PostgreSQL function for automatic Object IDs. Inspired by Stripe: https://dev.to/stripe/designing-apis-for-humans-object-ids-3o5a

prefixed_random_id.sql

CREATE OR REPLACE FUNCTION random_string(length INTEGER) RETURNS TEXT AS $$
DECLARE
  chars TEXT[] := ARRAY['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
  result TEXT := '';
  i INTEGER;
BEGIN
  FOR i IN 1..length LOOP
    result := result || chars[1 + RANDOM() * (array_length(chars, 1) - 1)];
  END LOOP;
  RETURN result;
END;
$$ LANGUAGE plpgsql VOLATILE;

CREATE OR REPLACE FUNCTION prefixed_random_id(prefix TEXT)
RETURNS TEXT AS $$
BEGIN
    RETURN prefix || '_' || random_string(24);
END;
$$ LANGUAGE plpgsql;

usage.sql

CREATE TABLE "user" (
    "id" TEXT NOT NULL DEFAULT prefixed_random_id('u'::text),
);
-- example of `id` value: u_k81fapyf1l7b8wc2kd94fc05