How do I verify a Chinese valve manufacturer’s API licence?

Search the licence number or company name in the API Composite List published by the American Petroleum Institute and read the expiry date and scope, not only the status flag. A certificate image on a website is not enough on its own.

Why do you not name the factories on the website?

The panel is quoted as a group: one RFQ goes to several licensed factories and we compare the offers. Naming a factory, or listing its licence set and expiry year, would be enough to find it in the public registry and go around us. The quotation names the manufacturer and its licence number, so you can check the licence before you place the order.

How many factories are on the panel?

The table above states, per API specification, how many signed panel factories hold that licence in force. Every factory on the panel has signed an agreement with us that includes no-bypass terms. The counts are published; the factory list is not.

Wenzhou valve manufacturers, checked licence by licence

Manufacturers · factory panel

Wenzhou is one of China’s largest valve clusters, and the API Composite List lists dozens of licensed factories there. A “Top 10” list will not tell you which licences are still in force. We check every panel factory by the expiry date in the registry, send one RFQ to several of them and name the manufacturer, with its licence number, in the quotation. This page reports the panel as counts per API specification, never factory by factory.

Factory panel

Licence counts read from the API Composite List on 8 Nov 2026; next check 8 Feb 2027.
API specification	Signed panel factories with the licence in force	What the licence covers
API 6D	4	Ball, gate, plug and check pipeline valves
API 609	3	Butterfly valves, Category A and Category B
API 608	2	Metal ball valves, flanged, threaded and welding ends

A licence counts only while its expiry date is after the registry check; the registry’s “Active” flag is never used on its own. Every factory counted has a signed panel agreement with us. Factory names and licence numbers are given in your quotation, with the link to verify them in the API Composite List. Read how we check a licence.

How each panel factory is checked

We read the licence status, scope and expiry date from the API Composite List and record the date of the check. The registry’s “Active” flag is not enough on its own: in our November 2026 check, some Wenzhou entries were still marked Active after their expiry date. A factory stays on the panel only while its licence is in force, and the panel is re-checked every quarter.

Other certificates a factory states, such as API 607 fire tests or ISO 15848 emission tests, count only after we have reviewed the original certificate.

Counts, not rows

A per-factory row would show a licence set and an expiry year, and that combination narrows to a handful of registry entries. Anyone could then look the factory up and buy around us. So the panel is published as one number per API specification: how many signed panel factories held that licence in force when we last checked.

Every factory counted here has signed a panel agreement with us, including no-bypass terms, and quotes through us. The count only falls when a licence passes its expiry date or a factory leaves the panel.

Why the panel is anonymous

Factory names and licence numbers are not published on this site. Your quotation names the manufacturer of the valve you are quoted, its API licence number and the registry link, so you can verify it before you order. Several factories quote the same RFQ, and we compare their offers against your datasheet, line by line.

Manufacturers by product

Frequently asked questions

How do I verify a Chinese valve manufacturer’s API licence?: Search the licence number or company name in the API Composite List published by the American Petroleum Institute and read the expiry date and scope, not only the status flag. A certificate image on a website is not enough on its own.
Why do you not name the factories on the website?: The panel is quoted as a group: one RFQ goes to several licensed factories and we compare the offers. Naming a factory, or listing its licence set and expiry year, would be enough to find it in the public registry and go around us. The quotation names the manufacturer and its licence number, so you can check the licence before you place the order.
How many factories are on the panel?: The table above states, per API specification, how many signed panel factories hold that licence in force. Every factory on the panel has signed an agreement with us that includes no-bypass terms. The counts are published; the factory list is not.

Standards cited

API Spec 6D: Pipeline and piping valves: design, manufacture, testing and documentation of ball, gate, plug and check valves.
API Std 609: Butterfly valves: Category A (concentric) and Category B (double and triple offset) for ASME Class 150 to 600.
API Std 608: Metal ball valves with flanged, threaded and welding ends.