Xindi technology
At the time of the Xindi crisis, Xindi technology was advanced compared with that of Starfleet. It could also be very different from any technology Humans had experience with. ()

Each of the five remaining species had their own distinct technologies, as well as their own ship designs. Some of their technologies had been developed with the help of the highly advanced Sphere-Builders. Partly as a result of this alliance, many of their technologies were unique to the Xindi, including their subspace portals, and their fearsome planet-destroying capabilities.

Starships
Also see: Xindi starship classes

By the mid-22nd century, all five remaining Xindi species were warp-capable. In addition, Xindi-ships had the unique ability to be able to travel through a subspace portal system, resulting in travel times considerably faster than standard warp. 

Standard Xindi weaponry appeared to be on par with the phase cannons on a Starfleet  ship. Xindi ships had different design lineages based upon the race who built them.

 Xindi-Insectoid ships typically consisted of multiple prongs (presumably part of the propulsion system). They had no centralized control system, and ships were equipped with a shielded hatchery where Insectoid eggs were kept. The larger Insectoid ships were equipped with relatively powerful weapons, but were apparently inferior to Reptilian warships.

 Xindi-Reptilian ships were combat-oriented. They had multiple weapons mounted on an irregular-shaped hull consisting of a broad bow with deflector dish that tapered into three long aft prongs, likely a part of the propulsion mechanism. Reptilian quarters had large sunlamps that kept the crew active and warm. Degra contributed to the design of their power systems.

 Little is known of Xindi-Aquatic ships. They had large, open tanks in which the Aquatics attended to their duties and managed all shipboard functions. The largest of their ships resembled huge Terran manta rays, and were large enough to comfortably accommodate an NX-class vessel in its aft cargo hold. There were six such ships at the battle to destroy the Xindi weapon, during its arming sequence. They were extremely powerful, destroying several Reptilian and Insectoid ships with ease, and an immense anomaly field was required to disable three of them. However, compared to Primate and Insectoid ships, the Aquatic ships were slow and not as maneuverable.

 Xindi-Primate ships tended to have elongated hulls. Degra's ship had multiple spiked prongs protruding forward from a streamlined, tapered hull. Another ship, presumably of Primate design (as it was commanded by the other Primate Council member), also featured forward, aggressive spikes, indicating a Primate design lineage. This ship was significantly larger than Degra's.

 Several Xindi-Arboreal ships were built and deployed. One was a two-man shuttle found on the surface of the Loque'eque homeworld. There were also several Arboreal ships that escorted Enterprise to the Xindi Council chamber. The ships had a long oval-shaped hull with four vertical engine nozzles in the dorsal-aft area. As with Primate ships, they had few weapons and were considered no match for the Reptilians and Insectoids.

Planet-destroying technology

Without a doubt the most dramatic and unique Xindi technology lied in their planet-destroying capabilities.

During the 2030s, a century-long war between the six Xindi species ended dramatically when the insectoids and reptilians managed to detonate massive explosions beneath the eight largest seismic fissures of Xindus. This grim feat was helped by the fact that the homeworld was geologically unstable.

More than a century later, upon learning of the so-called "Human threat," a Xindi engineer by the name of Degra designed a large probe capable of destroying an entire planet. It may have incorporated technology from all five existing species. The final weapon was capable of generating the power necessary to obliterate an entire planet, though it required command codes from at least three of the five Xindi Council members to activate the firing sequence. The Reptilians and Insectoids planned to overcome this by brainwashing Hoshi Sato into decoding the third code, to bring the weapon online.

Time travel 
With the help of the Guardians, a Xindi-Reptilian team on at least one occasion managed to travel back in time, to 2004. ()

Species-specific technologies

Xindi-Aquatics

As was to be expected for an aquatic species, Xindi-Aquatics were capable of building large structures underwater. ()

Their innate distrust of the written word lead the Xindi-Aquatics to develop biometric holograms: hard to fake visual representations of biometric info. By the mid-22nd century, biometric holograms were used in the training of doctors of all Xindi species. ()

Xindi-Insectoids
Xindi-Insectoids were known to maintain hatcheries on their ships. ()

Xindi-Reptilians

The most aggressive of the Xindi species, Xindi-Reptilians were well-armed when it came to personal combat. Seemingly uniquely amongst the Xindi species, many of their weapons incorporated biotechnology.

Their deadly biorifles possessed an organism known as a techno-larva. Its neural pathways modulated the rifle's power output; Doctor Phlox considered it the most sophisticated example of bio-mechanical engineering he had ever seen. The organism could be killed with a sustained burst of delta radiation. Omicron radiation, however, caused the organism to thrive. ()

Another hand-held weapon was the Xindi-Reptilian ray gun. ()

The Reptilians also possessed grenade launchers that fired organic grenades. () For reconnaissance, Reptilians used a type of flying drone called a seeker. It too had biological components, and could in fact be mistaken by a scanner for an actual Xindi biosign. ()

Another example of Xindi bioengineering was their formidable neural parasites, which were used for interrogations. ()

Perhaps unsurprisingly, Xindi-Reptilians lobbied the Xindi bio-weapon as an alternative means of destroying Humanity. Their weapon was variously described as a viral agent and a toxin. A key tool for bio-weapon research was the bio-reactor. ()

Some Xindi-Reptilians were also surgically enhanced; their suicide glands were a result of this. ()

Reptilian body armor was very resilient, able to withstand several shots from Terran phase-pistols, and even the more advanced MACO weaponry. () The standard military Reptilian blade had a polymer-based hilt.

Typically, a Xindi-Reptilian ship also contained an area called a thermal chamber, an excessively heated chamber. ()

Other technology
A Xindi database was recovered by  in 2153, and proved to be a key intelligence find. ()

The Xindi had the ability to refine Kemocite up to less than six parts per million of impurities. ()

Background information 
Several prop pieces of Xindi technology were sold off on the It's A Wrap! sale and auction on eBay, including two console buttons. 
Technology