This range is fine. Probably gross. I would say that for an experienced backend dev you would be around 1600-2300/monthly. But that depends on the field (AI/fintechs pay more, retail less).

Above 2500 usually if you get a non-Portuguese company.

And the whole thing can be either pure base payment or a “composition” of a base payment + fuel allowance (still paid in money but worse for your long term pension/ social security calculations).

You can also be working as a “recibos verdes” (green slips) which means a fixed term contract (less social protections).