# Brex vs Payhawk API + MCP

> Brex scores 60.7 (C) on agent readiness against Payhawk API + MCP's 57.1 (C), and leads in 6 of 7 scored categories. Payhawk API + MCP leads on transparency & trust. Both do spend transactions. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/brex-vs-payhawk
- Markdown: https://www.anchorterminal.com/compare/brex-vs-payhawk.md (~2,150 tokens)
- Slim: https://www.anchorterminal.com/compare/brex-vs-payhawk.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/brex-vs-payhawk.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Brex scores 60.7 (C) on agent readiness against Payhawk API + MCP's 57.1 (C), and leads in 6 of 7 scored categories. Payhawk API + MCP leads on transparency & trust. Both do spend transactions.

- Brex: grade C, 60.7/100, rank #452 of 842. Markdown https://www.anchorterminal.com/tools/brex.md · JSON https://www.anchorterminal.com/api/v1/tools/brex.json
- Payhawk API + MCP: grade C, 57.1/100, rank #561 of 842. Markdown https://www.anchorterminal.com/tools/payhawk.md · JSON https://www.anchorterminal.com/api/v1/tools/payhawk.json

## Which one, for what

### Brex (C)

Good for: A finance team already on Brex that wants an agent to read expenses and transactions, issue and lock cards, set spend limits, upload receipts and pay vendors.

Ahead on:
- Schema & documentation, 80 against 71
- Agent ergonomics, 70 against 52
- Payments & pricing, 25 against 13
- Maintenance & community, 66 against 53

Watch for: The Expenses API update endpoint accepts only `memo`, so an outside agent can't set a category or custom field on an expense through it

### Payhawk API + MCP (C)

Good for: A finance team already on Payhawk that wants an ERP or accounting sync, master data kept in step, purchase orders raised from another system, or an assistant that answers spend questions and prepares approvals.

Ahead on:
- Transparency & trust, 78 against 67

Also in its favour:
- No incidents deducted, where Brex loses 3 points for them

Watch for: No self-serve route. The API needs a Payhawk customer account, and a development sandbox is requested through a form


## Score by category

| Category | Weight | Brex | Payhawk API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 58 | Brex +2 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 71 | Brex +9 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 52 | Brex +18 |
| Security & auth | 14% (17.5 this run) | 72 | 71 | Brex +1 |
| Payments & pricing | 10% (12.5 this run) | 25 | 13 | Brex +12 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 66 | 53 | Brex +13 |
| Transparency & trust | 7% (8.8 this run) | 67 | 78 | Payhawk API + MCP +11 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **60.7 · C** | **57.1 · C** | |

## Facts side by side

| Fact | Brex | Payhawk API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Brex LLC | Payhawk Limited |
| Hosted endpoint | `https://api.brex.com` | `https://api.payhawk.com` |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Paid |
| x402 | no | no |
| Licence | Proprietary service under the Brex Platform Agreement and the Brex Access Agreement | Proprietary service under Payhawk's general terms and conditions |
| Tools exposed | 43 | 82 |
| Read-only variant documented | yes | yes |
| llms.txt | yes | yes |
| Last release | 2026-10-01 | 2026-10-08 |
| Terms last updated | no date given | 2025-12-09 |
| Privacy policy last updated | no date given | 2026-06-29 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |

## Verdicts

**Brex.** User tokens carry per-resource scopes with read-only variants, every POST and PUT accepts an `Idempotency-Key`, and ten OpenAPI specs are public. The Expenses API changes only an expense's memo, there is no customer sandbox or official SDK, and the status page logs API errors lasting over four hours on 4 August 2026.

**Payhawk API + MCP.** The Developer API has a public OpenAPI 3.1 definition with 179 operations, read-only or full-access keys and a published limit of 15 requests a second. It needs a Payhawk customer account, no official SDK or API changelog was found, and the 82-tool MCP server is added by hand because it is not yet in the assistant directories.

## Before you call either

### Brex

1. Ask an account admin or card admin for a user token with only the scopes the task needs, and prefer the `.readonly` variants. A token unused for 90 days expires.
2. Send a stored `Idempotency-Key` on every POST and PUT. Create transfer and Create card reject requests without one.
3. Only settled transactions are returned. Poll card and cash transactions with `posted_at_start` and a lookback of at least one day.
4. Keep under 1,000 requests in 60 seconds per client and account, and back off exponentially with jitter on 429.
5. Send only ASCII in free-text fields, and quote the `X-Brex-Trace-Id` response header when reporting an error.

### Payhawk API + MCP

1. Send the key in `X-Payhawk-ApiKey` or as a Bearer token to `https://api.payhawk.com/api/v3`. A read-only key returns 403 on writes
2. Page lists with `$skip` and `$take`. The help centre gives 1,000 a page and the definition a maximum of 10,000, so count what comes back
3. Pass `$filter` as URL-encoded JSON, for example `{"status":{"$equal":"draft"}}`. Date filters compare the date part only
4. Keep to 15 requests a second and wait for `Retry-After` on a 429. Do not send `Idempotency-Key` when creating a per diem expense, which returns 400
5. Use a group-level key and the `/groups/{groupId}` paths for master data in a multi-entity group. Expenses and payments stay on account paths

## Questions

### Which is better for AI agents, Brex or Payhawk API + MCP?

Brex scores 60.7 (C) on agent readiness against Payhawk API + MCP's 57.1 (C), and leads in 6 of 7 scored categories. Payhawk API + MCP leads on transparency & trust.

### Do Brex and Payhawk API + MCP need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call Brex and Payhawk API + MCP without installing anything?

Yes. Brex has a hosted endpoint at https://api.brex.com and Payhawk API + MCP at https://api.payhawk.com.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/brex-vs-payhawk.json, and with the fewest tokens: https://www.anchorterminal.com/compare/brex-vs-payhawk.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "brex", "b": "payhawk"}`. From a terminal: `anchor compare brex payhawk`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/brex.json and https://www.anchorterminal.com/api/v1/tools/payhawk.json

## Other comparisons with Brex or Payhawk API + MCP

- [Airwallex Spend and Issuing vs Brex](https://www.anchorterminal.com/compare/airwallex-vs-brex.md)
- [Airwallex Spend and Issuing vs Payhawk API + MCP](https://www.anchorterminal.com/compare/airwallex-vs-payhawk.md)
- [BILL vs Brex](https://www.anchorterminal.com/compare/bill-vs-brex.md)
- [BILL vs Payhawk API + MCP](https://www.anchorterminal.com/compare/bill-vs-payhawk.md)
- [Brex vs Expensify](https://www.anchorterminal.com/compare/brex-vs-expensify.md)
- [Brex vs Mercury API](https://www.anchorterminal.com/compare/brex-vs-mercury.md)
- [Brex vs Pleo API + MCP](https://www.anchorterminal.com/compare/brex-vs-pleo.md)
- [Brex vs Ramp](https://www.anchorterminal.com/compare/brex-vs-ramp.md)
- [Brex vs Spendesk API + MCP](https://www.anchorterminal.com/compare/brex-vs-spendesk.md)
- [Expensify vs Payhawk API + MCP](https://www.anchorterminal.com/compare/expensify-vs-payhawk.md)
- [Mercury API vs Payhawk API + MCP](https://www.anchorterminal.com/compare/mercury-vs-payhawk.md)
- [Payhawk API + MCP vs Pleo API + MCP](https://www.anchorterminal.com/compare/payhawk-vs-pleo.md)
- [Payhawk API + MCP vs Ramp](https://www.anchorterminal.com/compare/payhawk-vs-ramp.md)
- [Payhawk API + MCP vs Spendesk API + MCP](https://www.anchorterminal.com/compare/payhawk-vs-spendesk.md)