Building on openFDA yourself

openFDA, DailyMed, RxNorm and the Orange Book are free. Connecting them is the work.

Job	From the free sources	From EntropyAPI
Read any NDC	NDCs come in three 10-digit layouts, and billing uses 11 digits. 12345-0678-09 could be 12345-678-09 or 12345-0678-9.	Send any layout. An ambiguous code returns every candidate, never a guess.
Find the label	180,277 of 262,902 openFDA label records carry no product NDC.	Each NDC links to its DailyMed label through the label’s own package NDCs.
Check a lot against recalls	Recall lots arrive as free text, such as “Lot #: 072915, Exp 10/29/2015”. 15,015 of 18,048 recall records carry no product NDC.	Recall text is read for NDCs and whole lot codes. Check up to 100 items in one request.
Get the equivalence rating	Orange Book files are keyed on application and product number. None of the three files lists an NDC.	The rating comes back with the product, matched by its own application.
Connect RxNorm	RxNorm returns NDCs as 11 digits without hyphens. openFDA and labels use hyphenated 10-digit forms.	An NDC, an RxCUI or a UNII goes to the same lookup.
Keep it current	Each source keeps its own schedule: openFDA labels weekly, NDCs daily, RxNorm monthly. Dates arrive in different formats.	Sources are checked daily or more often. Every data response lists each source with its date.

Read any NDCNDCs come in three 10-digit layouts, and billing uses 11 digits. 12345-0678-09 could be 12345-678-09 or 12345-0678-9.Send any layout. An ambiguous code returns every candidate, never a guess.
Find the label180,277 of 262,902 openFDA label records carry no product NDC.Each NDC links to its DailyMed label through the label’s own package NDCs.
Check a lot against recallsRecall lots arrive as free text, such as “Lot #: 072915, Exp 10/29/2015”. 15,015 of 18,048 recall records carry no product NDC.Recall text is read for NDCs and whole lot codes. Check up to 100 items in one request.
Get the equivalence ratingOrange Book files are keyed on application and product number. None of the three files lists an NDC.The rating comes back with the product, matched by its own application.
Connect RxNormRxNorm returns NDCs as 11 digits without hyphens. openFDA and labels use hyphenated 10-digit forms.An NDC, an RxCUI or a UNII goes to the same lookup.
Keep it currentEach source keeps its own schedule: openFDA labels weekly, NDCs daily, RxNorm monthly. Dates arrive in different formats.Sources are checked daily or more often. Every data response lists each source with its date.

Counts read from api.fda.gov on 2026-10-26.

Where these facts come from