Certer is a random event. Certers Miles, Niles, or Giles teleport a player to their office and present them with a rotating image of an item, and three possible choices of what it is. If a player correctly identifies the item, they will receive a Random event gift and are free to use the exit portal. An incorrect choice will result in the player's equipment and inventory being noted and the player being teleported to a random location.
Their new office includes a working Deposit box. You cannot access all your controls whilst in this office. For instance, you cannot use Prayer, but if you had prayers active before you were teleported here, you would be teleported back with the prayer still active but not having been drained.
In RuneScape Classic, the Certers ran exchange stalls around RuneScape converting various items into certificates (certs for short) for large quantity trading. Five of the items traded for one certificate, which were stackable. The tedious process involved making many trips from the bank to the certers.
- Niles: raw/cooked lobster and swordfish (there was also a member certer called seth for this fish he is located in brimhaven)
- Tom and Sam: raw/cooked bass and shark
- Giles: iron ore, coal, mithril ore, gold ore, and silver ore
- Miles: iron, steel, mithril, gold, and silver bars
- Chuck: willow, maple, and yew logs
- Sidney Smith: super attack potions, super defence potions, super strength potion, prayer potions, dragon bones, limpwurt roots
When RuneScape 2 was released, the certers were removed from the game because the bank note system rendered them obsolete. Existing certificates were all converted into bank notes. Niles, Giles and Miles were soon re-released as this random event in reference to their old trade but the other certers were not.
|“||We are most hopeful that this little piece of bureaucracy will soon be a thing of the past, and we can all go on a well-deserved holiday, or possibly even retire.||”|
— Giles 
Although this suggests that this random event would have been removed, it was only modified in the Random Event Update and More update.
Before the Random event rework, one of the Certers appeared next to the player. The question window opened when talking to the certer. If ignored, he gave the player four warnings. If the player yet ignored him, he teleported the player to a random, relatively safe place and turned his inventory and equipment into bank notes. Some players considered this very annoying during combat.
- When a player encounters a certer underwater, the certer will be wearing the same diving apparatus as the player.
- Many have pointed out that these certers ask you a question, appearing that they genuinely need the answer, but they know which answer is right or wrong when you answer the question.
- The certers used to only note items; however, players took advantage of this by dropping any items they wished to remain un-noted and then answering incorrectly, resulting in the certers noting their raw materials and allowing the player to carry more. The only certer who still does this is Stiles located on Musa Point.
- The office resembles the office of Death when a player first dies.