Accounts Payable (AP) Specialist at Castelion in Torrance, CA
- Company: Castelion
- Location: Torrance, CA
- Posted: Sep 17, 2026
- Type: Full-time
- Experience: 3+ years
Overview
We are seeking an experienced Accounts Payable (AP) Specialist to join our growing accounting team. This will be the second AP Specialist on the team and will directly support our Senior Accounting Manager. The AP Specialist will be responsible for ensuring accurate and timely processing of vendor i…
Job description
- We are seeking an experienced Accounts Payable (AP) Specialist to join our growing accounting team. This will be the second AP Specialist on the team and will directly support our Senior Accounting Manager. The AP Specialist will be responsible for ensuring accurate and timely processing of vendor invoices, payments, and employee expense reports. The ideal candidate is detail-oriented, organized, and thrives in a fast-paced, dynamic environment where accuracy and accountability are critical.
Responsibilities
- Review, code, and process vendor invoices in compliance with company policies and procedures.
- Manage the AP inbox and vendor communications, ensuring timely responses.
- Assist with the three-way matching process (PO, receipt, and invoice) and resolve discrepancies.
- Partner with Supply Chain and Engineering departments to reconcile item receipts, including quantities and prices, between procurement and expense management platforms.
- Confirm vendor payment details and process check runs, ACH payments, and wire transfers to ensure timely payment of invoices.
- Reconcile vendor statements and follow up on outstanding balances.
- Ensure compliance with internal controls and audit requirements.
- Support monthly, quarterly, and year-end close activities, including AP accruals.
- Manage the employee corporate card program, including processing monthly expense reports, employee reimbursements, and corporate credit card reconciliations.
- Provide ad hoc support to the Senior Accounting Manager as needed.
Requirements
- 3+ years of accounts payable experience, preferably in manufacturing, aerospace, or defense.
- Strong understanding of GAAP and accounting processes related to AP.
- Proficiency with ERP systems (NetSuite experience preferred), expense management platforms (Ramp), procurement platforms (Silkline), and Excel.
- Exceptional attention to detail, accuracy, and organizational skills.
- Strong communication and problem-solving abilities.
- Ability to thrive in a fast-paced, hands-on environment and meet tight deadlines.
- U.S. Person status required due to government program requirements.
- Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.
Skills
Required
- Accounts payable
- GAAP
- ERP systems
- Excel
- Attention to detail
- Organizational skills
- Communication
- Problem-solving
- Fast-paced environment
- Meeting tight deadlines
Preferred
- NetSuite
- Ramp
- Silkline
About Castelion
Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability. This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.