Spree Legacy API v2

Before writing code

Fetch live docs:

1. Fetch https://github.com/spree/spree_legacy_api_v2 (README) for the current install and supported Spree versions.
2. The historical v2 docs may live at https://api.spreecommerce.org/ — verify what's still hosted.
3. Compare with the v3 reference at https://spreecommerce.org/docs/api-reference to plan migration.
4. Check the Spree release notes — v2 endpoints can be removed without notice in major upgrades.
5. Inspect the gem's controllers under app/controllers/spree/api/v2/.

Conceptual Architecture

What Was v2

API v2 was the canonical Spree API across v4.x and v5.0–5.3. Two surfaces:

Style: JSON:API 1.0 — { data: { id, type, attributes, relationships } } envelope.

v2 Status in v5+

• Bundled in spree umbrella through v5.3.
• Extracted to the spree_legacy_api_v2 gem from v5.4+ — not in the umbrella by default.
• Deprecated; will eventually be removed. Treat any new development as v3-first.

Why It Existed (and Still Matters)

Apps built between 2020 and 2025 use v2. The gem keeps those clients working while you migrate to v3.

Adding the Gem in v5.4+

# Gemfile
gem 'spree_legacy_api_v2'

# Then
bundle install
bin/rails g spree_legacy_api_v2:install   # if a generator is shipped — verify

Mounts /api/v2/storefront/* and /api/v2/platform/*.

Auth — Storefront API v2

Password grant (verify current OAuth2 grant types accepted):

POST /spree_oauth/token
Content-Type: application/x-www-form-urlencoded

grant_type=password&username=user@example.com&password=...

Response:

{ "access_token": "...", "token_type": "Bearer", "expires_in": 7200, "refresh_token": "..." }

For guest carts, use X-Spree-Order-Token header. Some v2 endpoints accept anonymous access with just an order token.

Auth — Platform API v2

Client credentials grant with admin scope:

POST /spree_oauth/token
Content-Type: application/x-www-form-urlencoded

grant_type=client_credentials&client_id=...&client_secret=...&scope=admin

Doorkeeper applications are managed in admin → Settings → OAuth Applications.

JSON:API Envelope

{
  "data": {
    "id": "1",
    "type": "product",
    "attributes": {
      "name": "Classic Tee",
      "description": "100% cotton",
      "created-at": "2025-04-15T10:00:00Z",
      "price": "19.99"
    },
    "relationships": {
      "variants": { "data": [{ "id": "2", "type": "variant" }] },
      "default-variant": { "data": { "id": "2", "type": "variant" } }
    }
  },
  "included": [
    { "id": "2", "type": "variant", "attributes": { ... } }
  ]
}

Compare with v3's flat JSON — different fundamental shape.

Sparse Fieldsets & Includes

GET /api/v2/storefront/products?include=default_variant,images&fields[product]=name,price

include pulls related resources into included; fields[type] filters attributes per type.

Pagination

JSON:API style:

GET /api/v2/storefront/products?page=2&per_page=25

Returns links.first, links.next, links.prev, links.last + meta.total_count, meta.total_pages.

Filtering

GET /api/v2/platform/orders?filter[state]=complete&filter[created_at_gteq]=2025-01-01

Filters use Ransack syntax (_eq, _gteq, _lteq, _in, _not_eq, etc.). Powerful but verbose.

Errors

{
  "errors": [
    {
      "status": "422",
      "code": "invalid_email",
      "title": "Invalid email",
      "detail": "Email is not valid",
      "source": { "pointer": "/data/attributes/email" }
    }
  ]
}

Implementation Guidance

Decision: v2 or v3 for New Work?

Always v3 unless:

• You're integrating with an existing v2 partner that can't migrate yet
• You're shipping a patch for an existing v2-only client
• The v3 endpoint coverage is missing for your use case (rare in v5.4+)

Running v2 and v3 Side-By-Side

In v5.4+, gem-installing spree_legacy_api_v2 mounts v2 endpoints without conflict — v3 lives at /api/v3/, v2 at /api/v2/. Same Doorkeeper applications can serve both.

Authenticating a Storefront v2 Client

require 'net/http'
require 'json'

# Get a token
res = Net::HTTP.post(
  URI('https://your-spree.com/spree_oauth/token'),
  { grant_type: 'password', username: email, password: pwd }.to_query,
  'Content-Type' => 'application/x-www-form-urlencoded'
)
token = JSON.parse(res.body)['access_token']

# Use it
req = Net::HTTP::Get.new('/api/v2/storefront/account')
req['Authorization'] = "Bearer #{token}"

Authenticating a Platform v2 Client

res = Net::HTTP.post(
  URI('https://your-spree.com/spree_oauth/token'),
  { grant_type: 'client_credentials',
    client_id: ENV['CLIENT_ID'],
    client_secret: ENV['CLIENT_SECRET'],
    scope: 'admin' }.to_query,
  'Content-Type' => 'application/x-www-form-urlencoded'
)
admin_token = JSON.parse(res.body)['access_token']

Migrating From v2 to v3

Field-level changes:

Migration strategy:

1. Stand up v3 endpoints in parallel
2. Update one client surface at a time (start with read-only paths)
3. Sunset v2 after observability shows no calls for N weeks
4. Eventually remove the gem

Common Pitfalls

• Forgetting to install spree_legacy_api_v2 in v5.4+ — your v2 clients silently 404.
• Mixing v2 and v3 client code in the same component — different envelope shapes, hard to maintain.
• Sparse fieldsets without include — relationships still show as null references; you need to also include them.
• Ransack filters expose more than you want — by default, all model columns are filterable. Configure ransackable_attributes per model in production.
• Password grant exposing user credentials — only the storefront uses it; never use password grant in third-party integrations.
• Token refresh not handled — v2 tokens expire; implement refresh on 401.

Always cross-check the legacy gem's README for the Spree version it currently supports — the gem can lag the umbrella by minor releases.