Supabase API errorSupabase: “Could not find the function in the schema cache” (PGRST202)

Why the function is not found, and the fix

1. 01

   The argument names do not match

   “The function parameter names match the JSON object keys in the POST case” GitHub, PostgREST docs: Functions as RPC

   Arguments are matched by name, not position. rpc('add_item', { item_id: 1 }) only finds a function whose parameter is called item_id. A parameter named p_item_id, a missing argument without a default, or extra keys all give PGRST202. The error’s hint may name the closest match.

   -- SQL
   create function add_item(p_item_id bigint) returns void ...
   
   // JS: use the SQL parameter names
   await supabase.rpc('add_item', { p_item_id: 1 });

2. 02

   The name has capital letters

   Postgres lowercases unquoted names, so create function addItem(...) makes a function called additem, and rpc('addItem') does not find it. Use snake_case names for functions you call from the API.

3. 03

   The schema cache is stale

   “Caused by a stale function signature, otherwise the function may not exist in the database.” Supabase, PostgREST error codes (PGRST202)

   After you create or change a function, the API may still use the old list. Reload it from the SQL editor.

   NOTIFY pgrst, 'reload schema';

4. 04

   The function is in another schema

   “When multiple schemas are exposed, the first entry in the list is treated as the default, so PostgREST resolves unqualified object names only against that schema.” Supabase, PostgREST not recognizing objects in schema

   A function in a schema other than public needs that schema exposed in the API settings, and the call has to name it with .schema('name').rpc(...).

5. 05

   The function exists only in another project

   A migration that ran on your local or staging database but not on production leaves the function missing where the app points. Check in the SQL editor of the project the app uses.

   select proname, pg_get_function_arguments(oid)
   from pg_proc where proname = 'add_item';

6. 06

   Calling it from the client

   “If the function is defined to have default values for the parameters then arguments for these parameters can be omitted in the request.” GitHub, PostgREST docs: Functions as RPC

   The second argument to rpc() is the object of named arguments. You can leave out only the arguments whose parameters have defaults in SQL.

Checked against the vendor’s docs on November 8, 2026: Supabase docs: PostgREST error codes; Supabase troubleshooting: Reload the PostgREST schema; Supabase troubleshooting: Objects in an exposed schema; Supabase reference: JavaScript rpc; PostgREST docs: Functions as RPC.

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