> ## Documentation Index
> Fetch the complete documentation index at: https://terminal49.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Migrate from SeaRates to Terminal49 API
> Map SeaRates tracking API fields, parameters, and errors to their Terminal49 equivalents. Includes webhook setup, carrier coverage, and a migration checklist.
If you have the SeaRates tracking API in production, this page maps it onto Terminal49 field by field, so you can cut over without reverse-engineering our schema.
There is no compatibility shim. You will change your request code and your response parsing. For most integrations that is an afternoon.
## Start in sixty seconds
You do not need to talk to anyone to try this.
Sign up at [app.terminal49.com](https://app.terminal49.com). The free Developer Key tracks up to 10 active containers.
Create a key at [app.terminal49.com/developers/api-keys](https://app.terminal49.com/developers/api-keys).
```bash theme={null}
curl -X POST https://api.terminal49.com/v2/tracking_requests \
-H "Content-Type: application/vnd.api+json" \
-H "Authorization: Token YOUR_API_KEY" \
-d '{
"data": {
"type": "tracking_request",
"attributes": {
"request_number": "YOUR_BOL_NUMBER",
"request_type": "bill_of_lading",
"scac": "MAEU"
}
}
}'
```
The full API key is shown once, right after you create it. Copy it before you navigate away. After that it is masked and cannot be revealed. If you miss it, create a new key and delete the old one.
If you want to test without a live shipment, use the [test tracking numbers](/docs/api-docs/useful-info/test-numbers), which simulate success, failure, and edge-case outcomes.
## The architectural shift
SeaRates gives you one endpoint. You call it with a number, get current state back, and own the schedule, the cache, and the deduplication.
Terminal49 splits this in two. You register a tracking request once. We keep it updated and push changes to your webhook.
Cron every few hours, `GET /tracking`, diff against your cache, dedupe events, then write to your database. Every call spends quota. Freshness is capped by your polling interval.
`POST /tracking_requests` once. Terminal49 polls carriers, terminals, and rail, then POSTs to your endpoint as things change. No cache layer, no dedupe logic.
You can keep polling if you prefer. Point your existing scheduler at `GET /v2/shipments` or `GET /v2/containers`. But webhooks are the reason the API is shaped this way, and terminal data (holds, fees, last free day) changes on a cadence that polling tends to miss.
## Quick comparison
| | SeaRates | Terminal49 |
| ----------------------- | ------------------------------- | ------------------------------------- |
| Tracking model | Poll on demand | Register once, then push or poll |
| Authentication | `api_key` query parameter | `Authorization: Token` header |
| Base URL | `https://tracking.searates.com` | `https://api.terminal49.com/v2` |
| Content type | `application/json` | `application/vnd.api+json` |
| Response format | Custom JSON | JSON:API |
| Webhooks | None | 30+ events, HMAC-signed |
| Carrier identification | `sealine` (SCAC) | `scac`, or omit and use Infer |
| Terminal holds and fees | Not available | Included on the container object |
| Last free day | Not available | Included, with per-source breakdown |
| Rail milestones | Limited | North American Class I and short-line |
| Embeddable widget | Open lookup, any container | Your tracked shipments only (add-on) |
| Getting an API key | Self-serve | Self-serve |
## Authentication
Move the key out of the query string and into a header.
```bash SeaRates theme={null}
curl "https://tracking.searates.com/tracking\
?api_key=YOUR_SEARATES_KEY\
&number=MRKU9465770\
&sealine=MAEU\
&type=CT"
```
```bash Terminal49 theme={null}
curl -X POST https://api.terminal49.com/v2/tracking_requests \
-H "Content-Type: application/vnd.api+json" \
-H "Authorization: Token YOUR_T49_KEY" \
-d '{"data":{"type":"tracking_request","attributes":{
"request_number":"MRKU9465770",
"request_type":"container",
"scac":"MAEU"}}}'
```
Note the `Token` prefix. It is not `Bearer`.
## Request parameter mapping
| SeaRates parameter | Terminal49 equivalent | Notes |
| ------------------ | ------------------------------------------------------------------------------------------- | ------------------------------------------------ |
| `number` | `request_number` | |
| `type=CT` | `request_type: "container"` | |
| `type=BL` | `request_type: "bill_of_lading"` | Master or house BOL |
| `type=BK` | `request_type: "booking_number"` | |
| `sealine` | `scac` | Same SCAC values for most carriers |
| `sealine=auto` | Omit `scac`, or call [Infer Tracking Number](/docs/api-docs/in-depth-guides/auto-detect-carrier) | Returns the predicted SCAC and number type |
| `force_update` | `POST /v2/containers/{id}/refresh` | Forces an immediate pull from all sources |
| `route` | Always included | See [Routing](/docs/api-docs/in-depth-guides/routing) |
| `ais` | Vessel endpoints and container GeoJSON | Not inline on the tracking response |
| `api_key` | `Authorization` header | |
SeaRates accepts a combined `BL_NUMBER/CONTAINER_NUMBER` value in a single `number` field. Terminal49 takes one identifier per tracking request. Track by BOL and we return every container on that bill of lading as related container resources.
## Response field mapping
Terminal49 is JSON:API compliant, so relationships between shipments, containers, ports, and terminals are explicit rather than something you reassemble from ID references.
Use the [`include` parameter](/docs/api-docs/in-depth-guides/including-resources) to sideload related resources in one call instead of chasing IDs.
### Shipment level
| SeaRates | Terminal49 |
| --------------------------------------------- | --------------------------------------------------------- |
| `data.metadata.number` | `shipment.attributes.bill_of_lading_number` |
| `data.metadata.sealine` | `shipment.attributes.shipping_line_scac` |
| `data.metadata.sealine_name` | `shipment.attributes.shipping_line_name` |
| `data.metadata.status` | Derived from container status and milestones |
| `data.route.prepol` | `shipment.attributes.port_of_lading_*` (place of receipt) |
| `data.route.pol` | `shipment.relationships.port_of_lading` |
| `data.route.pod` | `shipment.relationships.port_of_discharge` |
| `data.route.postpod` | `shipment.relationships.destination` (inland) |
| `data.route.pod.predictive_eta` | `shipment.attributes.pod_eta_at` |
| `data.metadata.from_cache`, `cache_expires` | No equivalent. Refresh is managed for you. |
| `data.metadata.api_calls`, `unique_shipments` | No equivalent. Not returned per response. |
### Container level
| SeaRates | Terminal49 |
| ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| `data.containers[].number` | `container.attributes.number` |
| `data.containers[].iso_code` | `container.attributes.equipment_type` + `equipment_length` + `equipment_height` |
| `data.containers[].size_type` | Same three fields above |
| `data.containers[].status` | `container.attributes.current_status` |
| `data.containers[].events[]` | Container timestamps, [transport events](/docs/api-docs/api-reference/containers/get-a-containers-transport-events), and webhook events |
SeaRates returns a single `iso_code` string like `45G1`. Terminal49 splits this into three normalized fields: type (dry, reefer, open top, flat rack, tank, hard top), length (20, 40, 45, 50), and height (standard, high cube). If you were parsing ISO codes yourself, you can delete that code.
### Locations, facilities, and vessels
| SeaRates | Terminal49 |
| ----------------------------------- | ------------------------------------------------------------------------------------------- |
| `data.locations[].name` | `port.attributes.name` |
| `data.locations[].locode` | `port.attributes.code` |
| `data.locations[].lat` / `.lng` | `port.attributes.latitude` / `.longitude` |
| `data.locations[].timezone` | `port.attributes.time_zone` |
| `data.locations[].country_code` | `port.attributes.country_code` |
| `data.facilities[].name` | `terminal.attributes.name` |
| `data.facilities[].smdg_code` | `terminal.attributes.smdg_code` |
| `data.facilities[].bic_code` | `terminal.attributes.bic_code` |
| `data.vessels[].name` | `shipment.attributes.pod_vessel_name` |
| `data.vessels[].imo` | `shipment.attributes.pod_vessel_imo` |
| `data.vessels[].mmsi` | Available via the [Vessels API](/docs/api-docs/api-reference/vessels/get-a-vessel-using-the-imo) |
| `data.vessels[].call_sign`, `.flag` | Not returned |
## Milestone and event mapping
SeaRates returns a flat `events[]` array with an `event_code`. Terminal49 exposes the same milestones as normalized transport events and pushes each one to your webhook.
| SeaRates `event_code` | Milestone | Terminal49 event |
| --------------------- | ----------------------------- | --------------------------------------- |
| `LOAD` | Loaded on vessel at origin | `container.transport.vessel_loaded` |
| `DEPA` | Vessel departed origin | `container.transport.vessel_departed` |
| `ARRI` | Vessel arrived at destination | `container.transport.vessel_arrived` |
| `DISC` | Discharged from vessel | `container.transport.vessel_discharged` |
| `PICK` | Gated out at destination | `container.transport.full_out` |
| `GTIN` | Gated in at origin | `container.transport.full_in` |
| — | Empty picked up at origin | `container.transport.empty_out` |
| — | Empty returned at destination | `container.transport.empty_in` |
Terminal49 also emits milestones SeaRates has no equivalent for:
* **Vessel berthed:** `container.transport.vessel_berthed`
* **Available for pickup:** `container.transport.available` and `.not_available`
* **Transshipment:** arrived, discharged, loaded, departed
* **Feeder vessel and barge:** arrived, discharged, loaded, departed
* **Rail:** loaded, departed, arrived, unloaded, plus `arrived_at_inland_destination`
See the full [event catalog](/docs/api-docs/webhooks/event-catalog).
### Registering a webhook
```bash theme={null}
curl -X POST https://api.terminal49.com/v2/webhooks \
-H "Content-Type: application/vnd.api+json" \
-H "Authorization: Token YOUR_API_KEY" \
-d '{
"data": {
"type": "webhook",
"attributes": {
"url": "https://your-endpoint.example.com/t49",
"active": true,
"events": [
"container.transport.vessel_discharged",
"container.transport.available",
"container.pickup_lfd.changed"
]
}
}
}'
```
Payloads are HMAC-signed. See [webhook setup](/docs/api-docs/in-depth-guides/webhooks) for signature verification, and [List webhook IPs](/docs/api-docs/api-reference/webhooks/list-webhook-ips) if your firewall restricts inbound traffic.
## What you gain
This is the part worth reading even if the rest is mechanical. Terminal49 integrates with terminals directly, not only carriers, so the container object carries operational data that has no SeaRates equivalent.
### Holds
`holds_at_pod_terminal` is an array of active holds blocking pickup:
```json theme={null}
{
"holds_at_pod_terminal": [
{ "name": "customs", "status": "hold", "description": "CBP HOLD" },
{ "name": "freight", "status": "hold", "description": null }
]
}
```
Hold names are `freight`, `customs`, `USDA`, `VACIS`, `TMF`, and `other`. Status is `hold` or `pending`. When a hold clears, the object is removed from the array. There is no released state.
Hold names are case-sensitive. `USDA`, `VACIS`, and `TMF` are uppercase; `freight`, `customs`, and `other` are lowercase. Match exactly.
### Fees
`fees_at_pod_terminal` carries type, amount, and currency:
```json theme={null}
{
"fees_at_pod_terminal": [
{ "type": "demurrage", "amount": 850.00, "currency_code": "USD" },
{ "type": "exam", "amount": 450.00, "currency_code": "USD" }
]
}
```
Fee types are `demurrage`, `extended_dwell_time`, `exam`, `total`, and `other`.
Some terminals report a `total` line item alongside individual fees. Filter it out before summing or you will double-count.
### Last free day
`pickup_lfd` is a coalesced value that follows a fixed source priority: shipping line, then terminal, then rail. It does not pick the earliest date. The individual sources are available separately on `import_deadlines`:
* `pickup_lfd_line`: the shipping line's LFD (per diem deadline)
* `pickup_lfd_terminal`: the terminal's LFD (demurrage deadline)
* `pickup_lfd_rail`: the rail carrier's LFD at the inland destination
Each has its own webhook event, so you can alert on whichever source your operation cares about.
### Release readiness
Two fields answer "can I pick this up?" `available_for_pickup` and the holds array:
```javascript theme={null}
function isReadyForPickup(container) {
const { available_for_pickup, holds_at_pod_terminal } = container.attributes;
const hasActiveHolds = holds_at_pod_terminal.some(h => h.status === 'hold');
return available_for_pickup === true && !hasActiveHolds;
}
```
Full detail in [Holds, Fees, and Release Readiness](/docs/api-docs/in-depth-guides/holds-and-fees).
Holds, fees, LFD, and availability come back on the container object wherever the terminal is a supported source. They are not a paid add-on and they do not require a sales conversation. See [Entitlements](/docs/api-docs/useful-info/entitlements) for the features that do require account enablement. Rail LFD and the embeddable widget are the main ones.
## Replacing the SeaRates widget
If you embedded the SeaRates tracking widget on your own website, read this before you swap in ours. They behave differently and the difference matters.
**The SeaRates widget is an open lookup.** Any visitor types any container number and gets a result, whether or not that shipment has anything to do with you.
**The Terminal49 widget is a customer portal.** It resolves only shipments and containers already tracked in your Terminal49 account. A visitor entering a container you are not tracking gets nothing back.
For most freight forwarders this is the behaviour you actually want. Your customers see their shipments, and you are not running a free public lookup service on your own domain. But if you were relying on open lookup, this is a real change and you should plan for it.
The embed is two lines:
```html theme={null}
```
Your customers can search by master bill of lading, container number, or any reference number you have tagged a shipment with. We suggest a dedicated page at `yourcompany.com/track`.
The widget is an add-on, priced against container volume, and the publishable key comes from [support@terminal49.com](mailto:support@terminal49.com) rather than the developer portal. Email us and we will get you set up.
If you want a map rather than a lookup form, see the [Map Embed Guide](/docs/api-docs/in-depth-guides/terminal49-map). Same publishable key, renders live vessel positions and routes.
## Gotchas that will bite you
SeaRates returns local time as `YYYY-MM-DD HH:MM:SS`. Terminal49 stores event timestamps in UTC and returns the matching IANA timezone alongside. Convert for display rather than assuming local time. See [Event Timestamps](/docs/api-docs/in-depth-guides/event-timestamps).
`POST /tracking_requests` returns immediately with a pending status. The shipment appears once the carrier responds. Subscribe to `tracking_request.succeeded` and `tracking_request.failed` rather than expecting shipment data in the creation response. A request may also land in `awaiting_manifest` if the carrier has not manifested the shipment yet, and we retry automatically. See [Tracking Request Lifecycle](/docs/api-docs/in-depth-guides/tracking-request-lifecycle).
`holds_at_pod_terminal: []` and `fees_at_pod_terminal: []` mean no active holds or fees. This is the common case. Do not treat it as missing data.
It means the terminal reported the fee type but has not posted an amount yet. Common for demurrage in the first day or two after discharge.
Relationships are ID references into an `included` array. Use a JSON:API client library, or use `include` to sideload exactly what you need. Parsing raw JSON works but you will write more code than you expect.
Terminal changes (fees, holds, LFD, appointment, availability) arrive on `container.updated` with a `changeset` showing old value first, new value second. Use it instead of diffing state yourself.
## Error handling
SeaRates returns HTTP 200 for both success and failure, with the error in the response envelope. Terminal49 uses standard HTTP status codes. Replace envelope checks and message-string matching with status-code checks.
| Status | Meaning |
| ------ | -------------------------------------------------------------------------- |
| 400 | Malformed request or failed validation |
| 401 | Missing or invalid API key |
| 403 | Key lacks permission, or the feature is not enabled on your plan |
| 404 | Resource does not exist |
| 422 | Valid syntax, rejected content. For example, a malformed container number |
| 429 | Rate limited. See [Rate Limiting](/docs/api-docs/in-depth-guides/rate-limiting) |
| 5xx | Terminal49 or an upstream carrier or terminal is unavailable |
Rough equivalence for the SeaRates errors you are handling today:
| SeaRates error | Terminal49 |
| ---------------------------------------------------------- | ----------------------------------------------------------------------- |
| `API_KEY_WRONG`, `API_KEY_EXPIRED` | HTTP 401 |
| `API_KEY_ACCESS_DENIED` | HTTP 403 |
| `API_KEY_LIMIT_REACHED`, `API_KEY_RATE_LIMIT` | HTTP 429 |
| `WRONG_PARAMETERS`, `WRONG_NUMBER`, `WRONG_TYPE` | HTTP 400 or 422 |
| `WRONG_SEALINE`, `SEALINE_NOT_SUPPORTED` | HTTP 422 |
| `SEALINE_HASNT_PROVIDE_INFO`, `NO_CONTAINERS`, `NO_EVENTS` | `tracking_request.failed`, or `awaiting_manifest` if not yet manifested |
| `AUTO_CANT_DETECT_SEALINE` | Infer endpoint returns no prediction |
| `SEALINE_TEMPORARY_DISABLED`, `SEALINE_NO_RESPONSE` | Not surfaced. We retry internally. |
The [TypeScript SDK](/docs/sdk/introduction) maps these to typed errors (`AuthenticationError`, `ValidationError`, `RateLimitError`, `UpstreamError`, `FeatureNotEnabledError`) and retries rate-limit and server errors automatically with exponential backoff.
## Where we are narrower than SeaRates
Worth knowing before you commit.
**Carrier count.** Terminal49 integrates directly with 36 ocean carriers, plus 2 more enabled on request, as of 14 August 2026. SeaRates lists substantially more. Ours are direct integrations covering the lines that move volume into North America, and each is normalized into one schema. Check your carrier mix against the [ocean carrier list](/docs/coverage/ocean-carriers) before cutover, and read the known issues section there. We publish the per-carrier field gaps.
**Terminal data is North America.** Holds, fees, LFD, and availability come from direct terminal integrations concentrated in the US and Canada, with European ports expanding. Ocean milestones work globally; terminal-level operational data does not yet.
**No air, parcel, or road tracking.** If your integration covers those modes, this migration handles only the ocean portion.
**No freight rates or sailing schedules.** We do not offer a rate calculator, rate index, or schedule search.
**Some fields are source-dependent.** Seal number, container weight, and departure or arrival events vary by carrier. The [field availability reference](/docs/coverage/fields) says which fields are always present and which depend on the carrier, terminal, or journey.
## Migration checklist
Everyone does the base path. Then pick a branch.
### Base path
Self-serve at [app.terminal49.com/developers/api-keys](https://app.terminal49.com/developers/api-keys). Copy it immediately, it is shown once.
Move the key from a query parameter to `Authorization: Token`. Note the `Token` prefix.
Compare your SeaRates `sealine` values against the [carrier list](/docs/coverage/ocean-carriers). Flag anything missing before you cut over.
One `POST /tracking_requests` per BOL, booking, or container, replacing the per-request lookup.
Tracking requests start pending. Handle `succeeded`, `failed`, and `awaiting_manifest` rather than expecting data on creation.
JSON:API structure, split equipment fields, UTC timestamps with a separate timezone.
Replace envelope checks with HTTP status codes.
Submit tracking requests for everything currently in transit. Send us the list if it is large and we will load it.
Holds, fees, and LFD are the reason to do this properly rather than porting like for like.
### Then pick one
Accept our POST payloads at a public URL.
Subscribe only to events you act on.
Reject any payload whose signature does not match.
Only needed if your firewall restricts inbound traffic.
Confirm end-to-end before going live.
Remove your dedupe layer along with it.
See [webhook best practices](/docs/api-docs/webhooks/best-practices) for retries and idempotency.
Keep the tracking request ID and shipment ID from the creation response.
Point it at `GET /v2/shipments` or `GET /v2/containers`.
No change to how often you poll.
Skipped: endpoint setup, signature verification, IP whitelisting, delivery testing.
Terminal data changes on a cadence polling tends to miss. If you only adopt webhooks for one thing, make it `container.updated` and `container.pickup_lfd.changed`.
## Migrate with an AI coding agent
If you use Cursor, Claude Code, Windsurf, Copilot, or another AI coding assistant, hand it the prompt below. It is written to run a **side-by-side migration**: the agent stands up a Terminal49 client next to your existing SeaRates code, shadows every SeaRates call with a Terminal49 call, diffs the responses, and only cuts over once parity is proven.
Point your agent at this page as context (paste the URL or add it as a doc source). The prompt references the mappings above, so the more of this page the agent can see, the better it does.
1. Open your repo in your AI coding tool.
2. Add this page as a documentation source, or paste its URL into the chat.
3. Copy the prompt below into a new chat and send it.
4. Answer the agent's discovery questions (SeaRates client location, env var names, carrier mix).
5. Review each PR the agent opens. It should ship in small, reviewable steps: client, shadow, parity harness, cutover, cleanup.
* A `Terminal49Client` alongside your existing `SeaRatesClient`, sharing the same interface where possible.
* A shadow-mode wrapper that calls both providers and logs response diffs without changing behavior.
* A parity report per shipment: matched fields, diverged fields, and Terminal49-only fields (holds, fees, LFD).
* A feature-flagged cutover: route reads to Terminal49, keep SeaRates as fallback until you flip the flag off.
* A webhook receiver with HMAC verification, or a polling scheduler, depending on which path you pick.
* A cleanup PR that removes SeaRates code, env vars, dependencies, and dedupe logic.
### The prompt
Copy this into your agent. Replace the bracketed placeholders in the **Repo context** block before sending.
```markdown Terminal49 migration agent prompt expandable icon=robot wrap theme={null}
You are migrating this codebase from the SeaRates tracking API to the Terminal49 API,
side by side. Terminal49's authoritative migration guide is at
https://terminal49.com/docs/api-docs/getting-started/migrate-from-searates. Use it as
the source of truth for field mappings, event names, error codes, and behavior differences.
# Repo context (fill this in before running)
- SeaRates client lives at: [path/to/searates/client.ts]
- SeaRates is called from: [list the call sites or "find them"]
- Language and framework: [e.g. TypeScript + Node, Python + FastAPI, Ruby on Rails]
- Storage for tracking state: [e.g. Postgres table `shipments`]
- Current polling schedule: [e.g. cron every 2h via BullMQ]
- Carrier mix (SCACs we track most): [e.g. MAEU, MSCU, CMDU, HLCU, ONEY]
- Deployment target: [e.g. AWS ECS, Vercel, Fly.io]
- Secret store: [e.g. AWS Secrets Manager, `.env`, Doppler]
# Rules
1. Do not delete SeaRates code until the cleanup step. Migration is side by side.
2. Ship in small PRs. Each PR must build, pass tests, and be independently revertable.
3. Never invent Terminal49 fields, endpoints, or event names. If the guide does not
confirm a mapping, ask me. Do not guess.
4. Terminal49 uses `Authorization: Token ` (not `Bearer`) and content type
`application/vnd.api+json`. Get this right on the first request.
5. Terminal49 is asynchronous. `POST /tracking_requests` returns pending. Data arrives
via `tracking_request.succeeded`, `tracking_request.failed`, or `awaiting_manifest`
webhooks, or by polling `GET /v2/shipments`. Do not expect shipment data on creation.
6. Timestamps are UTC with a separate IANA `time_zone` field. Do not assume local time.
7. `holds_at_pod_terminal: []` and `fees_at_pod_terminal: []` are the normal state,
not missing data. A fee `amount` of 0 is valid.
8. On `container.updated`, prefer the `changeset` over diffing state yourself.
# Plan (execute in order, one PR per step)
## PR 1 — Discovery and interface
- Grep the repo for every SeaRates call site. List them in the PR description.
- Extract the SeaRates client's public surface into an interface
(`TrackingProvider` with methods like `track(number, type, sealine)`,
`getShipment(id)`, `refresh(id)`).
- Make the existing SeaRates client implement it. No behavior change.
## PR 2 — Terminal49 client
- Add a `Terminal49Client` implementing the same `TrackingProvider` interface.
- Auth via `T49_API_KEY` env var, header `Authorization: Token ${key}`.
- Base URL `https://api.terminal49.com/v2`, content type `application/vnd.api+json`.
- Implement:
- `createTrackingRequest({ request_number, request_type, scac })` returning the
tracking request ID.
- `getShipment(id, { include: 'containers,port_of_lading,port_of_discharge,...' })`.
- `getContainer(id)`.
- `refreshContainer(id)` mapping to `POST /v2/containers/{id}/refresh`.
- Normalize responses to the same shape SeaRates callers expect today, using the field
mapping from the guide. Split `iso_code` into `equipment_type`, `equipment_length`,
`equipment_height`. Convert timestamps to UTC + `time_zone`.
- Map errors to typed classes: `AuthenticationError` (401), `AuthorizationError` (403),
`ValidationError` (400/422), `RateLimitError` (429), `UpstreamError` (5xx),
`FeatureNotEnabledError` (403 + feature flag response).
- Add unit tests using recorded fixtures. Do not hit the live API in tests.
## PR 3 — Shadow mode
- Add a `ShadowProvider` that wraps both clients. On every read:
- Call SeaRates as the primary. Return its response.
- Fire-and-forget a Terminal49 call for the same identifier.
- Log a structured diff: matched fields, diverged fields, T49-only fields.
- Gate with env var `TRACKING_SHADOW_MODE=true`. Off by default.
- Add a parity report script that aggregates shadow logs by SCAC and field.
- Do NOT change what callers see. This step is observation only.
## PR 4 — Backfill script
- Write a one-shot script that reads all active shipments from our database and calls
`POST /tracking_requests` for each (one per BOL, booking, or container).
- Store the returned `tracking_request.id` and eventual `shipment.id` on our records.
- Rate-limit to respect Terminal49's limits (handle 429 with exponential backoff).
- Idempotent: safe to re-run. Skip rows already backfilled.
## PR 5 — Webhook receiver (only if we picked the webhook path)
- Add `POST /webhooks/terminal49` endpoint.
- Verify HMAC signature using the shared secret from `T49_WEBHOOK_SECRET`. Reject on
mismatch with 401.
- Handle these events at minimum:
- `tracking_request.succeeded`, `tracking_request.failed`, `tracking_request.awaiting_manifest`
- `container.transport.vessel_discharged`, `container.transport.available`,
`container.transport.full_out`
- `container.updated` (use the `changeset`, do not diff)
- `container.pickup_lfd.changed`
- Persist events idempotently keyed by event ID.
- Register the webhook via `POST /v2/webhooks` from a bootstrap script, subscribing
only to events we handle.
- If our firewall restricts inbound traffic, whitelist Terminal49 IPs from
`GET /v2/webhooks/ips`.
## PR 6 — Cutover behind a flag
- Add feature flag `TRACKING_PROVIDER` with values `searates` (default) and `terminal49`.
- Route all reads through the flag. SeaRates stays available as a fallback for one
release cycle.
- Flip staging to `terminal49`, verify parity report is clean, then flip production.
## PR 7 — Cleanup
- Delete `SeaRatesClient`, its tests, its env vars, its dedupe cache, and any
ISO-code parsing helpers Terminal49 makes redundant.
- Remove the shadow provider and the feature flag.
- Update README and any runbooks. Note the new webhook endpoint if applicable.
# Definition of done
- All SeaRates call sites now go through Terminal49.
- Webhook (or polling) is live in production.
- Parity report shows no unexplained divergences for our top 10 SCACs.
- Holds, fees, and LFD are exposed to whichever downstream system needs them
(dashboard, alerts, customer emails). Do not migrate without wiring these up. They
are the reason to do this properly.
- SeaRates dependency, env vars, and dead code are gone from the repo.
# Ask me before you
- Choose between the webhook path and the polling path. Default to webhooks unless our
infra makes an inbound HTTPS endpoint hard.
- Change the shape of any function SeaRates callers use today. Prefer a normalization
layer inside the Terminal49 client.
- Add a new dependency. Prefer stdlib and what is already in the repo.
- Touch anything outside the tracking integration.
Start with PR 1. Post the list of SeaRates call sites and the proposed
`TrackingProvider` interface, and wait for my review before writing PR 2.
```
The prompt is deliberately opinionated on side-by-side migration and small PRs. If your team prefers a big-bang cutover or a different branching model, edit the **Plan** section before sending it to your agent.
## Getting help
Send us your list of active container and bill of lading numbers and we will load them rather than making you script the backfill.
If something in this mapping is wrong or incomplete, tell us. We would rather fix the page than have you work around it.
Every endpoint, with request and response schemas
Typed client with retries and pagination built in
Carriers, terminals, rail, and field availability
Simulate success, failure, and edge cases