# Check vs Salsa

> Check scores 67.5 (B) on agent readiness against Salsa's 46.1 (D), and leads in 6 of 7 scored categories. Both do payroll run. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/check-payroll-vs-salsa
- Markdown: https://www.anchorterminal.com/compare/check-payroll-vs-salsa.md (~2,150 tokens)
- Slim: https://www.anchorterminal.com/compare/check-payroll-vs-salsa.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/check-payroll-vs-salsa.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: 2026-10-08

Check scores 67.5 (B) on agent readiness against Salsa's 46.1 (D), and leads in 6 of 7 scored categories. Both do payroll run.

- Check: grade B, 67.5/100, rank #208 of 722. Markdown https://www.anchorterminal.com/tools/check-payroll.md · JSON https://www.anchorterminal.com/api/v1/tools/check-payroll.json
- Salsa: grade D, 46.1/100, rank #651 of 722. Markdown https://www.anchorterminal.com/tools/salsa.md · JSON https://www.anchorterminal.com/api/v1/tools/salsa.json

## Which one, for what

### Check (B)

Good for: A software platform that wants to sell US payroll inside its own product and can sign a partnership, with Check handling tax calculation, money movement and filings.

Ahead on:
- Reliability, 80 against 36
- Schema & documentation, 78 against 73
- Agent ergonomics, 83 against 48
- Security & auth, 74 against 56
- Maintenance & community, 72 against 50
- Transparency & trust, 62 against 51

Watch for: No public price and no self-serve signup. The documentation says to request an API key through Check's sales contact

### Salsa (D)

Good for: A software platform that wants to sell payroll to its own business customers and can sign a partner agreement, with Salsa handling tax filing and money movement.

Watch for: API tokens come from Salsa after a sales contact. No self-serve signup, public price, free tier or trial was found


## Score by category

| Category | Weight | Check | Salsa | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 80 | 36 | Check +44 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 73 | Check +5 |
| Agent ergonomics | 13% (16.2 this run) | 83 | 48 | Check +35 |
| Security & auth | 14% (17.5 this run) | 74 | 56 | Check +18 |
| Payments & pricing | 10% (12.5 this run) | 5 | 5 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 50 | Check +22 |
| Transparency & trust | 7% (8.8 this run) | 62 | 51 | Check +11 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67.5 · B** | **46.1 · D** | |

## Facts side by side

| Fact | Check | Salsa |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Check Technologies, Inc. | Salsa Software Inc. |
| Hosted endpoint | `https://api.checkhq.com` | `https://api.salsa.dev/api/rest/v1` |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under Check's terms of service and partner agreement. The MCP server and CLI on GitHub are MIT | Proprietary service. The website Terms of Use are public and the partner agreement isn't. The browser library @salsa-payroll/salsa-js on npm is MIT |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | 2026-10-07 | 2026-10-07 |
| Terms last updated | 2021-09-03 | 2022-04-07 |
| Privacy policy last updated | 2024-04-18 | 2025-09-24 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 18 stars | 435 npm/wk |

## Verdicts

**Check.** Graded as embedded payroll through a partner API key, not access to an existing employer's payroll account. The API has idempotency keys on writes, a required preview before approval and queryable request logs. No price is public, a sandbox key comes through Check's sales team, and one API key carries the whole partner account.

**Salsa.** Salsa is reached as an embedded-payroll partner, not through an employer's existing payroll account. The REST API has a public OpenAPI 3.1 spec with 123 operations, a payroll preview, a separate confirm step and short-lived user tokens limited by role. Access starts with a sales conversation, and no public price, self-serve sandbox, status page or API changelog was found.

## Before you call either

### Check

1. Use https://sandbox.checkhq.com with the sandbox key and https://api.checkhq.com with the production key. A key is not valid across environments
2. Preview a payroll before approving it, then pass `preview_started_at` to POST /payrolls/{id}/approve so a stale preview fails with 409
3. Send `X-Idempotency-Key` on every write. Keys expire after 24 hours, so list the resource before retrying later than that
4. On 429 wait for `Retry-After`. The limit is 10 requests a second in sandbox and for partners paying fewer than 1,000 payees a month, with 100 concurrent requests
5. Connect the MCP server with `?read_only=true` or `X-MCP-Readonly: true` unless writes are intended. In production, approving a payroll moves money

### Salsa

1. Use the sandbox token against https://api.sandbox.salsa.dev and the production token against https://api.salsa.dev. Each environment has its own token
2. Call POST /payroll-runs/preview before creating a run, then confirm the PENDING run in a separate call. Confirming starts the employer debit
3. Send your own externalId on every create. A repeat returns a uniqueness error, which is the only duplicate protection
4. Make sure externalId values are unique across all employers, since each entity type has one namespace
5. Mint a user token with the lowest role and the fewest employerIds the task needs, and keep the partner token on the server

## Questions

### Which is better for AI agents, Check or Salsa?

Check scores 67.5 (B) on agent readiness against Salsa's 46.1 (D), and leads in 6 of 7 scored categories.

### Do Check and Salsa need an API key?

Check takes an API key or an OAuth sign-in. Salsa needs an API key.

### Can an agent call Check and Salsa without installing anything?

Yes. Check has a hosted endpoint at https://api.checkhq.com and Salsa at https://api.salsa.dev/api/rest/v1.


## For agents

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

## Other comparisons with Check or Salsa

- [Argyle vs Check](https://www.anchorterminal.com/compare/argyle-vs-check-payroll.md)
- [Argyle vs Salsa](https://www.anchorterminal.com/compare/argyle-vs-salsa.md)
- [Check vs Finch](https://www.anchorterminal.com/compare/check-payroll-vs-finch.md)
- [Check vs Paychex](https://www.anchorterminal.com/compare/check-payroll-vs-paychex.md)
- [Finch vs Salsa](https://www.anchorterminal.com/compare/finch-vs-salsa.md)
- [Paychex vs Salsa](https://www.anchorterminal.com/compare/paychex-vs-salsa.md)
- [Check vs Employment Hero Payroll](https://www.anchorterminal.com/compare/check-payroll-vs-employment-hero.md)
- [Check vs Everee](https://www.anchorterminal.com/compare/check-payroll-vs-everee.md)
- [Check vs Gusto](https://www.anchorterminal.com/compare/check-payroll-vs-gusto.md)
- [Check vs Zeal](https://www.anchorterminal.com/compare/check-payroll-vs-zeal.md)
- [Employment Hero Payroll vs Salsa](https://www.anchorterminal.com/compare/employment-hero-vs-salsa.md)
- [Everee vs Salsa](https://www.anchorterminal.com/compare/everee-vs-salsa.md)
- [Gusto vs Salsa](https://www.anchorterminal.com/compare/gusto-vs-salsa.md)
- [Salsa vs Zeal](https://www.anchorterminal.com/compare/salsa-vs-zeal.md)