# Karrio vs ShipStation API

> ShipStation API scores 59.3 (C) on agent readiness against Karrio's 48.7 (D), and leads in 4 of 7 scored categories. Karrio leads on reliability and security & auth. Both do shipping rates. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/karrio-vs-shipstation
- Markdown: https://www.anchorterminal.com/compare/karrio-vs-shipstation.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/karrio-vs-shipstation.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/karrio-vs-shipstation.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

ShipStation API scores 59.3 (C) on agent readiness against Karrio's 48.7 (D), and leads in 4 of 7 scored categories. Karrio leads on reliability and security & auth. Both do shipping rates.

- Karrio: grade D, 48.7/100, rank #617 of 722. Markdown https://www.anchorterminal.com/tools/karrio.md · JSON https://www.anchorterminal.com/api/v1/tools/karrio.json
- ShipStation API: grade C, 59.3/100, rank #433 of 722. Markdown https://www.anchorterminal.com/tools/shipstation.md · JSON https://www.anchorterminal.com/api/v1/tools/shipstation.json

## Which one, for what

### Karrio (D)

Good for: A team that wants to host its own multi-carrier API with its own carrier contracts and can maintain a Django and PostgreSQL stack.

Ahead on:
- Reliability, 76 against 64
- Security & auth, 44 against 32

Also in its favour:
- Open source

Watch for: No release since 2026.1.32 on 23 June 2026, 107 days before this check, and fix pull requests opened in September 2026 were still open

### ShipStation API (C)

Good for: An agent working inside a merchant's existing ShipStation account (orders, batches, inventory, labels), or a developer who wants a free sandbox through the ShipStation API plans.

Ahead on:
- Schema & documentation, 83 against 68
- Agent ergonomics, 64 against 57
- Maintenance & community, 73 against 29
- Transparency & trust, 64 against 56

Also in its favour:
- A hosted endpoint, with nothing to install
- No incidents deducted, where Karrio loses 7 points for them

Watch for: One API key with full account access. No scopes, read-only keys or approval step before a label is bought


## Score by category

| Category | Weight | Karrio | ShipStation API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 76 | 64 | Karrio +12 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 68 | 83 | ShipStation API +15 |
| Agent ergonomics | 13% (16.2 this run) | 57 | 64 | ShipStation API +7 |
| Security & auth | 14% (17.5 this run) | 44 | 32 | Karrio +12 |
| Payments & pricing | 10% (12.5 this run) | 40 | 40 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 29 | 73 | ShipStation API +44 |
| Transparency & trust | 7% (8.8 this run) | 56 | 64 | ShipStation API +8 |
| Negative events | ≤15 | -7 | 0 | |
| **Total** | | **48.7 · D** | **59.3 · C** | |

## Facts side by side

| Fact | Karrio | ShipStation API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Karrio, Inc. | Auctane LLC d/b/a ShipStation |
| Hosted endpoint | no (local only) | `https://api.shipstation.com/v2` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | LGPL-3.0 for the server, SDK and modules. Code under `ee/` is under the Karrio Enterprise licence and needs a subscription for production use. The MCP package in `packages/mcp` is Apache-2.0 | Proprietary service under ShipStation's terms of service. The v2 OpenAPI file is marked MIT and the SDKs on GitHub are Apache 2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-06-23 | 2026-10-01 |
| Terms last updated | 2025-04-08 | no date given |
| Privacy policy last updated | 2025-04-08 | 2026-03-18 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | yes | 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 | 799 stars, 338 PyPI/wk | 6.8k npm/wk |

## Verdicts

**Karrio.** A current OpenAPI 3.0.3 contract with 65 paths, a free LGPL-3.0 server and 30 carrier connectors suit a team that hosts it. The last release was 23 June 2026, the `@karrio/mcp` package the docs install is absent from npm, and `api.karrio.io` didn't resolve on 8 October 2026.

**ShipStation API.** A public OpenAPI 3.1 contract with 173 operations, Markdown docs for agents and a free ShipStation API plan with a sandbox make a first rate quote or test label reachable without a contract. One API key carries full account access, with no scopes, read-only mode or idempotency keys on label purchases.

## Before you call either

### Karrio

1. Run your own instance with Docker Compose and call it at `http://localhost:5002`. Don't rely on `api.karrio.io`, which didn't resolve on 8 October 2026
2. Don't run `npx karrio-mcp` or `npx -y @karrio/mcp`. Neither name is published on npm, so build the server from `packages/mcp` in the repository
3. Change the default `admin@example.com` and `demo` login before the instance is reachable, and upgrade to 2026.1.32 or later so passwords aren't stored as MD5
4. Don't blind-retry `POST /v1/shipments` with a `service` set or `POST /v1/shipments/{id}/purchase`. Fetch the shipment and check its status first, since no idempotency key exists
5. Use a test-mode API key while building. Send it as the HTTP Basic username or as `Authorization: Token key_...`

### ShipStation API

1. Send the key in an `API-Key` header to https://api.shipstation.com/v2. A key that starts `TEST_` runs in the sandbox on the same host
2. Call GET /v2/carriers first. Rate and label calls need `carrier_ids` or a `carrier_id` and a `service_code` from that account
3. Don't blindly retry POST /v2/labels after a timeout. List labels first, then void a duplicate with PUT /v2/labels/{label_id}/void
4. Check the `errors` array on 2XX responses too, and read `error_source` to tell a carrier fault from a ShipStation one
5. On a platform (Standard or Premium) key every label is real and charged. Ask the owner before buying, and void test labels at once

## Questions

### Which is better for AI agents, Karrio or ShipStation API?

ShipStation API scores 59.3 (C) on agent readiness against Karrio's 48.7 (D), and leads in 4 of 7 scored categories. Karrio leads on reliability and security & auth.

### Do Karrio and ShipStation API need an API key?

Both need an API key.

### Can an agent call Karrio and ShipStation API without installing anything?

No hosted endpoint is listed for Karrio. ShipStation API has a hosted endpoint at https://api.shipstation.com/v2.

### Are Karrio and ShipStation API open source?

Karrio is open source (LGPL-3.0 for the server, SDK and modules. Code under `ee/` is under the Karrio Enterprise licence and needs a subscription for production use. The MCP package in `packages/mcp` is Apache-2.0). No open-source release is listed for ShipStation API.


## For agents

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

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