While these two types may seem very different, they do share quite a few similarities which can make them difficult to tell apart.
INTP vs INFJ
The INTP and INFJ both are intuitive introverts. The INTP is analytical but the INFJ is surprisingly analytical in a similar way as well. The INFJ is very good at reading others emotions, but the INTP is also good at doing this with people they are close to.
The INTP is good at seeing multiple possibilities and analyzing them to get a better understanding of how things work. They are also typically a bit more traditional in nature.
The INFJ has a distinct inner world in that they take in sensory information that gives them some insight into the future. They are good at understanding how to navigate the world to get to where they want.
In order to have a deeper understanding of the differences of each type, it is best to look at their function stacks.
INTP Function Stack:
Introverted Thinking
Extraverted Intuition
Introverted Sensing
Extraverted Feeling
INFJ Function Stack:
Introverted Intuition
Extraverted Feeling
Introverted Thinking
Extraverted Sensing
A way to identify each type is to understand how each type reacts under stress.
The INTP and INFJ Under Stress
The INTP under stress will use their weak Extraverted Feeling function a bit more. The normally reserved INTP may become a bit more agitated and “snappy” toward people and problems they can’t solve easily. Frustrated by their lack of ability to sort things out, they may become uncharacteristically emotional and moody.
The INFJ a under stress will use their weak Extraverted Sensing function a bit more. The INFJ, typically a person with a lot of planning and foresight, will engage in a lot more impulsive behaviors. The INFJ may become stressed and can engage in risky activities like promiscuity, drugs and alcohol, or spending their money foolishly.