet’s automation engine, your ledger is always current from prepaids to accruals to multi-entity consolidation. Your finance team can start acting on audit-ready financials in real time,” he said in comments reported by International Accounting Bulletin.

Brex Director of Engineering Antoine Azar emphasized the API’s architectural depth on X: “Unlike traditional APIs that sit beside the product, this one is built into Brex’s AI-powered accounting core. It’s real-time and event-driven (webhooks, not polling), bidirectional, and shares the same intelligence as our Accounting Journal.”

Embedded Intelligence Drives Adoption

The API builds on Brex’s Accounting Journal and sub-ledger, which ingests data from cards, reimbursements, and bills while handling complex scenarios like multi-entry events for accruals. AI suggests optimal GL codes with 90% acceptance rates, automates merchant mapping, and validates against ERP rules pre-export. This has accelerated closes by 3x for users, per Brex metrics shared in product updates.

Campfire, the other launch partner, aligns with Brex’s vision for agentic finance. Brex’s X announcement framed it as “Autonomous accounting is here,” with the API enforcing policies, suggesting mappings, and closing books hands-free. Early adopters like Plaid’s Head of GL Accounting Sophie Chiang noted: “Brex has made a huge impact. The pre-filled memos, the auto-categorization, the AI suggestions. Their constant AI rollouts are helping us move faster,” as quoted in a Brex press release.

For industry insiders, the API’s event-driven design—leveraging webhooks for instant alerts—marks a shift from polling-based integrations common in legacy systems like NetSuite or QuickBooks. It supports two-way sync, pulling ERP fields into Brex for point-of-spend compliance, a feature TipRanks called key to embedding Brex deeper into core finance stacks.

Strategic Timing Amid Fintech Consolidation

Launched just before reports of Capital One’s $5.15 billion acquisition interest surfaced on X and in whispers across fintech circles, the API underscores Brex’s evolution from corporate cards to a full finance OS. Valued at $12.3 billion in 2022, Brex has pivoted to high-margin software, with products like cards, reimbursements, and bill pay crossing $100 million in revenue each.

The timing amplifies Brex’s appeal to incumbents seeking AI-native infrastructure. As PR Newswire detailed, the API removes synchronization gaps, automating from “swipe to close” regardless of ERP. This positions Brex as indispensable for scaling firms in 120+ countries, boosting stickiness via switching costs.

Competitors like Ramp and Stripe offer integrations, but Brex’s native AI—rooted in years of sub-ledger development—delivers proactive automation. Brex’s API documentation and developer portal further enable custom workflows, from programmatic card issuance to vendor onboarding.

AI Agents Power the Next Frontier

Brex’s broader AI ecosystem, including the Agent Mesh announced earlier, underpins the API. Networks of specialized agents communicate in natural language to audit spend, resolve issues, and run reports via queries. CTO Reggio described it to VentureBeat as making Brex “effectively disappear,” with agents handling totality of responsibilities like policy enforcement and travel requests.

Customer testimonials reinforce impact: Brex’s AI has saved 169,000 accounting hours monthly, per Bank Automation News. For enterprises, this means leaner teams focusing on strategy over spreadsheets.

Expansion plans hint at broader ERP support beyond Rillet and Campfire, potentially including NetSuite and Intacct. As finance digitizes, Brex’s API sets a benchmark for real-time, intelligent connectivity, compelling rivals to accelerate their own AI integrations.

Implications for Enterprise Finance

Insiders view this as infrastructure play: Brex owns the data flow, enabling predictive lending and real-time insights traditional banks lack. The API’s idempotency ensures no duplicates, even on errors, while immutability supports audits.

With Brex’s global reach and AI-first design, the Accounting API not only automates but anticipates needs, from custom fields syncing HRIS data to AI policy engines applying nuanced rules. As adoption grows, it could redefine ERP dependencies, turning finance into a continuous, proactive function.