Brex vs Castellum.AI: Which Finance AI Is Better in 2026?
Compare pricing, features, integrations, verified reviews, AI capabilities, security, and customer satisfaction, side by side, with no marketing spin.
The Short Answer
Brex vs Castellum.AI, in 15 seconds
Choose Brex if…
- You want the lower entry price
- You need a genuinely free plan
Choose Castellum.AI if…
- You want deeper AI and automation features
- You have strict security & compliance needs
Head-to-Head Scorecard
How Brex and Castellum.AI score
Brex leads on 3 of 9 measured dimensions.
- Even
Customer Rating
Average score from verified user reviews
BrexNo reviewsCastellum.AINo reviews - Even
Review Volume
Number of verified reviews, a proxy for adoption
Brex0Castellum.AI0 - Brex
Entry Pricing
Lowest published starting price (free plan = lowest)
Brex$12/moCastellum.AICustom - Brex
Free Access
Availability of a free plan and/or free trial
BrexFree planCastellum.AIPaid only - Even
Integrations
Number of listed third-party integrations
Brex6Castellum.AI6 - Even
Features
Number of listed product capabilities
Brex6Castellum.AI6 - Castellum.AI
AI Features
Capabilities mentioning AI, automation or ML
Brex1Castellum.AI2 - Castellum.AI
Security & Compliance
Number of listed compliance certifications
Brex2Castellum.AI3 - Brex
Platforms & Deployment
Supported platforms and deployment options
Brex4Castellum.AI3
Feature Comparison
Brex vs Castellum.AI feature breakdown
Search or filter the full feature matrix, core features, AI, integrations, APIs, security and compliance.
Brex
Castellum.AIPricing Comparison
Brex vs Castellum.AI pricing
Entry pricing, plan tiers and the cost factors that shape total cost of ownership.
Brex
$12/mo to start- Global cards
- AI-powered rules
- Accounting integrations
- Real-time reporting
- Per user
- Customizable expense policies
- Dynamic expense review chains
- Compliance audit detection
- Unlimited entities
- Local card issuance
- Named account manager
Castellum.AI
Custom to start- Sanctions and PEP data
- Arbiter AI agents
- Contact vendor for quote
Total cost of ownership factors
Beyond list price, factor in implementation, training, add-ons and per-seat scaling when estimating total cost of ownership.
Pros & Cons
Brex vs Castellum.AI: strengths and trade-offs
Brex
Pros
- Free plan available
- Compliance: SOC 1, SOC 2
- Public API available
Cons
Castellum.AI
Pros
- Compliance: SOC 2, ISO 27001, GDPR
- Stronger AI / automation features
- Public API available
Cons
- No free plan
- No free trial
- Pricing is quote-based (less transparent)
Buyer Fit
Who should use Brex vs Castellum.AI?
Startups
Brex
Brex keeps early-stage costs lowest with its entry tier.
Small businesses
Brex
Brex offers the most accessible pricing for lean teams.
Agencies
Either
Either connects to more tools for multi-client workflows.
Enterprises
Castellum.AI
Castellum.AI leads on compliance and breadth for complex needs.
Ecommerce
Castellum.AI
Castellum.AI integrates with more of the commerce stack.
SaaS companies
Castellum.AI
Castellum.AI is the more developer- and automation-friendly choice.
Integration overlap
Shared integrations (1)
Only in Brex (5)
Only in Castellum.AI (5)
Keep Exploring
Other alternatives worth considering
Similar finance ai products buyers compare alongside Brex and Castellum.AI.
Ask SIA which solution fits your business
SIA, Saaskart's AI buying assistant, weighs Brex and Castellum.AI against your team size, budget, integrations and compliance needs, then recommends the right fit and the questions to ask each vendor.
Get a personalised recommendationBrex vs Castellum.AI, Frequently Asked Questions
What is the difference between Brex and Castellum.AI?
Brex and Castellum.AI are both Finance AI solutions. Brex is rated 0.0/5 by 0 users, while Castellum.AI is rated 0.0/5 by 0 users. The main differences lie in pricing, features, and target audience.
Which is better, Brex or Castellum.AI?
Based on user ratings, Brex scores higher at 0.0/5. The best choice depends on your team size, budget, and specific requirements.
Which is cheaper, Brex or Castellum.AI?
Brex is the more affordable option, starting at $12/month.
Does Brex or Castellum.AI have a free plan?
Brex offers a free plan. Castellum.AI does not have a free tier but offers paid plans.
Can I switch from Brex to Castellum.AI?
Switching between Brex and Castellum.AI is possible. Both support data export. Check integration compatibility and plan for data migration to minimise disruption to your team.
Who should use Brex vs Castellum.AI?
Brex is best suited for teams that prioritise enterprise features. Castellum.AI works well for teams needing advanced capabilities.
Our Verdict
The bottom line on Brex vs Castellum.AI
Best Overall
Either
It's a tie balances user satisfaction and proven adoption.
Best for Startups
Brex
Brex has the friendliest entry point for new teams.
Best for Enterprise
Castellum.AI
Castellum.AI leads on compliance and feature breadth.
Best Value
Brex
Brex delivers the lowest cost to get started.
Best AI Features
Castellum.AI
Castellum.AI ships more AI and automation.
Highest Rated
Either
Both earn equal user ratings.