What is the length and type of PayPal's transaction ID (txn_id)?

Question

I want to store PayPal transaction IDs. What is the length and type I need to set on that field in the database? Currently, I set varchar(128). Is that sufficient?

Answer 1

In the transaction search API it suggests the maximum length of a transaction ID is 19 single bytes. The transaction id is alphanumeric so a varchar(19) would be fine.

Personally I'd go for varchar(20) just in case they max out on transaction ids and need to add an extra digit :)