Freight emissions API comparison 2026 — EcoFreight vs Climatiq vs Cloverly vs BigMile

Five APIs come up almost every time a buyer asks me how to pick a freight emissions service: Climatiq, Cloverly, BigMile, Pledge, and the one I work on, EcoFreight. The methodology layer is almost identical across them — GLEC Framework v3.2, mostly ISO 14083 aligned, the usual well-to-wake split. The real differences are in pricing transparency, vertical depth, primary-data ingestion, and what each one quietly excludes. I want to lay those out without pretending I am neutral.

Disclosure up front. I run the engineering side of EcoFreight — see my author page if you want background. I have integrated against four of the five APIs here (Climatiq, Cloverly, BigMile, Pledge) and read enough of the Searoutes documentation for an honourable-mention sea-routing section. I am biased. What follows is the comparison I would have wanted as a buyer — honest about who is better at what, with the disclosure visible and not buried in a footer. If you want the head-to-head pages without the full essay, the comparison index is the shortcut.

An honest comparison table

The hardest part of writing this was deciding how to handle the cells where a competitor genuinely beats us. The decision was to write them down. There are a few.

A few notes before anyone holds me to a number. Latency figures are my own — London laptop, April 2026, around thirty calls each, simple multimodal payloads. They will not match a vendor's published p50 to the millisecond and that is fine; what matters is the order of magnitude. Climatiq is fast on factor lookup but slower on a full shipment because it does not route — you have to bring distances. BigMile is slowest on a single call because its strength is bulk shipper ingestion. Searoutes is closest to us on raw routing speed because that is what they were built for.

Where each one is genuinely best

Climatiq has the largest factor catalogue, and it is not close. If you need an emissions number for a category outside transport — purchased goods, electricity, business travel, the long tail of Scope 3 — Climatiq is the one. Their public pricing tier is also genuinely public, which is rare. If you are doing whole-of-company GHG accounting and freight is one of fifteen categories, start with Climatiq.

Cloverly has the best offset-marketplace integration of anyone here. Calculate emissions and retire credits in one flow — that pattern is theirs, and they execute it well. Their offset registry coverage (Verra, Gold Standard, Climate Action Reserve, others) is broader than any other emissions API. We do not do offsets, deliberately, and Cloverly is the vendor I refer people to when the question comes up.

BigMile has the deepest ISO 14083 ingestion tooling for shippers I have seen. If you are a manufacturer or retailer with primary fuel-burn data from contracted carriers and you want to upload it, allocate it across shipments, and produce CSRD-grade Category 4 disclosures, BigMile is built for exactly that workflow. The trade-off is that the API is shaped for periodic bulk reconciliation, not high-volume per-shipment lookup. For a TMS pattern, BigMile is the wrong shape.

Pledge has the best forwarder-specific user interface of any vendor here. The product is built around how a freight forwarder books, quotes, and rebills emissions — AWB-level for air, BL-level for ocean, with sustainability statements that match what their customers want on the invoice. Pricing is opaque, which is a downside, but the vertical fit is real.

Searoutes has the best ocean and intermodal routing engine of anyone in this set. The honourable mention because they sell routing first and emissions second — but the routing they produce is good enough that several of us in the industry use it as the reference for what an accurate sea distance should look like. More on my Searoutes blind spot below.

EcoFreight, which I work on, is — I think — the only one in this set with all four at once: a public free tier (1,000 req/month, no card), public Growth pricing without a sales call, a public OpenAPI spec at /docs, and a p50 latency around 42 ms (p95 around 174 ms) on standard shipments. None of those individually is a moat. But together they are what makes a developer's first hour easy, and the first hour matters more than people give it credit for. I have walked one such first hour end-to-end in the engine walk-through.

What is genuinely the same

The thing that surprised me when I started this comparison is how much overlap there is on the substance. Every API in this list:

• Aligns to GLEC Framework v3.2 for the freight transport factor sourcing.
• Implements ISO 14083:2023 for activity allocation, distance methods, and the well-to-wake / tank-to-wake / well-to-tank split.
• Returns WTW, TTW, and WTT components, in g CO2e per tonne-kilometre and absolute kilograms, in a roughly REST-shaped JSON response.
• Updates emission factors annually when Smart Freight Centre publishes new GLEC tables and ad-hoc when IMO MEPC sessions adjust marine factor sets.

So the factor itself, for a generic articulated truck on a generic European motorway with a generic load factor, will come out within 3-5% across every API here. The methodology convergence is one of the genuinely good things that has happened in this space over the past four years. Vendors differentiate now on the data they bring, the workflow they support, and the developer experience around the call — not on the underlying physics.

The questions to actually ask a vendor

I have sat on the customer side of a few of these evaluations. The questions that separate the serious vendors from the marketing surface tend to be these five.

What is the default ISO 14083 data quality tier in a response, and when does it fall back? Good answer: the response names a tier (1 through 5), the calculation defaults to the highest tier the inputs allow, and any fallback is logged with a reason. Bad answer: a vague "we use the best available data" with no per-response tier flag.

Which lanes have primary data, and which fall back to GLEC defaults? Every vendor advertises primary data. The honest version is that primary data is patchy — strong on the lanes the vendor has direct telematics or AIS feeds for, defaults elsewhere. A vendor who can show you a lane-by-lane coverage table is more honest than one who cannot.

How often do emission factors refresh, and how is that documented? Smart Freight Centre updates GLEC roughly annually; IMO updates marine factors more irregularly. Good answer: a changelog with version numbers and dates. Bad answer: "we keep them current."

How long do calculation records stay queryable for audit? CSRD assurance requires reproducible calculations. If a vendor cannot tell you the retention period or rehydrate a calculation_id from two years ago with the same inputs and factor set, the audit story will fall apart at the wrong moment.

What is the SLA, and what is excluded? Uptime numbers are easy to advertise. The exclusions — planned maintenance windows, degraded-mode acceptance, force majeure — are where the actual commitment lives. Read the exclusions, not the headline 99.9%.

What EcoFreight does not do, yet

To stay honest, here is what we do not have that some of the competitors do.

SDKs in your language. Python and Node SDKs are on the roadmap, target end of Q3 2026. Today the integration is REST against the OpenAPI spec — it works, but it is not as smooth as Climatiq's first-party SDKs.

A batch endpoint. You call us per shipment. A bulk endpoint that takes a CSV or NDJSON payload and returns calculations in one round-trip is planned for Q3 2026. For monthly batch reconciliation of 100,000+ shipments, BigMile is the better fit today.

Embedded offset marketplace. No plans. Carbon credit purchase is not in scope for us — we measure emissions, offset providers are a separate question. The people who do offsets well — Cloverly, Pachama, a few others — do it as their whole product, not as an add-on. We refer customers there.

Forwarder-specific UI primitives. Pledge has AWB-level and BL-level views tightly coupled to the forwarder workflow. We have the underlying calculation, not the forwarder-specific presentation layer. If you need that out of the box, Pledge will save you weeks.

One unhedged opinion

If you are going to spend more than $500 a month on a freight emissions API, integration ergonomics matter more than factor freshness. The factors converge to within roughly 5% across all of these vendors; the API responses do not converge on how easy they are to plug into your TMS. A response that names the data quality tier, returns a stable calculation_id, exposes a clean WTW/TTW/WTT split, and includes a request_id you can quote at support — that is what saves engineering time, and engineering time at $500-plus per month swamps the difference between a 65 g/tkm factor and a 67 g/tkm factor. People will sell you on factor freshness because it is easier to put on a comparison sheet than developer experience. Do not be fooled by the easy thing.

An acknowledged gap

I have not personally integrated against Searoutes in production. I have read their methodology, called their endpoints from Postman during this comparison, and talked to two engineers who use them — but I have not shipped code that depends on them at scale. When I cross-checked their activity number for a Shanghai-to-Rotterdam container shipment against our engine, theirs came back about 4% lower. I do not yet know whether that is a routing difference, a different default load factor, or a true emission-factor delta. Take my Searoutes section with that grain of salt.

A short decision tree

• If your TMS supports webhooks and you want per-shipment numbers in real time on your dashboard, EcoFreight or Climatiq.
• If you have primary fuel-burn data from contracted carriers and want CSRD-grade Category 4 ingestion, BigMile.
• If you are a freight forwarder and need AWB-level or BL-level emissions on invoices, Pledge.
• If you only need high-fidelity ocean and intermodal routing with emissions as a derived output, Searoutes.
• If you want to offer carbon-neutral checkout with one API call that calculates and retires, Cloverly.
• If you need emissions across all of Scope 3 (not just freight), Climatiq.
• If you want the cheapest path from "first read the docs" to "first emission number in production" and a developer-friendly free tier with public pricing, EcoFreight.

Close

The space is healthier than it was. Four years ago an emissions API was an opaque box that returned a number with no factor disclosure, no data quality tier, and no audit trail. Today every vendor in this list will tell you which GLEC version, which tier, which scope. That is the floor now, and the floor being raised is good for everyone — including buyers, who can finally compare apples to apples.

If you want to try our version, the multimodal calculator runs against the same engine the API uses, and the API documentation is public — no sales conversation needed to read the spec or call the free tier. For deeper reading: when to pick SDK over raw REST, a 3PL's migration from quarterly Excel to per-shipment API, and the Scope 3 Category 4 CDP guide if your endpoint is a sustainability report rather than a TMS. If after reading this you decide another vendor is a better fit for your shape of problem, that is fine. The worst outcome is picking the wrong API and discovering it nine months in; the best is picking the right one the first time, which is mostly what this post was trying to help with.

Vendor URLs cited inline. Latency numbers are my own measurements from April 2026, London, simple multimodal shipments — your numbers will vary by geography, payload shape, and time of day. Where I have credited a competitor as best at something, that is based on integrations I have run or, in the Searoutes case, on documentation review and conversations with engineers who use them. If a vendor reads this and disagrees with a characterisation, the inbox is open and corrections welcome.